Update GDB to newest version #2

janmaartenbuis · 2022-06-20T15:31:58Z

From what I know, the reason an older version of GDB is included in this repo is because of the connection error that appears in later GDB versions. I've traced the assert error in the GDB source code and I think I've fixed it. I've been using GDB 12.1 (build for ppc) on Linux in combination with the gdbstub for debugging GameCube homebrew over the BBA and it works fine.
I don't have permission to push to this repo, but I'd be happy to share my fix if you're interested.

In the case where a Fortran program has a program name of "main" and there is also a minimal symbol called main, such as with programs built with GCC version 4.4.7 or below, the backtrace will erroneously stop at the minimal symbol rather than the user specified main, e.g.: (gdb) bt #0 bar () at .../gdb/testsuite/gdb.fortran/backtrace.f90:17 #1 0x0000000000402556 in foo () at .../gdb/testsuite/gdb.fortran/backtrace.f90:21 #2 0x0000000000402575 in main () at .../gdb/testsuite/gdb.fortran/backtrace.f90:31 bminor#3 0x00000000004025aa in main () (gdb) This patch fixes this issue by increasing the precedence of the full symbol when the language of the current frame is Fortran. Newer versions of GCC transform the program name to "MAIN__" in this case, avoiding the problem. Co-Authored-By: Maciej W. Rozycki <macro@embecosm.com>

digitall · 2023-05-17T12:27:13Z

@janmaartenbuis : If you still have this patch, could you share it as a github gist or similar as trying to sort out GDB for the Wii when using newer GDB than 7.7.1 ...

WinterMute · 2023-05-18T16:01:10Z

This repo contains only upstream gdb & patches for devkitARM-gdb. This is not the appropriate place for this issue nor is the issue with gdb.

janmaartenbuis · 2023-05-18T16:44:27Z

@WinterMute sorry, my bad. For me the issue was very much GDB. Any suggestion where I could share this then?

digitall · 2023-05-18T18:45:31Z

@WinterMute : Can you please indicate where in the devkitPro org, the repository for gdb for Wii / Gamecube is generated / built from then? I haven't been able to locate this and thought that this was the source repo...

digitall · 2023-05-18T18:47:12Z

@janmaartenbuis : You can create a public gist as per https://docs.github.com/en/get-started/writing-on-github/editing-and-sharing-content-with-gists/creating-gists ... Once done, drop me a message at @scummvm.org. Thanks.

@WinterMute, @devkitPro: Sorry for the noise. Will not bother you further.

WinterMute · 2023-05-19T10:05:59Z

@WinterMute sorry, my bad. For me the issue was very much GDB. Any suggestion where I could share this then?

Would very much prefer if you kept it to yourself. The issue lies primarily with libogc's debug stub which requires updating for latest gdb.

WinterMute · 2023-05-19T10:09:48Z

@WinterMute : Can you please indicate where in the devkitPro org, the repository for gdb for Wii / Gamecube is generated / built from then? I haven't been able to locate this and thought that this was the source repo...

The gdb we supply for devkitPPC is built from vanilla sources. If we ever patch gdb then there will be a branch in this repository.

We would also very much appreciate it if people weren't encouraged to share and use inappropriate patches.

janmaartenbuis · 2023-05-19T15:40:43Z

@WinterMute As you wish. Just trying to be helpful.

digitall · 2023-05-21T17:34:51Z

@WinterMute : I understand that, but I think you have an issue with the powerpc-eabi-gdb shipped with r43 i.e. 20230501 release hence why I am doing this. That is v7.6.2 which I assume is to allow it to work correctly with the debugging stub for the Wii since that breaks for remote debugging after v7.7.1.

However, that version of GDB only understands DWARF v4 and lower. However, your updates to the GCC toolchain now mean that -g builds the library code with DWARF v5 by default, hence the gdb shipped can't load the debug symbols of any executable which has been linked against libogc etc. :|

The solution is for you to fix the library build scripts to pass "-gdwarf-4" and I will need to add the same to my application build scripts to work with GDB v7.6.2 ...

digitall · 2023-05-21T17:37:34Z

The other solution would be to update the toolchain to a newer GDB version... but as you have indicated that would need updates / changes to the Wii debugging stub code. I didn't spot this previously, but that is https://github.com/devkitPro/libogc/tree/master/libdb if I am correct?

WinterMute · 2023-05-29T18:02:05Z

The other solution would be to update the toolchain to a newer GDB version... but as you have indicated that would need updates / changes to the Wii debugging stub code. I didn't spot this previously, but that is https://github.com/devkitPro/libogc/tree/master/libdb if I am correct?

It is, yes. I found some time to look at it sorted the problem & updated gdb to 13.2 so it's all good now.

digitall · 2023-05-29T19:57:35Z

@WinterMute : Thank you very much for doing that.
I can shelve the pending PRs I was making to add -gdwarf-4 in far too many places :)
Can I check a couple of points:

Did you test this with a real USB Gecko in a Wii to see if it connects to the target correctly?
I looked at the GDB remote protocol implementation in https://github.com/devkitPro/libogc/blob/master/libdb/debug.c#L300. This is a bit sparse currently compared to https://sourceware.org/gdb/onlinedocs/gdb/General-Query-Packets.html.
I did some testing myself with Dolphin's virtual USB Gecko and the older gdb-3.6.2 and this worked, but from the warning / errors emitted, I think that qSupported should be implemented as a minimum to avoid issues in future: https://sourceware.org/gdb/onlinedocs/gdb/General-Query-Packets.html#qSupported.
If you are busy or I am adding a task, I can look at sending a PR for this myself if you are open to that?

WinterMute · 2023-05-29T21:40:51Z

@digitall Tested with real usb gecko on Wii & tcp/ip on cube. Logs attached on devkitPro/libogc#154

Do feel free to PR qSupported packet support, would be much appreciated.

digitall · 2023-05-29T21:56:06Z

@WinterMute: Thanks. Will look at adding in qSupported if I can and any other packets.
One further point, it isn't well documented that the GDB_NETWORK_TCP only works on the Gamecube with the Broad Band Adapter, though I suppose you could connect a BBA to the EXI ports on a Wii, but I haven't seen a cable / adaptor to do that.

Since the USB Gecko is practically impossible to get now (and I don't have one) and building a Shuriken is a problem since the XC9500 CPLD is also unobtainium, I was aiming to look at using GDB_NETWORK_TCP on the Wii. This was done once previously, but the code was not upstreamed to libogc and the links for the code patches are now all dead: https://wiibrew.org/wiki/User:Qiang0/Debugging#Debugging_Homebrew_apps_without_Gecko_USB

However, I assume this would entail using the IOS network API calls instead of the bba.h API.
Any views on whether this would work and do you have a copy of that RAR file?

Expect a `.MIPS.options' section alternatively to `.reginfo' and ignore contents of either as irrelevant for all the affected compact EH tests, removing these regressions: mips64-openbsd -FAIL: Compact EH EB #1 with personality ID and FDE data mips64-openbsd -FAIL: Compact EH EB #2 with personality routine and FDE data mips64-openbsd -FAIL: Compact EH EB bminor#3 with personality id and large FDE data mips64-openbsd -FAIL: Compact EH EB bminor#4 with personality id, FDE data and LSDA mips64-openbsd -FAIL: Compact EH EB bminor#5 with personality routine, FDE data and LSDA mips64-openbsd -FAIL: Compact EH EB bminor#6 with personality id, LSDA and large FDE data mips64-openbsd -FAIL: Compact EH EL #1 with personality ID and FDE data mips64-openbsd -FAIL: Compact EH EL #2 with personality routine and FDE data mips64-openbsd -FAIL: Compact EH EL bminor#3 with personality id and large FDE data mips64-openbsd -FAIL: Compact EH EL bminor#4 with personality id, FDE data and LSDA mips64-openbsd -FAIL: Compact EH EL bminor#5 with personality routine, FDE data and LSDA mips64-openbsd -FAIL: Compact EH EL bminor#6 with personality id, LSDA and large FDE data mips64el-openbsd -FAIL: Compact EH EB #1 with personality ID and FDE data mips64el-openbsd -FAIL: Compact EH EB #2 with personality routine and FDE data mips64el-openbsd -FAIL: Compact EH EB bminor#3 with personality id and large FDE data mips64el-openbsd -FAIL: Compact EH EB bminor#4 with personality id, FDE data and LSDA mips64el-openbsd -FAIL: Compact EH EB bminor#5 with personality routine, FDE data and LSDA mips64el-openbsd -FAIL: Compact EH EB bminor#6 with personality id, LSDA and large FDE data mips64el-openbsd -FAIL: Compact EH EL #1 with personality ID and FDE data mips64el-openbsd -FAIL: Compact EH EL #2 with personality routine and FDE data mips64el-openbsd -FAIL: Compact EH EL bminor#3 with personality id and large FDE data mips64el-openbsd -FAIL: Compact EH EL bminor#4 with personality id, FDE data and LSDA mips64el-openbsd -FAIL: Compact EH EL bminor#5 with personality routine, FDE data and LSDA mips64el-openbsd -FAIL: Compact EH EL bminor#6 with personality id, LSDA and large FDE data Co-Authored-By: Maciej W. Rozycki <macro@orcam.me.uk> gas/ * testsuite/gas/mips/compact-eh-eb-1.d: Accept `.MIPS.options' section as an alternative to `.reginfo' and ignore contents of either. * testsuite/gas/mips/compact-eh-eb-2.d: Likewise. * testsuite/gas/mips/compact-eh-eb-3.d: Likewise. * testsuite/gas/mips/compact-eh-eb-4.d: Likewise. * testsuite/gas/mips/compact-eh-eb-5.d: Likewise. * testsuite/gas/mips/compact-eh-eb-6.d: Likewise. * testsuite/gas/mips/compact-eh-el-1.d: Likewise. * testsuite/gas/mips/compact-eh-el-2.d: Likewise. * testsuite/gas/mips/compact-eh-el-3.d: Likewise. * testsuite/gas/mips/compact-eh-el-4.d: Likewise. * testsuite/gas/mips/compact-eh-el-5.d: Likewise. * testsuite/gas/mips/compact-eh-el-6.d: Likewise.

With gdb build with -fsanitize=thread and test-case gdb.base/index-cache.exp I run into: ... (gdb) file build/gdb/testsuite/outputs/gdb.base/index-cache/index-cache Reading symbols from build/gdb/testsuite/outputs/gdb.base/index-cache/index-cache... (gdb) show index-cache enabled The index cache is off. (gdb) PASS: gdb.base/index-cache.exp: test_basic_stuff: index-cache is disabled by default set index-cache enabled on ================== WARNING: ThreadSanitizer: data race (pid=32248) Write of size 1 at 0x00000321f540 by main thread: #0 index_cache::enable() gdb/dwarf2/index-cache.c:76 (gdb+0x82cfdd) #1 set_index_cache_enabled_command gdb/dwarf2/index-cache.c:270 (gdb+0x82d9af) #2 bool setting::set<bool>(bool const&) gdb/command.h:353 (gdb+0x6fe5f2) bminor#3 do_set_command(char const*, int, cmd_list_element*) gdb/cli/cli-setshow.c:414 (gdb+0x6fcd21) bminor#4 execute_command(char const*, int) gdb/top.c:567 (gdb+0xff2e64) bminor#5 command_handler(char const*) gdb/event-top.c:552 (gdb+0x94acc0) bminor#6 command_line_handler(std::unique_ptr<char, gdb::xfree_deleter<char> >&&) gdb/event-top.c:788 (gdb+0x94b37d) bminor#7 tui_command_line_handler gdb/tui/tui-interp.c:104 (gdb+0x103467e) bminor#8 gdb_rl_callback_handler gdb/event-top.c:259 (gdb+0x94a265) bminor#9 rl_callback_read_char readline/readline/callback.c:290 (gdb+0x11bdd3f) bminor#10 gdb_rl_callback_read_char_wrapper_noexcept gdb/event-top.c:195 (gdb+0x94a064) bminor#11 gdb_rl_callback_read_char_wrapper gdb/event-top.c:234 (gdb+0x94a125) bminor#12 stdin_event_handler gdb/ui.c:155 (gdb+0x1074922) #13 handle_file_event gdbsupport/event-loop.cc:573 (gdb+0x1d94de4) #14 gdb_wait_for_event gdbsupport/event-loop.cc:694 (gdb+0x1d9551c) #15 gdb_do_one_event(int) gdbsupport/event-loop.cc:264 (gdb+0x1d93908) #16 start_event_loop gdb/main.c:412 (gdb+0xb5a256) #17 captured_command_loop gdb/main.c:476 (gdb+0xb5a445) #18 captured_main gdb/main.c:1320 (gdb+0xb5c5c5) #19 gdb_main(captured_main_args*) gdb/main.c:1339 (gdb+0xb5c674) #20 main gdb/gdb.c:32 (gdb+0x416776) Previous read of size 1 at 0x00000321f540 by thread T12: #0 index_cache::enabled() const gdb/dwarf2/index-cache.h:48 (gdb+0x82e1a6) #1 index_cache::store(dwarf2_per_bfd*) gdb/dwarf2/index-cache.c:94 (gdb+0x82d0bc) #2 cooked_index::maybe_write_index(dwarf2_per_bfd*) gdb/dwarf2/cooked-index.c:638 (gdb+0x7f1b97) bminor#3 operator() gdb/dwarf2/cooked-index.c:468 (gdb+0x7f0f24) bminor#4 _M_invoke /usr/include/c++/7/bits/std_function.h:316 (gdb+0x7f285b) bminor#5 std::function<void ()>::operator()() const /usr/include/c++/7/bits/std_function.h:706 (gdb+0x700952) bminor#6 void std::__invoke_impl<void, std::function<void ()>&>(std::__invoke_other, std::function<void ()>&) /usr/include/c++/7/bits/invoke.h:60 (gdb+0x7381a0) bminor#7 std::__invoke_result<std::function<void ()>&>::type std::__invoke<std::function<void ()>&>(std::function<void ()>&) /usr/include/c++/7/bits/invoke.h:95 (gdb+0x737e91) bminor#8 std::__future_base::_Task_state<std::function<void ()>, std::allocator<int>, void ()>::_M_run()::{lambda()#1}::operator()() const /usr/include/c++/7/future:1421 (gdb+0x737b59) bminor#9 std::__future_base::_Task_setter<std::unique_ptr<std::__future_base::_Result<void>, std::__future_base::_Result_base::_Deleter>, std::__future_base::_Task_state<std::function<void ()>, std::allocator<int>, void ()>::_M_run()::{lambda()#1}, void>::operator()() const /usr/include/c++/7/future:1362 (gdb+0x738660) bminor#10 std::_Function_handler<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> (), std::__future_base::_Task_setter<std::unique_ptr<std::__future_base::_Result<void>, std::__future_base::_Result_base::_Deleter>, std::__future_base::_Task_state<std::function<void ()>, std::allocator<int>, void ()>::_M_run()::{lambda()#1}, void> >::_M_invoke(std::_Any_data const&) /usr/include/c++/7/bits/std_function.h:302 (gdb+0x73825c) bminor#11 std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>::operator()() const /usr/include/c++/7/bits/std_function.h:706 (gdb+0x733623) bminor#12 std::__future_base::_State_baseV2::_M_do_set(std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*) /usr/include/c++/7/future:561 (gdb+0x732bdf) #13 void std::__invoke_impl<void, void (std::__future_base::_State_baseV2::*)(std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*), std::__future_base::_State_baseV2*, std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*>(std::__invoke_memfun_deref, void (std::__future_base::_State_baseV2::*&&)(std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*), std::__future_base::_State_baseV2*&&, std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*&&, bool*&&) /usr/include/c++/7/bits/invoke.h:73 (gdb+0x734c4f) #14 std::__invoke_result<void (std::__future_base::_State_baseV2::*)(std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*), std::__future_base::_State_baseV2*, std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*>::type std::__invoke<void (std::__future_base::_State_baseV2::*)(std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*), std::__future_base::_State_baseV2*, std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*>(void (std::__future_base::_State_baseV2::*&&)(std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*), std::__future_base::_State_baseV2*&&, std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*&&, bool*&&) /usr/include/c++/7/bits/invoke.h:95 (gdb+0x733bc5) #15 std::call_once<void (std::__future_base::_State_baseV2::*)(std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*), std::__future_base::_State_baseV2*, std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*>(std::once_flag&, void (std::__future_base::_State_baseV2::*&&)(std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*), std::__future_base::_State_baseV2*&&, std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*&&, bool*&&)::{lambda()#1}::operator()() const /usr/include/c++/7/mutex:672 (gdb+0x73300d) #16 std::call_once<void (std::__future_base::_State_baseV2::*)(std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*), std::__future_base::_State_baseV2*, std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*>(std::once_flag&, void (std::__future_base::_State_baseV2::*&&)(std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*), std::__future_base::_State_baseV2*&&, std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*&&, bool*&&)::{lambda()#2}::operator()() const /usr/include/c++/7/mutex:677 (gdb+0x7330b2) #17 std::call_once<void (std::__future_base::_State_baseV2::*)(std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*), std::__future_base::_State_baseV2*, std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*>(std::once_flag&, void (std::__future_base::_State_baseV2::*&&)(std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*), std::__future_base::_State_baseV2*&&, std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*&&, bool*&&)::{lambda()#2}::_FUN() /usr/include/c++/7/mutex:677 (gdb+0x7330f2) #18 pthread_once <null> (libtsan.so.0+0x4457c) #19 __gthread_once /usr/include/c++/7/x86_64-suse-linux/bits/gthr-default.h:699 (gdb+0x72f5dd) #20 void std::call_once<void (std::__future_base::_State_baseV2::*)(std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*), std::__future_base::_State_baseV2*, std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*>(std::once_flag&, void (std::__future_base::_State_baseV2::*&&)(std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*), std::__future_base::_State_baseV2*&&, std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*&&, bool*&&) /usr/include/c++/7/mutex:684 (gdb+0x733224) #21 std::__future_base::_State_baseV2::_M_set_result(std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>, bool) /usr/include/c++/7/future:401 (gdb+0x732852) #22 std::__future_base::_Task_state<std::function<void ()>, std::allocator<int>, void ()>::_M_run() /usr/include/c++/7/future:1423 (gdb+0x737bef) #23 std::packaged_task<void ()>::operator()() /usr/include/c++/7/future:1556 (gdb+0x1dac492) #24 gdb::thread_pool::thread_function() gdbsupport/thread-pool.cc:242 (gdb+0x1dabdb4) #25 void std::__invoke_impl<void, void (gdb::thread_pool::*)(), gdb::thread_pool*>(std::__invoke_memfun_deref, void (gdb::thread_pool::*&&)(), gdb::thread_pool*&&) /usr/include/c++/7/bits/invoke.h:73 (gdb+0x1dace63) #26 std::__invoke_result<void (gdb::thread_pool::*)(), gdb::thread_pool*>::type std::__invoke<void (gdb::thread_pool::*)(), gdb::thread_pool*>(void (gdb::thread_pool::*&&)(), gdb::thread_pool*&&) /usr/include/c++/7/bits/invoke.h:95 (gdb+0x1dac294) #27 decltype (__invoke((_S_declval<0ul>)(), (_S_declval<1ul>)())) std::thread::_Invoker<std::tuple<void (gdb::thread_pool::*)(), gdb::thread_pool*> >::_M_invoke<0ul, 1ul>(std::_Index_tuple<0ul, 1ul>) /usr/include/c++/7/thread:234 (gdb+0x1daf5c6) #28 std::thread::_Invoker<std::tuple<void (gdb::thread_pool::*)(), gdb::thread_pool*> >::operator()() /usr/include/c++/7/thread:243 (gdb+0x1daf551) #29 std::thread::_State_impl<std::thread::_Invoker<std::tuple<void (gdb::thread_pool::*)(), gdb::thread_pool*> > >::_M_run() /usr/include/c++/7/thread:186 (gdb+0x1daf506) #30 <null> <null> (libstdc++.so.6+0xdcac2) Location is global 'global_index_cache' of size 48 at 0x00000321f520 (gdb+0x00000321f540) ... SUMMARY: ThreadSanitizer: data race gdb/dwarf2/index-cache.c:76 in index_cache::enable() ... The race happens when issuing a "file $exec" command followed by a "set index-cache enabled on" command. The race is between: - a worker thread reading index_cache::m_enabled to determine whether an index-cache entry for $exec needs to be written (due to command "file $exec"), and - the main thread setting index_cache::m_enabled (due to command "set index-cache enabled on"). Fix this by capturing the value of index_cache::m_enabled in the main thread, and using the captured value in the worker thread. Tested on x86_64-linux. PR symtab/30392 Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=30392

With gdb build with -fsanitize=thread and test-case gdb.base/index-cache.exp I run into: ... (gdb) file build/gdb/testsuite/outputs/gdb.base/index-cache/index-cache Reading symbols from build/gdb/testsuite/outputs/gdb.base/index-cache/index-cache... ================== WARNING: ThreadSanitizer: data race (pid=12261) Write of size 4 at 0x7b4400097d08 by main thread: #0 bfd_open_file bfd/cache.c:584 (gdb+0x148bb92) #1 bfd_cache_lookup_worker bfd/cache.c:261 (gdb+0x148b12a) #2 cache_bseek bfd/cache.c:289 (gdb+0x148b324) bminor#3 bfd_seek bfd/bfdio.c:459 (gdb+0x1489c31) bminor#4 _bfd_generic_get_section_contents bfd/libbfd.c:1069 (gdb+0x14977a4) bminor#5 bfd_get_section_contents bfd/section.c:1606 (gdb+0x149cc7c) bminor#6 gdb_bfd_scan_elf_dyntag(int, bfd*, unsigned long*, unsigned long*) gdb/solib.c:1601 (gdb+0xed8eca) bminor#7 elf_locate_base gdb/solib-svr4.c:705 (gdb+0xec28ac) bminor#8 svr4_iterate_over_objfiles_in_search_order gdb/solib-svr4.c:3430 (gdb+0xeca55d) bminor#9 gdbarch_iterate_over_objfiles_in_search_order(gdbarch*, gdb::function_view<bool (objfile*)>, objfile*) gdb/gdbarch.c:5041 (gdb+0x537cad) bminor#10 find_main_name gdb/symtab.c:6270 (gdb+0xf743a5) bminor#11 main_language() gdb/symtab.c:6313 (gdb+0xf74499) bminor#12 set_initial_language() gdb/symfile.c:1700 (gdb+0xf4285c) #13 symbol_file_add_main_1 gdb/symfile.c:1212 (gdb+0xf40e2a) #14 symbol_file_command(char const*, int) gdb/symfile.c:1681 (gdb+0xf427d1) #15 file_command gdb/exec.c:554 (gdb+0x94f74b) #16 do_simple_func gdb/cli/cli-decode.c:95 (gdb+0x6d9528) #17 cmd_func(cmd_list_element*, char const*, int) gdb/cli/cli-decode.c:2735 (gdb+0x6e0f69) #18 execute_command(char const*, int) gdb/top.c:575 (gdb+0xff303c) #19 command_handler(char const*) gdb/event-top.c:552 (gdb+0x94adde) #20 command_line_handler(std::unique_ptr<char, gdb::xfree_deleter<char> >&&) gdb/event-top.c:788 (gdb+0x94b49b) #21 tui_command_line_handler gdb/tui/tui-interp.c:104 (gdb+0x103479c) #22 gdb_rl_callback_handler gdb/event-top.c:259 (gdb+0x94a383) #23 rl_callback_read_char readline/readline/callback.c:290 (gdb+0x11bde5d) #24 gdb_rl_callback_read_char_wrapper_noexcept gdb/event-top.c:195 (gdb+0x94a182) #25 gdb_rl_callback_read_char_wrapper gdb/event-top.c:234 (gdb+0x94a243) #26 stdin_event_handler gdb/ui.c:155 (gdb+0x1074a40) #27 handle_file_event gdbsupport/event-loop.cc:573 (gdb+0x1d94f02) #28 gdb_wait_for_event gdbsupport/event-loop.cc:694 (gdb+0x1d9563a) #29 gdb_do_one_event(int) gdbsupport/event-loop.cc:264 (gdb+0x1d93a26) #30 start_event_loop gdb/main.c:412 (gdb+0xb5a374) #31 captured_command_loop gdb/main.c:476 (gdb+0xb5a563) #32 captured_main gdb/main.c:1320 (gdb+0xb5c6e3) #33 gdb_main(captured_main_args*) gdb/main.c:1339 (gdb+0xb5c792) #34 main gdb/gdb.c:32 (gdb+0x416776) Previous read of size 1 at 0x7b4400097d08 by thread T12: #0 bfd_check_format_matches bfd/format.c:323 (gdb+0x1492db4) #1 bfd_check_format bfd/format.c:94 (gdb+0x1492104) #2 build_id_bfd_get(bfd*) gdb/build-id.c:42 (gdb+0x6648f7) bminor#3 index_cache::store(dwarf2_per_bfd*, index_cache_store_context*) gdb/dwarf2/index-cache.c:110 (gdb+0x82d205) bminor#4 cooked_index::maybe_write_index(dwarf2_per_bfd*) gdb/dwarf2/cooked-index.c:640 (gdb+0x7f1bf1) bminor#5 operator() gdb/dwarf2/cooked-index.c:470 (gdb+0x7f0f40) bminor#6 _M_invoke /usr/include/c++/7/bits/std_function.h:316 (gdb+0x7f28f7) bminor#7 std::function<void ()>::operator()() const /usr/include/c++/7/bits/std_function.h:706 (gdb+0x700952) bminor#8 void std::__invoke_impl<void, std::function<void ()>&>(std::__invoke_other, std::function<void ()>&) /usr/include/c++/7/bits/invoke.h:60 (gdb+0x7381a0) bminor#9 std::__invoke_result<std::function<void ()>&>::type std::__invoke<std::function<void ()>&>(std::function<void ()>&) /usr/include/c++/7/bits/invoke.h:95 (gdb+0x737e91) bminor#10 std::__future_base::_Task_state<std::function<void ()>, std::allocator<int>, void ()>::_M_run()::{lambda()#1}::operator()() const /usr/include/c++/7/future:1421 (gdb+0x737b59) bminor#11 std::__future_base::_Task_setter<std::unique_ptr<std::__future_base::_Result<void>, std::__future_base::_Result_base::_Deleter>, std::__future_base::_Task_state<std::function<void ()>, std::allocator<int>, void ()>::_M_run()::{lambda()#1}, void>::operator()() const /usr/include/c++/7/future:1362 (gdb+0x738660) bminor#12 std::_Function_handler<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> (), std::__future_base::_Task_setter<std::unique_ptr<std::__future_base::_Result<void>, std::__future_base::_Result_base::_Deleter>, std::__future_base::_Task_state<std::function<void ()>, std::allocator<int>, void ()>::_M_run()::{lambda()#1}, void> >::_M_invoke(std::_Any_data const&) /usr/include/c++/7/bits/std_function.h:302 (gdb+0x73825c) #13 std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>::operator()() const /usr/include/c++/7/bits/std_function.h:706 (gdb+0x733623) #14 std::__future_base::_State_baseV2::_M_do_set(std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*) /usr/include/c++/7/future:561 (gdb+0x732bdf) #15 void std::__invoke_impl<void, void (std::__future_base::_State_baseV2::*)(std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*), std::__future_base::_State_baseV2*, std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*>(std::__invoke_memfun_deref, void (std::__future_base::_State_baseV2::*&&)(std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*), std::__future_base::_State_baseV2*&&, std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*&&, bool*&&) /usr/include/c++/7/bits/invoke.h:73 (gdb+0x734c4f) #16 std::__invoke_result<void (std::__future_base::_State_baseV2::*)(std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*), std::__future_base::_State_baseV2*, std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*>::type std::__invoke<void (std::__future_base::_State_baseV2::*)(std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*), std::__future_base::_State_baseV2*, std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*>(void (std::__future_base::_State_baseV2::*&&)(std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*), std::__future_base::_State_baseV2*&&, std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*&&, bool*&&) /usr/include/c++/7/bits/invoke.h:95 (gdb+0x733bc5) #17 std::call_once<void (std::__future_base::_State_baseV2::*)(std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*), std::__future_base::_State_baseV2*, std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*>(std::once_flag&, void (std::__future_base::_State_baseV2::*&&)(std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*), std::__future_base::_State_baseV2*&&, std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*&&, bool*&&)::{lambda()#1}::operator()() const /usr/include/c++/7/mutex:672 (gdb+0x73300d) #18 std::call_once<void (std::__future_base::_State_baseV2::*)(std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*), std::__future_base::_State_baseV2*, std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*>(std::once_flag&, void (std::__future_base::_State_baseV2::*&&)(std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*), std::__future_base::_State_baseV2*&&, std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*&&, bool*&&)::{lambda()#2}::operator()() const /usr/include/c++/7/mutex:677 (gdb+0x7330b2) #19 std::call_once<void (std::__future_base::_State_baseV2::*)(std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*), std::__future_base::_State_baseV2*, std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*>(std::once_flag&, void (std::__future_base::_State_baseV2::*&&)(std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*), std::__future_base::_State_baseV2*&&, std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*&&, bool*&&)::{lambda()#2}::_FUN() /usr/include/c++/7/mutex:677 (gdb+0x7330f2) #20 pthread_once <null> (libtsan.so.0+0x4457c) #21 __gthread_once /usr/include/c++/7/x86_64-suse-linux/bits/gthr-default.h:699 (gdb+0x72f5dd) #22 void std::call_once<void (std::__future_base::_State_baseV2::*)(std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*), std::__future_base::_State_baseV2*, std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*>(std::once_flag&, void (std::__future_base::_State_baseV2::*&&)(std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*), std::__future_base::_State_baseV2*&&, std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*&&, bool*&&) /usr/include/c++/7/mutex:684 (gdb+0x733224) #23 std::__future_base::_State_baseV2::_M_set_result(std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>, bool) /usr/include/c++/7/future:401 (gdb+0x732852) #24 std::__future_base::_Task_state<std::function<void ()>, std::allocator<int>, void ()>::_M_run() /usr/include/c++/7/future:1423 (gdb+0x737bef) #25 std::packaged_task<void ()>::operator()() /usr/include/c++/7/future:1556 (gdb+0x1dac5b0) #26 gdb::thread_pool::thread_function() gdbsupport/thread-pool.cc:242 (gdb+0x1dabed2) #27 void std::__invoke_impl<void, void (gdb::thread_pool::*)(), gdb::thread_pool*>(std::__invoke_memfun_deref, void (gdb::thread_pool::*&&)(), gdb::thread_pool*&&) /usr/include/c++/7/bits/invoke.h:73 (gdb+0x1dacf81) #28 std::__invoke_result<void (gdb::thread_pool::*)(), gdb::thread_pool*>::type std::__invoke<void (gdb::thread_pool::*)(), gdb::thread_pool*>(void (gdb::thread_pool::*&&)(), gdb::thread_pool*&&) /usr/include/c++/7/bits/invoke.h:95 (gdb+0x1dac3b2) #29 decltype (__invoke((_S_declval<0ul>)(), (_S_declval<1ul>)())) std::thread::_Invoker<std::tuple<void (gdb::thread_pool::*)(), gdb::thread_pool*> >::_M_invoke<0ul, 1ul>(std::_Index_tuple<0ul, 1ul>) /usr/include/c++/7/thread:234 (gdb+0x1daf6e4) #30 std::thread::_Invoker<std::tuple<void (gdb::thread_pool::*)(), gdb::thread_pool*> >::operator()() /usr/include/c++/7/thread:243 (gdb+0x1daf66f) #31 std::thread::_State_impl<std::thread::_Invoker<std::tuple<void (gdb::thread_pool::*)(), gdb::thread_pool*> > >::_M_run() /usr/include/c++/7/thread:186 (gdb+0x1daf624) #32 <null> <null> (libstdc++.so.6+0xdcac2) ... SUMMARY: ThreadSanitizer: data race bfd/cache.c:584 in bfd_open_file ... The race happens when issuing the "file $exec" command. The race is between: - a worker thread getting the build id while writing the index cache, and in the process reading bfd::format, and - the main thread calling find_main_name, and in the process setting bfd::cacheable. The two bitfields bfd::cacheable and bfd::format share the same bitfield container. Fix this by capturing the build id in the main thread, and using the captured value in the worker thread. Likewise for the dwz build id, which likely suffers from the same issue. While we're at it, also move the creation of the cache directory to the index_cache_store_context constructor, to: - make sure there's no race between subsequent file commands, and - issue any related warning or error messages during the file command. Tested on x86_64-linux. Approved-By: Tom Tromey <tom@tromey.com> PR symtab/30392 Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=30392

With gdb build with -fsanitize=thread and test-case gdb.base/index-cache.exp I run into: ... (gdb) file build/gdb/testsuite/outputs/gdb.base/index-cache/index-cache Reading symbols from build/gdb/testsuite/outputs/gdb.base/index-cache/index-cache... ================== WARNING: ThreadSanitizer: data race (pid=24296) Write of size 1 at 0x7b200000420d by main thread: #0 queue_comp_unit gdb/dwarf2/read.c:5564 (gdb+0x8939ce) #1 dw2_do_instantiate_symtab gdb/dwarf2/read.c:1754 (gdb+0x885b96) #2 dw2_instantiate_symtab gdb/dwarf2/read.c:1792 (gdb+0x885d86) bminor#3 dw2_expand_symtabs_matching_one(dwarf2_per_cu_data*, dwarf2_per_objfile*, gdb::function_view<bool (char const*, bool)>, gdb::function_view<bool (compunit_symtab*)>) gdb/dwarf2/read.c:3042 (gdb+0x88ac77) bminor#4 cooked_index_functions::expand_symtabs_matching(objfile*, gdb::function_view<bool (char const*, bool)>, lookup_name_info const*, gdb::function_view<bool (char const*)>, gdb::function_view<bool (compunit_symtab*)>, enum_flags<block_search_flag_values>, domain_enum, search_domain) gdb/dwarf2/read.c:16915 (gdb+0x8c1c8a) bminor#5 objfile::lookup_symbol(block_enum, char const*, domain_enum) gdb/symfile-debug.c:288 (gdb+0xf389a1) bminor#6 lookup_symbol_via_quick_fns gdb/symtab.c:2385 (gdb+0xf66403) bminor#7 lookup_symbol_in_objfile gdb/symtab.c:2516 (gdb+0xf66a67) bminor#8 operator() gdb/symtab.c:2562 (gdb+0xf66bbe) bminor#9 operator() gdb/../gdbsupport/function-view.h:305 (gdb+0xf76ffd) bminor#10 _FUN gdb/../gdbsupport/function-view.h:299 (gdb+0xf77054) bminor#11 gdb::function_view<bool (objfile*)>::operator()(objfile*) const gdb/../gdbsupport/function-view.h:289 (gdb+0xc3f5e3) bminor#12 svr4_iterate_over_objfiles_in_search_order gdb/solib-svr4.c:3455 (gdb+0xeca793) #13 gdbarch_iterate_over_objfiles_in_search_order(gdbarch*, gdb::function_view<bool (objfile*)>, objfile*) gdb/gdbarch.c:5041 (gdb+0x537cad) #14 lookup_global_or_static_symbol gdb/symtab.c:2559 (gdb+0xf66e47) #15 lookup_global_symbol(char const*, block const*, domain_enum) gdb/symtab.c:2615 (gdb+0xf670cc) #16 language_defn::lookup_symbol_nonlocal(char const*, block const*, domain_enum) const gdb/symtab.c:2447 (gdb+0xf666ba) #17 lookup_symbol_aux gdb/symtab.c:2123 (gdb+0xf655ff) #18 lookup_symbol_in_language(char const*, block const*, domain_enum, language, field_of_this_result*) gdb/symtab.c:1931 (gdb+0xf646f7) #19 set_initial_language() gdb/symfile.c:1708 (gdb+0xf429c0) #20 symbol_file_add_main_1 gdb/symfile.c:1212 (gdb+0xf40f54) #21 symbol_file_command(char const*, int) gdb/symfile.c:1681 (gdb+0xf428fb) #22 file_command gdb/exec.c:554 (gdb+0x94f875) #23 do_simple_func gdb/cli/cli-decode.c:95 (gdb+0x6d9528) #24 cmd_func(cmd_list_element*, char const*, int) gdb/cli/cli-decode.c:2735 (gdb+0x6e0f69) #25 execute_command(char const*, int) gdb/top.c:575 (gdb+0xff3166) #26 command_handler(char const*) gdb/event-top.c:552 (gdb+0x94af08) #27 command_line_handler(std::unique_ptr<char, gdb::xfree_deleter<char> >&&) gdb/event-top.c:788 (gdb+0x94b5c5) #28 tui_command_line_handler gdb/tui/tui-interp.c:104 (gdb+0x10348c6) #29 gdb_rl_callback_handler gdb/event-top.c:259 (gdb+0x94a4ad) #30 rl_callback_read_char readline/readline/callback.c:290 (gdb+0x11bdf87) #31 gdb_rl_callback_read_char_wrapper_noexcept gdb/event-top.c:195 (gdb+0x94a2ac) #32 gdb_rl_callback_read_char_wrapper gdb/event-top.c:234 (gdb+0x94a36d) #33 stdin_event_handler gdb/ui.c:155 (gdb+0x1074b6a) #34 handle_file_event gdbsupport/event-loop.cc:573 (gdb+0x1d9502c) #35 gdb_wait_for_event gdbsupport/event-loop.cc:694 (gdb+0x1d95764) #36 gdb_do_one_event(int) gdbsupport/event-loop.cc:264 (gdb+0x1d93b50) #37 start_event_loop gdb/main.c:412 (gdb+0xb5a49e) #38 captured_command_loop gdb/main.c:476 (gdb+0xb5a68d) #39 captured_main gdb/main.c:1320 (gdb+0xb5c80d) #40 gdb_main(captured_main_args*) gdb/main.c:1339 (gdb+0xb5c8bc) #41 main gdb/gdb.c:32 (gdb+0x416776) Previous read of size 1 at 0x7b200000420d by thread T12: #0 write_gdbindex gdb/dwarf2/index-write.c:1229 (gdb+0x8310c8) #1 write_dwarf_index(dwarf2_per_bfd*, char const*, char const*, char const*, dw_index_kind) gdb/dwarf2/index-write.c:1484 (gdb+0x83232f) #2 index_cache::store(dwarf2_per_bfd*, index_cache_store_context*) gdb/dwarf2/index-cache.c:177 (gdb+0x82d62b) bminor#3 cooked_index::maybe_write_index(dwarf2_per_bfd*) gdb/dwarf2/cooked-index.c:640 (gdb+0x7f1bf7) bminor#4 operator() gdb/dwarf2/cooked-index.c:470 (gdb+0x7f0f40) bminor#5 _M_invoke /usr/include/c++/7/bits/std_function.h:316 (gdb+0x7f2909) bminor#6 std::function<void ()>::operator()() const /usr/include/c++/7/bits/std_function.h:706 (gdb+0x700952) bminor#7 void std::__invoke_impl<void, std::function<void ()>&>(std::__invoke_other, std::function<void ()>&) /usr/include/c++/7/bits/invoke.h:60 (gdb+0x7381a0) bminor#8 std::__invoke_result<std::function<void ()>&>::type std::__invoke<std::function<void ()>&>(std::function<void ()>&) /usr/include/c++/7/bits/invoke.h:95 (gdb+0x737e91) bminor#9 std::__future_base::_Task_state<std::function<void ()>, std::allocator<int>, void ()>::_M_run()::{lambda()#1}::operator()() const /usr/include/c++/7/future:1421 (gdb+0x737b59) bminor#10 std::__future_base::_Task_setter<std::unique_ptr<std::__future_base::_Result<void>, std::__future_base::_Result_base::_Deleter>, std::__future_base::_Task_state<std::function<void ()>, std::allocator<int>, void ()>::_M_run()::{lambda()#1}, void>::operator()() const /usr/include/c++/7/future:1362 (gdb+0x738660) bminor#11 std::_Function_handler<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> (), std::__future_base::_Task_setter<std::unique_ptr<std::__future_base::_Result<void>, std::__future_base::_Result_base::_Deleter>, std::__future_base::_Task_state<std::function<void ()>, std::allocator<int>, void ()>::_M_run()::{lambda()#1}, void> >::_M_invoke(std::_Any_data const&) /usr/include/c++/7/bits/std_function.h:302 (gdb+0x73825c) bminor#12 std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>::operator()() const /usr/include/c++/7/bits/std_function.h:706 (gdb+0x733623) #13 std::__future_base::_State_baseV2::_M_do_set(std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*) /usr/include/c++/7/future:561 (gdb+0x732bdf) #14 void std::__invoke_impl<void, void (std::__future_base::_State_baseV2::*)(std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*), std::__future_base::_State_baseV2*, std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*>(std::__invoke_memfun_deref, void (std::__future_base::_State_baseV2::*&&)(std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*), std::__future_base::_State_baseV2*&&, std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*&&, bool*&&) /usr/include/c++/7/bits/invoke.h:73 (gdb+0x734c4f) #15 std::__invoke_result<void (std::__future_base::_State_baseV2::*)(std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*), std::__future_base::_State_baseV2*, std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*>::type std::__invoke<void (std::__future_base::_State_baseV2::*)(std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*), std::__future_base::_State_baseV2*, std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*>(void (std::__future_base::_State_baseV2::*&&)(std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*), std::__future_base::_State_baseV2*&&, std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*&&, bool*&&) /usr/include/c++/7/bits/invoke.h:95 (gdb+0x733bc5) #16 std::call_once<void (std::__future_base::_State_baseV2::*)(std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*), std::__future_base::_State_baseV2*, std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*>(std::once_flag&, void (std::__future_base::_State_baseV2::*&&)(std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*), std::__future_base::_State_baseV2*&&, std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*&&, bool*&&)::{lambda()#1}::operator()() const /usr/include/c++/7/mutex:672 (gdb+0x73300d) #17 std::call_once<void (std::__future_base::_State_baseV2::*)(std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*), std::__future_base::_State_baseV2*, std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*>(std::once_flag&, void (std::__future_base::_State_baseV2::*&&)(std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*), std::__future_base::_State_baseV2*&&, std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*&&, bool*&&)::{lambda()#2}::operator()() const /usr/include/c++/7/mutex:677 (gdb+0x7330b2) #18 std::call_once<void (std::__future_base::_State_baseV2::*)(std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*), std::__future_base::_State_baseV2*, std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*>(std::once_flag&, void (std::__future_base::_State_baseV2::*&&)(std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*), std::__future_base::_State_baseV2*&&, std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*&&, bool*&&)::{lambda()#2}::_FUN() /usr/include/c++/7/mutex:677 (gdb+0x7330f2) #19 pthread_once <null> (libtsan.so.0+0x4457c) #20 __gthread_once /usr/include/c++/7/x86_64-suse-linux/bits/gthr-default.h:699 (gdb+0x72f5dd) #21 void std::call_once<void (std::__future_base::_State_baseV2::*)(std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*), std::__future_base::_State_baseV2*, std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*>(std::once_flag&, void (std::__future_base::_State_baseV2::*&&)(std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*), std::__future_base::_State_baseV2*&&, std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*&&, bool*&&) /usr/include/c++/7/mutex:684 (gdb+0x733224) #22 std::__future_base::_State_baseV2::_M_set_result(std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>, bool) /usr/include/c++/7/future:401 (gdb+0x732852) #23 std::__future_base::_Task_state<std::function<void ()>, std::allocator<int>, void ()>::_M_run() /usr/include/c++/7/future:1423 (gdb+0x737bef) #24 std::packaged_task<void ()>::operator()() /usr/include/c++/7/future:1556 (gdb+0x1dac6da) #25 gdb::thread_pool::thread_function() gdbsupport/thread-pool.cc:242 (gdb+0x1dabffc) #26 void std::__invoke_impl<void, void (gdb::thread_pool::*)(), gdb::thread_pool*>(std::__invoke_memfun_deref, void (gdb::thread_pool::*&&)(), gdb::thread_pool*&&) /usr/include/c++/7/bits/invoke.h:73 (gdb+0x1dad0ab) #27 std::__invoke_result<void (gdb::thread_pool::*)(), gdb::thread_pool*>::type std::__invoke<void (gdb::thread_pool::*)(), gdb::thread_pool*>(void (gdb::thread_pool::*&&)(), gdb::thread_pool*&&) /usr/include/c++/7/bits/invoke.h:95 (gdb+0x1dac4dc) #28 decltype (__invoke((_S_declval<0ul>)(), (_S_declval<1ul>)())) std::thread::_Invoker<std::tuple<void (gdb::thread_pool::*)(), gdb::thread_pool*> >::_M_invoke<0ul, 1ul>(std::_Index_tuple<0ul, 1ul>) /usr/include/c++/7/thread:234 (gdb+0x1daf80e) #29 std::thread::_Invoker<std::tuple<void (gdb::thread_pool::*)(), gdb::thread_pool*> >::operator()() /usr/include/c++/7/thread:243 (gdb+0x1daf799) #30 std::thread::_State_impl<std::thread::_Invoker<std::tuple<void (gdb::thread_pool::*)(), gdb::thread_pool*> > >::_M_run() /usr/include/c++/7/thread:186 (gdb+0x1daf74e) #31 <null> <null> (libstdc++.so.6+0xdcac2) ... SUMMARY: ThreadSanitizer: data race gdb/dwarf2/read.c:5564 in queue_comp_unit ... The race happens when issuing the "file $exec" command. The race is between: - a worker thread writing the index cache, and in the process reading dwarf2_per_cu_data::is_debug_type, and - the main thread expanding the CU containing main, and in the process setting dwarf2_per_cu_data::queued. The two bitfields dwarf2_per_cu_data::queue and dwarf2_per_cu_data::is_debug_type share the same bitfield container. Fix this by making dwarf2_per_cu_data::queued a packed<bool, 1>. Tested on x86_64-linux. Approved-By: Tom Tromey <tom@tromey.com> PR symtab/30392 Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=30392

…s_debug_type} With gdb build with -fsanitize=thread and test-case gdb.base/index-cache.exp and target board debug-types, I run into: ... (gdb) file build/gdb/testsuite/outputs/gdb.base/index-cache/index-cache Reading symbols from build/gdb/testsuite/outputs/gdb.base/index-cache/index-cache... ================== WARNING: ThreadSanitizer: data race (pid=9654) Write of size 1 at 0x7b200000420d by main thread: #0 dwarf2_per_cu_data::get_header() const gdb/dwarf2/read.c:21513 (gdb+0x8d1eee) #1 dwarf2_per_cu_data::addr_size() const gdb/dwarf2/read.c:21524 (gdb+0x8d1f4e) #2 dwarf2_cu::addr_type() const gdb/dwarf2/cu.c:112 (gdb+0x806327) bminor#3 set_die_type gdb/dwarf2/read.c:21932 (gdb+0x8d3870) bminor#4 read_base_type gdb/dwarf2/read.c:15448 (gdb+0x8bcacb) bminor#5 read_type_die_1 gdb/dwarf2/read.c:19832 (gdb+0x8cc0a5) bminor#6 read_type_die gdb/dwarf2/read.c:19767 (gdb+0x8cbe6d) bminor#7 lookup_die_type gdb/dwarf2/read.c:19739 (gdb+0x8cbdc7) bminor#8 die_type gdb/dwarf2/read.c:19593 (gdb+0x8cb68a) bminor#9 read_subroutine_type gdb/dwarf2/read.c:14648 (gdb+0x8b998e) bminor#10 read_type_die_1 gdb/dwarf2/read.c:19792 (gdb+0x8cbf2f) bminor#11 read_type_die gdb/dwarf2/read.c:19767 (gdb+0x8cbe6d) bminor#12 read_func_scope gdb/dwarf2/read.c:10154 (gdb+0x8a4f36) #13 process_die gdb/dwarf2/read.c:6667 (gdb+0x898daa) #14 read_file_scope gdb/dwarf2/read.c:7682 (gdb+0x89bad8) #15 process_die gdb/dwarf2/read.c:6654 (gdb+0x898ced) #16 process_full_comp_unit gdb/dwarf2/read.c:6418 (gdb+0x8981de) #17 process_queue gdb/dwarf2/read.c:5690 (gdb+0x894433) #18 dw2_do_instantiate_symtab gdb/dwarf2/read.c:1770 (gdb+0x88623a) #19 dw2_instantiate_symtab gdb/dwarf2/read.c:1792 (gdb+0x886300) #20 dw2_expand_symtabs_matching_one(dwarf2_per_cu_data*, dwarf2_per_objfile*, gdb::function_view<bool (char const*, bool)>, gdb::function_view<bool (compunit_symtab*)>) gdb/dwarf2/read.c:3042 (gdb+0x88b1f1) #21 cooked_index_functions::expand_symtabs_matching(objfile*, gdb::function_view<bool (char const*, bool)>, lookup_name_info const*, gdb::function_view<bool (char const*)>, gdb::function_view<bool (compunit_symtab*)>, enum_flags<block_search_flag_values>, domain_enum, search_domain) gdb/dwarf2/read.c:16917 (gdb+0x8c228e) #22 objfile::lookup_symbol(block_enum, char const*, domain_enum) gdb/symfile-debug.c:288 (gdb+0xf39055) #23 lookup_symbol_via_quick_fns gdb/symtab.c:2385 (gdb+0xf66ab7) #24 lookup_symbol_in_objfile gdb/symtab.c:2516 (gdb+0xf6711b) #25 operator() gdb/symtab.c:2562 (gdb+0xf67272) #26 operator() gdb/../gdbsupport/function-view.h:305 (gdb+0xf776b1) #27 _FUN gdb/../gdbsupport/function-view.h:299 (gdb+0xf77708) #28 gdb::function_view<bool (objfile*)>::operator()(objfile*) const gdb/../gdbsupport/function-view.h:289 (gdb+0xc3fc97) #29 svr4_iterate_over_objfiles_in_search_order gdb/solib-svr4.c:3455 (gdb+0xecae47) #30 gdbarch_iterate_over_objfiles_in_search_order(gdbarch*, gdb::function_view<bool (objfile*)>, objfile*) gdb/gdbarch.c:5041 (gdb+0x537cad) #31 lookup_global_or_static_symbol gdb/symtab.c:2559 (gdb+0xf674fb) #32 lookup_global_symbol(char const*, block const*, domain_enum) gdb/symtab.c:2615 (gdb+0xf67780) #33 language_defn::lookup_symbol_nonlocal(char const*, block const*, domain_enum) const gdb/symtab.c:2447 (gdb+0xf66d6e) #34 lookup_symbol_aux gdb/symtab.c:2123 (gdb+0xf65cb3) #35 lookup_symbol_in_language(char const*, block const*, domain_enum, language, field_of_this_result*) gdb/symtab.c:1931 (gdb+0xf64dab) #36 set_initial_language() gdb/symfile.c:1708 (gdb+0xf43074) #37 symbol_file_add_main_1 gdb/symfile.c:1212 (gdb+0xf41608) #38 symbol_file_command(char const*, int) gdb/symfile.c:1681 (gdb+0xf42faf) #39 file_command gdb/exec.c:554 (gdb+0x94ff29) #40 do_simple_func gdb/cli/cli-decode.c:95 (gdb+0x6d9528) #41 cmd_func(cmd_list_element*, char const*, int) gdb/cli/cli-decode.c:2735 (gdb+0x6e0f69) #42 execute_command(char const*, int) gdb/top.c:575 (gdb+0xff379c) #43 command_handler(char const*) gdb/event-top.c:552 (gdb+0x94b5bc) #44 command_line_handler(std::unique_ptr<char, gdb::xfree_deleter<char> >&&) gdb/event-top.c:788 (gdb+0x94bc79) #45 tui_command_line_handler gdb/tui/tui-interp.c:104 (gdb+0x1034efc) #46 gdb_rl_callback_handler gdb/event-top.c:259 (gdb+0x94ab61) #47 rl_callback_read_char readline/readline/callback.c:290 (gdb+0x11be4ef) #48 gdb_rl_callback_read_char_wrapper_noexcept gdb/event-top.c:195 (gdb+0x94a960) #49 gdb_rl_callback_read_char_wrapper gdb/event-top.c:234 (gdb+0x94aa21) #50 stdin_event_handler gdb/ui.c:155 (gdb+0x10751a0) #51 handle_file_event gdbsupport/event-loop.cc:573 (gdb+0x1d95bac) #52 gdb_wait_for_event gdbsupport/event-loop.cc:694 (gdb+0x1d962e4) #53 gdb_do_one_event(int) gdbsupport/event-loop.cc:264 (gdb+0x1d946d0) #54 start_event_loop gdb/main.c:412 (gdb+0xb5ab52) #55 captured_command_loop gdb/main.c:476 (gdb+0xb5ad41) #56 captured_main gdb/main.c:1320 (gdb+0xb5cec1) #57 gdb_main(captured_main_args*) gdb/main.c:1339 (gdb+0xb5cf70) #58 main gdb/gdb.c:32 (gdb+0x416776) Previous read of size 1 at 0x7b200000420d by thread T11: #0 write_gdbindex gdb/dwarf2/index-write.c:1229 (gdb+0x831630) #1 write_dwarf_index(dwarf2_per_bfd*, char const*, char const*, char const*, dw_index_kind) gdb/dwarf2/index-write.c:1484 (gdb+0x832897) #2 index_cache::store(dwarf2_per_bfd*, index_cache_store_context const&) gdb/dwarf2/index-cache.c:173 (gdb+0x82db8d) bminor#3 cooked_index::maybe_write_index(dwarf2_per_bfd*, index_cache_store_context const&) gdb/dwarf2/cooked-index.c:645 (gdb+0x7f1d49) bminor#4 operator() gdb/dwarf2/cooked-index.c:474 (gdb+0x7f0f31) bminor#5 _M_invoke /usr/include/c++/7/bits/std_function.h:316 (gdb+0x7f2a13) bminor#6 std::function<void ()>::operator()() const /usr/include/c++/7/bits/std_function.h:706 (gdb+0x700952) bminor#7 void std::__invoke_impl<void, std::function<void ()>&>(std::__invoke_other, std::function<void ()>&) /usr/include/c++/7/bits/invoke.h:60 (gdb+0x7381a0) bminor#8 std::__invoke_result<std::function<void ()>&>::type std::__invoke<std::function<void ()>&>(std::function<void ()>&) /usr/include/c++/7/bits/invoke.h:95 (gdb+0x737e91) bminor#9 std::__future_base::_Task_state<std::function<void ()>, std::allocator<int>, void ()>::_M_run()::{lambda()#1}::operator()() const /usr/include/c++/7/future:1421 (gdb+0x737b59) bminor#10 std::__future_base::_Task_setter<std::unique_ptr<std::__future_base::_Result<void>, std::__future_base::_Result_base::_Deleter>, std::__future_base::_Task_state<std::function<void ()>, std::allocator<int>, void ()>::_M_run()::{lambda()#1}, void>::operator()() const /usr/include/c++/7/future:1362 (gdb+0x738660) bminor#11 std::_Function_handler<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> (), std::__future_base::_Task_setter<std::unique_ptr<std::__future_base::_Result<void>, std::__future_base::_Result_base::_Deleter>, std::__future_base::_Task_state<std::function<void ()>, std::allocator<int>, void ()>::_M_run()::{lambda()#1}, void> >::_M_invoke(std::_Any_data const&) /usr/include/c++/7/bits/std_function.h:302 (gdb+0x73825c) bminor#12 std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>::operator()() const /usr/include/c++/7/bits/std_function.h:706 (gdb+0x733623) #13 std::__future_base::_State_baseV2::_M_do_set(std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*) /usr/include/c++/7/future:561 (gdb+0x732bdf) #14 void std::__invoke_impl<void, void (std::__future_base::_State_baseV2::*)(std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*), std::__future_base::_State_baseV2*, std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*>(std::__invoke_memfun_deref, void (std::__future_base::_State_baseV2::*&&)(std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*), std::__future_base::_State_baseV2*&&, std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*&&, bool*&&) /usr/include/c++/7/bits/invoke.h:73 (gdb+0x734c4f) #15 std::__invoke_result<void (std::__future_base::_State_baseV2::*)(std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*), std::__future_base::_State_baseV2*, std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*>::type std::__invoke<void (std::__future_base::_State_baseV2::*)(std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*), std::__future_base::_State_baseV2*, std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*>(void (std::__future_base::_State_baseV2::*&&)(std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*), std::__future_base::_State_baseV2*&&, std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*&&, bool*&&) /usr/include/c++/7/bits/invoke.h:95 (gdb+0x733bc5) #16 std::call_once<void (std::__future_base::_State_baseV2::*)(std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*), std::__future_base::_State_baseV2*, std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*>(std::once_flag&, void (std::__future_base::_State_baseV2::*&&)(std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*), std::__future_base::_State_baseV2*&&, std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*&&, bool*&&)::{lambda()#1}::operator()() const /usr/include/c++/7/mutex:672 (gdb+0x73300d) #17 std::call_once<void (std::__future_base::_State_baseV2::*)(std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*), std::__future_base::_State_baseV2*, std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*>(std::once_flag&, void (std::__future_base::_State_baseV2::*&&)(std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*), std::__future_base::_State_baseV2*&&, std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*&&, bool*&&)::{lambda()#2}::operator()() const /usr/include/c++/7/mutex:677 (gdb+0x7330b2) #18 std::call_once<void (std::__future_base::_State_baseV2::*)(std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*), std::__future_base::_State_baseV2*, std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*>(std::once_flag&, void (std::__future_base::_State_baseV2::*&&)(std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*), std::__future_base::_State_baseV2*&&, std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*&&, bool*&&)::{lambda()#2}::_FUN() /usr/include/c++/7/mutex:677 (gdb+0x7330f2) #19 pthread_once <null> (libtsan.so.0+0x4457c) #20 __gthread_once /usr/include/c++/7/x86_64-suse-linux/bits/gthr-default.h:699 (gdb+0x72f5dd) #21 void std::call_once<void (std::__future_base::_State_baseV2::*)(std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*), std::__future_base::_State_baseV2*, std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*>(std::once_flag&, void (std::__future_base::_State_baseV2::*&&)(std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*), std::__future_base::_State_baseV2*&&, std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*&&, bool*&&) /usr/include/c++/7/mutex:684 (gdb+0x733224) #22 std::__future_base::_State_baseV2::_M_set_result(std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>, bool) /usr/include/c++/7/future:401 (gdb+0x732852) #23 std::__future_base::_Task_state<std::function<void ()>, std::allocator<int>, void ()>::_M_run() /usr/include/c++/7/future:1423 (gdb+0x737bef) #24 std::packaged_task<void ()>::operator()() /usr/include/c++/7/future:1556 (gdb+0x1dad25a) #25 gdb::thread_pool::thread_function() gdbsupport/thread-pool.cc:242 (gdb+0x1dacb7c) #26 void std::__invoke_impl<void, void (gdb::thread_pool::*)(), gdb::thread_pool*>(std::__invoke_memfun_deref, void (gdb::thread_pool::*&&)(), gdb::thread_pool*&&) /usr/include/c++/7/bits/invoke.h:73 (gdb+0x1dadc2b) #27 std::__invoke_result<void (gdb::thread_pool::*)(), gdb::thread_pool*>::type std::__invoke<void (gdb::thread_pool::*)(), gdb::thread_pool*>(void (gdb::thread_pool::*&&)(), gdb::thread_pool*&&) /usr/include/c++/7/bits/invoke.h:95 (gdb+0x1dad05c) #28 decltype (__invoke((_S_declval<0ul>)(), (_S_declval<1ul>)())) std::thread::_Invoker<std::tuple<void (gdb::thread_pool::*)(), gdb::thread_pool*> >::_M_invoke<0ul, 1ul>(std::_Index_tuple<0ul, 1ul>) /usr/include/c++/7/thread:234 (gdb+0x1db038e) #29 std::thread::_Invoker<std::tuple<void (gdb::thread_pool::*)(), gdb::thread_pool*> >::operator()() /usr/include/c++/7/thread:243 (gdb+0x1db0319) #30 std::thread::_State_impl<std::thread::_Invoker<std::tuple<void (gdb::thread_pool::*)(), gdb::thread_pool*> > >::_M_run() /usr/include/c++/7/thread:186 (gdb+0x1db02ce) #31 <null> <null> (libstdc++.so.6+0xdcac2) ... SUMMARY: ThreadSanitizer: data race gdb/dwarf2/read.c:21513 in dwarf2_per_cu_data::get_header() const ... The race happens when issuing the "file $exec" command. The race is between: - a worker thread writing the index cache, and in the process reading dwarf2_per_cu_data::is_debug_type, and - the main thread writing to dwarf2_per_cu_data::m_header_read_in. The two bitfields dwarf2_per_cu_data::m_header_read_in and dwarf2_per_cu_data::is_debug_type share the same bitfield container. Fix this by making dwarf2_per_cu_data::m_header_read_in a packed<bool, 1>. Tested on x86_64-linux. Approved-By: Tom Tromey <tom@tromey.com> PR symtab/30392 Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=30392

With gdb build with -fsanitize=thread, and the exec from test-case gdb.base/index-cache.exp, I run into: ... $ rm -f ~/.cache/gdb/*; \ gdb -q -batch -iex "set index-cache enabled on" index-cache \ -ex "print foobar" ... WARNING: ThreadSanitizer: data race (pid=23970) Write of size 1 at 0x7b200000410d by main thread: #0 dw_expand_symtabs_matching_file_matcher(dwarf2_per_objfile*, gdb::function_view<bool (char const*, bool)>) gdb/dwarf2/read.c:3077 (gdb+0x7ac54e) #1 cooked_index_functions::expand_symtabs_matching(objfile*, gdb::function_view<bool (char const*, bool)>, lookup_name_info const*, gdb::function_view<bool (char const*)>, gdb::function_view<bool (compunit_symtab*)>, enum_flags<block_search_flag_values>, domain_enum, search_domain) gdb/dwarf2/read.c:16812 (gdb+0x7d039f) #2 objfile::map_symtabs_matching_filename(char const*, char const*, gdb::function_view<bool (symtab*)>) gdb/symfile-debug.c:219 (gdb+0xda5aee) bminor#3 iterate_over_symtabs(char const*, gdb::function_view<bool (symtab*)>) gdb/symtab.c:648 (gdb+0xdc439d) bminor#4 lookup_symtab(char const*) gdb/symtab.c:662 (gdb+0xdc44a2) bminor#5 classify_name gdb/c-exp.y:3083 (gdb+0x61afec) bminor#6 c_yylex gdb/c-exp.y:3251 (gdb+0x61dd13) bminor#7 c_yyparse() build/gdb/c-exp.c.tmp:1988 (gdb+0x61f07e) bminor#8 c_parse(parser_state*) gdb/c-exp.y:3417 (gdb+0x62d864) bminor#9 language_defn::parser(parser_state*) const gdb/language.c:598 (gdb+0x9771c5) bminor#10 parse_exp_in_context gdb/parse.c:414 (gdb+0xb10a9b) bminor#11 parse_expression(char const*, innermost_block_tracker*, enum_flags<parser_flag>) gdb/parse.c:462 (gdb+0xb110ae) bminor#12 process_print_command_args gdb/printcmd.c:1321 (gdb+0xb4bf0c) #13 print_command_1 gdb/printcmd.c:1335 (gdb+0xb4ca2a) #14 print_command gdb/printcmd.c:1468 (gdb+0xb4cd5a) #15 do_simple_func gdb/cli/cli-decode.c:95 (gdb+0x65b078) #16 cmd_func(cmd_list_element*, char const*, int) gdb/cli/cli-decode.c:2735 (gdb+0x65ed53) #17 execute_command(char const*, int) gdb/top.c:575 (gdb+0xe3a76a) #18 catch_command_errors gdb/main.c:518 (gdb+0xa1837d) #19 execute_cmdargs gdb/main.c:617 (gdb+0xa1853f) #20 captured_main_1 gdb/main.c:1289 (gdb+0xa1aa58) #21 captured_main gdb/main.c:1310 (gdb+0xa1b95a) #22 gdb_main(captured_main_args*) gdb/main.c:1339 (gdb+0xa1b95a) #23 main gdb/gdb.c:39 (gdb+0x42506a) Previous read of size 1 at 0x7b200000410d by thread T1: #0 write_gdbindex gdb/dwarf2/index-write.c:1214 (gdb+0x75bb30) #1 write_dwarf_index(dwarf2_per_bfd*, char const*, char const*, char const*, dw_index_kind) gdb/dwarf2/index-write.c:1469 (gdb+0x75f803) #2 index_cache::store(dwarf2_per_bfd*, index_cache_store_context const&) gdb/dwarf2/index-cache.c:173 (gdb+0x755a36) bminor#3 cooked_index::maybe_write_index(dwarf2_per_bfd*, index_cache_store_context const&) gdb/dwarf2/cooked-index.c:642 (gdb+0x71c96d) bminor#4 operator() gdb/dwarf2/cooked-index.c:471 (gdb+0x71c96d) bminor#5 _M_invoke /usr/include/c++/7/bits/std_function.h:316 (gdb+0x71c96d) bminor#6 std::function<void ()>::operator()() const /usr/include/c++/7/bits/std_function.h:706 (gdb+0x72a57c) bminor#7 void std::__invoke_impl<void, std::function<void ()>&>(std::__invoke_other, std::function<void ()>&) /usr/include/c++/7/bits/invoke.h:60 (gdb+0x72a5db) bminor#8 std::__invoke_result<std::function<void ()>&>::type std::__invoke<std::function<void ()>&>(std::function<void ()>&) /usr/include/c++/7/bits/invoke.h:95 (gdb+0x72a5db) bminor#9 std::__future_base::_Task_state<std::function<void ()>, std::allocator<int>, void ()>::_M_run()::{lambda()#1}::operator()() const /usr/include/c++/7/future:1421 (gdb+0x72a5db) bminor#10 std::__future_base::_Task_setter<std::unique_ptr<std::__future_base::_Result<void>, std::__future_base::_Result_base::_Deleter>, std::__future_base::_Task_state<std::function<void ()>, std::allocator<int>, void ()>::_M_run()::{lambda()#1}, void>::operator()() const /usr/include/c++/7/future:1362 (gdb+0x72a5db) bminor#11 std::_Function_handler<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> (), std::__future_base::_Task_setter<std::unique_ptr<std::__future_base::_Result<void>, std::__future_base::_Result_base::_Deleter>, std::__future_base::_Task_state<std::function<void ()>, std::allocator<int>, void ()>::_M_run()::{lambda()#1}, void> >::_M_invoke(std::_Any_data const&) /usr/include/c++/7/bits/std_function.h:302 (gdb+0x72a5db) bminor#12 std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>::operator()() const /usr/include/c++/7/bits/std_function.h:706 (gdb+0x724954) #13 std::__future_base::_State_baseV2::_M_do_set(std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*) /usr/include/c++/7/future:561 (gdb+0x724954) #14 void std::__invoke_impl<void, void (std::__future_base::_State_baseV2::*)(std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*), std::__future_base::_State_baseV2*, std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*>(std::__invoke_memfun_deref, void (std::__future_base::_State_baseV2::*&&)(std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*), std::__future_base::_State_baseV2*&&, std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*&&, bool*&&) /usr/include/c++/7/bits/invoke.h:73 (gdb+0x72434a) #15 std::__invoke_result<void (std::__future_base::_State_baseV2::*)(std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*), std::__future_base::_State_baseV2*, std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*>::type std::__invoke<void (std::__future_base::_State_baseV2::*)(std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*), std::__future_base::_State_baseV2*, std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*>(void (std::__future_base::_State_baseV2::*&&)(std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*), std::__future_base::_State_baseV2*&&, std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*&&, bool*&&) /usr/include/c++/7/bits/invoke.h:95 (gdb+0x72434a) #16 std::call_once<void (std::__future_base::_State_baseV2::*)(std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*), std::__future_base::_State_baseV2*, std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*>(std::once_flag&, void (std::__future_base::_State_baseV2::*&&)(std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*), std::__future_base::_State_baseV2*&&, std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*&&, bool*&&)::{lambda()#1}::operator()() const /usr/include/c++/7/mutex:672 (gdb+0x72434a) #17 std::call_once<void (std::__future_base::_State_baseV2::*)(std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*), std::__future_base::_State_baseV2*, std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*>(std::once_flag&, void (std::__future_base::_State_baseV2::*&&)(std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*), std::__future_base::_State_baseV2*&&, std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*&&, bool*&&)::{lambda()#2}::operator()() const /usr/include/c++/7/mutex:677 (gdb+0x72434a) #18 std::call_once<void (std::__future_base::_State_baseV2::*)(std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*), std::__future_base::_State_baseV2*, std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*>(std::once_flag&, void (std::__future_base::_State_baseV2::*&&)(std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*), std::__future_base::_State_baseV2*&&, std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*&&, bool*&&)::{lambda()#2}::_FUN() /usr/include/c++/7/mutex:677 (gdb+0x72434a) #19 pthread_once <null> (libtsan.so.0+0x4457c) #20 __gthread_once /usr/include/c++/7/x86_64-suse-linux/bits/gthr-default.h:699 (gdb+0x72532b) #21 void std::call_once<void (std::__future_base::_State_baseV2::*)(std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*), std::__future_base::_State_baseV2*, std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*>(std::once_flag&, void (std::__future_base::_State_baseV2::*&&)(std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*), std::__future_base::_State_baseV2*&&, std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*&&, bool*&&) /usr/include/c++/7/mutex:684 (gdb+0x72532b) #22 std::__future_base::_State_baseV2::_M_set_result(std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>, bool) /usr/include/c++/7/future:401 (gdb+0x174568d) #23 std::__future_base::_Task_state<std::function<void ()>, std::allocator<int>, void ()>::_M_run() /usr/include/c++/7/future:1423 (gdb+0x174568d) #24 std::packaged_task<void ()>::operator()() /usr/include/c++/7/future:1556 (gdb+0x174568d) #25 gdb::thread_pool::thread_function() gdbsupport/thread-pool.cc:242 (gdb+0x174568d) #26 void std::__invoke_impl<void, void (gdb::thread_pool::*)(), gdb::thread_pool*>(std::__invoke_memfun_deref, void (gdb::thread_pool::*&&)(), gdb::thread_pool*&&) /usr/include/c++/7/bits/invoke.h:73 (gdb+0x1748040) #27 std::__invoke_result<void (gdb::thread_pool::*)(), gdb::thread_pool*>::type std::__invoke<void (gdb::thread_pool::*)(), gdb::thread_pool*>(void (gdb::thread_pool::*&&)(), gdb::thread_pool*&&) /usr/include/c++/7/bits/invoke.h:95 (gdb+0x1748040) #28 decltype (__invoke((_S_declval<0ul>)(), (_S_declval<1ul>)())) std::thread::_Invoker<std::tuple<void (gdb::thread_pool::*)(), gdb::thread_pool*> >::_M_invoke<0ul, 1ul>(std::_Index_tuple<0ul, 1ul>) /usr/include/c++/7/thread:234 (gdb+0x1748040) #29 std::thread::_Invoker<std::tuple<void (gdb::thread_pool::*)(), gdb::thread_pool*> >::operator()() /usr/include/c++/7/thread:243 (gdb+0x1748040) #30 std::thread::_State_impl<std::thread::_Invoker<std::tuple<void (gdb::thread_pool::*)(), gdb::thread_pool*> > >::_M_run() /usr/include/c++/7/thread:186 (gdb+0x1748040) #31 <null> <null> (libstdc++.so.6+0xdcac2) ... SUMMARY: ThreadSanitizer: data race gdb/dwarf2/read.c:3077 in dw_expand_symtabs_matching_file_matcher(dwarf2_per_objfile*, gdb::function_view<bool (char const*, bool)>) ... The race happens when issuing the "file $exec" command. The race is between: - a worker thread writing the index cache, and in the process reading dwarf2_per_cu_data::is_debug_type, and - the main thread writing to dwarf2_per_cu_data::mark. The two bitfields dwarf2_per_cu_data::mark and dwarf2_per_cu_data::is_debug_type share the same bitfield container. Fix this by making dwarf2_per_cu_data::mark a packed<unsigned int, 1>. Tested on x86_64-linux. PR symtab/30718 Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=30718

…g_types} With gdb build with -fsanitize=thread, and the exec from test-case gdb.base/index-cache.exp, I run into: ... $ rm -f ~/.cache/gdb/*; \ gdb -q -batch -iex "set index-cache enabled on" index-cache \ -ex "print foobar" ... WARNING: ThreadSanitizer: data race (pid=25018) Write of size 1 at 0x7b200000410d by main thread: #0 dw2_get_file_names_reader gdb/dwarf2/read.c:2033 (gdb+0x7ab023) #1 dw2_get_file_names gdb/dwarf2/read.c:2130 (gdb+0x7ab023) #2 dw_expand_symtabs_matching_file_matcher(dwarf2_per_objfile*, gdb::function_view<bool (char const*, bool)>) gdb/dwarf2/read.c:3105 (gdb+0x7ac6e9) bminor#3 cooked_index_functions::expand_symtabs_matching(objfile*, gdb::function_view<bool (char const*, bool)>, lookup_name_info const*, gdb::function_view<bool (char const*)>, gdb::function_view<bool (compunit_symtab*)>, enum_flags<block_search_flag_values>, domain_enum, search_domain) gdb/dwarf2/read.c:16812 (gdb+0x7d040f) bminor#4 objfile::map_symtabs_matching_filename(char const*, char const*, gdb::function_view<bool (symtab*)>) gdb/symfile-debug.c:219 (gdb+0xda5b6e) bminor#5 iterate_over_symtabs(char const*, gdb::function_view<bool (symtab*)>) gdb/symtab.c:648 (gdb+0xdc441d) bminor#6 lookup_symtab(char const*) gdb/symtab.c:662 (gdb+0xdc4522) bminor#7 classify_name gdb/c-exp.y:3083 (gdb+0x61afec) bminor#8 c_yylex gdb/c-exp.y:3251 (gdb+0x61dd13) bminor#9 c_yyparse() build/gdb/c-exp.c.tmp:1988 (gdb+0x61f07e) bminor#10 c_parse(parser_state*) gdb/c-exp.y:3417 (gdb+0x62d864) bminor#11 language_defn::parser(parser_state*) const gdb/language.c:598 (gdb+0x977245) bminor#12 parse_exp_in_context gdb/parse.c:414 (gdb+0xb10b1b) #13 parse_expression(char const*, innermost_block_tracker*, enum_flags<parser_flag>) gdb/parse.c:462 (gdb+0xb1112e) #14 process_print_command_args gdb/printcmd.c:1321 (gdb+0xb4bf8c) #15 print_command_1 gdb/printcmd.c:1335 (gdb+0xb4caaa) #16 print_command gdb/printcmd.c:1468 (gdb+0xb4cdda) #17 do_simple_func gdb/cli/cli-decode.c:95 (gdb+0x65b078) #18 cmd_func(cmd_list_element*, char const*, int) gdb/cli/cli-decode.c:2735 (gdb+0x65ed53) #19 execute_command(char const*, int) gdb/top.c:575 (gdb+0xe3a7ea) #20 catch_command_errors gdb/main.c:518 (gdb+0xa183fd) #21 execute_cmdargs gdb/main.c:617 (gdb+0xa185bf) #22 captured_main_1 gdb/main.c:1289 (gdb+0xa1aad8) #23 captured_main gdb/main.c:1310 (gdb+0xa1b9da) #24 gdb_main(captured_main_args*) gdb/main.c:1339 (gdb+0xa1b9da) #25 main gdb/gdb.c:39 (gdb+0x42506a) Previous read of size 1 at 0x7b200000410d by thread T2: #0 write_gdbindex gdb/dwarf2/index-write.c:1214 (gdb+0x75bb30) #1 write_dwarf_index(dwarf2_per_bfd*, char const*, char const*, char const*, dw_index_kind) gdb/dwarf2/index-write.c:1469 (gdb+0x75f803) #2 index_cache::store(dwarf2_per_bfd*, index_cache_store_context const&) gdb/dwarf2/index-cache.c:173 (gdb+0x755a36) bminor#3 cooked_index::maybe_write_index(dwarf2_per_bfd*, index_cache_store_context const&) gdb/dwarf2/cooked-index.c:642 (gdb+0x71c96d) bminor#4 operator() gdb/dwarf2/cooked-index.c:471 (gdb+0x71c96d) bminor#5 _M_invoke /usr/include/c++/7/bits/std_function.h:316 (gdb+0x71c96d) bminor#6 std::function<void ()>::operator()() const /usr/include/c++/7/bits/std_function.h:706 (gdb+0x72a57c) bminor#7 void std::__invoke_impl<void, std::function<void ()>&>(std::__invoke_other, std::function<void ()>&) /usr/include/c++/7/bits/invoke.h:60 (gdb+0x72a5db) bminor#8 std::__invoke_result<std::function<void ()>&>::type std::__invoke<std::function<void ()>&>(std::function<void ()>&) /usr/include/c++/7/bits/invoke.h:95 (gdb+0x72a5db) bminor#9 std::__future_base::_Task_state<std::function<void ()>, std::allocator<int>, void ()>::_M_run()::{lambda()#1}::operator()() const /usr/include/c++/7/future:1421 (gdb+0x72a5db) bminor#10 std::__future_base::_Task_setter<std::unique_ptr<std::__future_base::_Result<void>, std::__future_base::_Result_base::_Deleter>, std::__future_base::_Task_state<std::function<void ()>, std::allocator<int>, void ()>::_M_run()::{lambda()#1}, void>::operator()() const /usr/include/c++/7/future:1362 (gdb+0x72a5db) bminor#11 std::_Function_handler<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> (), std::__future_base::_Task_setter<std::unique_ptr<std::__future_base::_Result<void>, std::__future_base::_Result_base::_Deleter>, std::__future_base::_Task_state<std::function<void ()>, std::allocator<int>, void ()>::_M_run()::{lambda()#1}, void> >::_M_invoke(std::_Any_data const&) /usr/include/c++/7/bits/std_function.h:302 (gdb+0x72a5db) bminor#12 std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>::operator()() const /usr/include/c++/7/bits/std_function.h:706 (gdb+0x724954) #13 std::__future_base::_State_baseV2::_M_do_set(std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*) /usr/include/c++/7/future:561 (gdb+0x724954) #14 void std::__invoke_impl<void, void (std::__future_base::_State_baseV2::*)(std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*), std::__future_base::_State_baseV2*, std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*>(std::__invoke_memfun_deref, void (std::__future_base::_State_baseV2::*&&)(std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*), std::__future_base::_State_baseV2*&&, std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*&&, bool*&&) /usr/include/c++/7/bits/invoke.h:73 (gdb+0x72434a) #15 std::__invoke_result<void (std::__future_base::_State_baseV2::*)(std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*), std::__future_base::_State_baseV2*, std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*>::type std::__invoke<void (std::__future_base::_State_baseV2::*)(std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*), std::__future_base::_State_baseV2*, std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*>(void (std::__future_base::_State_baseV2::*&&)(std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*), std::__future_base::_State_baseV2*&&, std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*&&, bool*&&) /usr/include/c++/7/bits/invoke.h:95 (gdb+0x72434a) #16 std::call_once<void (std::__future_base::_State_baseV2::*)(std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*), std::__future_base::_State_baseV2*, std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*>(std::once_flag&, void (std::__future_base::_State_baseV2::*&&)(std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*), std::__future_base::_State_baseV2*&&, std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*&&, bool*&&)::{lambda()#1}::operator()() const /usr/include/c++/7/mutex:672 (gdb+0x72434a) #17 std::call_once<void (std::__future_base::_State_baseV2::*)(std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*), std::__future_base::_State_baseV2*, std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*>(std::once_flag&, void (std::__future_base::_State_baseV2::*&&)(std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*), std::__future_base::_State_baseV2*&&, std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*&&, bool*&&)::{lambda()#2}::operator()() const /usr/include/c++/7/mutex:677 (gdb+0x72434a) #18 std::call_once<void (std::__future_base::_State_baseV2::*)(std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*), std::__future_base::_State_baseV2*, std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*>(std::once_flag&, void (std::__future_base::_State_baseV2::*&&)(std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*), std::__future_base::_State_baseV2*&&, std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*&&, bool*&&)::{lambda()#2}::_FUN() /usr/include/c++/7/mutex:677 (gdb+0x72434a) #19 pthread_once <null> (libtsan.so.0+0x4457c) #20 __gthread_once /usr/include/c++/7/x86_64-suse-linux/bits/gthr-default.h:699 (gdb+0x72532b) #21 void std::call_once<void (std::__future_base::_State_baseV2::*)(std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*), std::__future_base::_State_baseV2*, std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*>(std::once_flag&, void (std::__future_base::_State_baseV2::*&&)(std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*), std::__future_base::_State_baseV2*&&, std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*&&, bool*&&) /usr/include/c++/7/mutex:684 (gdb+0x72532b) #22 std::__future_base::_State_baseV2::_M_set_result(std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>, bool) /usr/include/c++/7/future:401 (gdb+0x174570d) #23 std::__future_base::_Task_state<std::function<void ()>, std::allocator<int>, void ()>::_M_run() /usr/include/c++/7/future:1423 (gdb+0x174570d) #24 std::packaged_task<void ()>::operator()() /usr/include/c++/7/future:1556 (gdb+0x174570d) #25 gdb::thread_pool::thread_function() gdbsupport/thread-pool.cc:242 (gdb+0x174570d) #26 void std::__invoke_impl<void, void (gdb::thread_pool::*)(), gdb::thread_pool*>(std::__invoke_memfun_deref, void (gdb::thread_pool::*&&)(), gdb::thread_pool*&&) /usr/include/c++/7/bits/invoke.h:73 (gdb+0x17480c0) #27 std::__invoke_result<void (gdb::thread_pool::*)(), gdb::thread_pool*>::type std::__invoke<void (gdb::thread_pool::*)(), gdb::thread_pool*>(void (gdb::thread_pool::*&&)(), gdb::thread_pool*&&) /usr/include/c++/7/bits/invoke.h:95 (gdb+0x17480c0) #28 decltype (__invoke((_S_declval<0ul>)(), (_S_declval<1ul>)())) std::thread::_Invoker<std::tuple<void (gdb::thread_pool::*)(), gdb::thread_pool*> >::_M_invoke<0ul, 1ul>(std::_Index_tuple<0ul, 1ul>) /usr/include/c++/7/thread:234 (gdb+0x17480c0) #29 std::thread::_Invoker<std::tuple<void (gdb::thread_pool::*)(), gdb::thread_pool*> >::operator()() /usr/include/c++/7/thread:243 (gdb+0x17480c0) #30 std::thread::_State_impl<std::thread::_Invoker<std::tuple<void (gdb::thread_pool::*)(), gdb::thread_pool*> > >::_M_run() /usr/include/c++/7/thread:186 (gdb+0x17480c0) #31 <null> <null> (libstdc++.so.6+0xdcac2) ... SUMMARY: ThreadSanitizer: data race gdb/dwarf2/read.c:2033 in dw2_get_file_names_reader ... The race happens when issuing the "file $exec" command. The race is between: - a worker thread writing the index cache, and in the process reading dwarf2_per_cu_data::is_debug_type, and - the main thread writing to dwarf2_per_cu_data::files_read. The two bitfields dwarf2_per_cu_data::files_read and dwarf2_per_cu_data::is_debug_type share the same bitfield container. Fix this by making dwarf2_per_cu_data::files_read a packed<bool, 1>. Tested on x86_64-linux. PR symtab/30718 Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=30718

It was pointed out on the mailing list[1] that after this commit: commit b1e0126 Date: Wed Jun 21 14:18:54 2023 +0100 gdb: don't resume vfork parent while child is still running the test gdb.base/vfork-follow-parent.exp now has some failures when run with the native-gdbserver or native-extended-gdbserver boards: FAIL: gdb.base/vfork-follow-parent.exp: resolution_method=schedule-multiple: continue to end of inferior 2 (timeout) FAIL: gdb.base/vfork-follow-parent.exp: resolution_method=schedule-multiple: inferior 1 (timeout) FAIL: gdb.base/vfork-follow-parent.exp: resolution_method=schedule-multiple: print unblock_parent = 1 (timeout) FAIL: gdb.base/vfork-follow-parent.exp: resolution_method=schedule-multiple: continue to break_parent (timeout) The reason that these failures don't show up when run on the standard unix board is that the test is only run in the default operating mode, so for Linux this will be all-stop on top of non-stop. If we adjust the test script so that it runs in the default mode and with target-non-stop turned off, then we see the same failures on the unix board. This commit includes this change. The way that the test is written means that it is not (currently) possible to turn on non-stop mode and have the test still work, so this commit does not do that. I have also updated the test script so that the vfork child performs an exec as well as the current exit. Exec and exit are the two ways in which a vfork child can release the vfork parent, so testing both of these cases is useful I think. In this test the inferior performs a vfork and the vfork-child immediately exits. The vfork-parent will wait for the vfork-child and then blocks waiting for gdb. Once gdb has released the vfork-parent, the vfork-parent also exits. In the test that fails, GDB sets 'detach-on-fork off' and then runs to the vfork. At this point the test tries to just "continue", but this fails as the vfork-parent is still selected, and the parent can't continue until the vfork-child completes. As the vfork-child is stopped by GDB the parent will never stop once resumed, so GDB refuses to resume it. The test script then sets 'schedule-multiple on' and once again continues. This time GDB, in theory, resumes both the parent and the child, the parent will be held blocked by the kernel, but the child will run until it exits, and which point GDB stops again, this time with inferior 2, the newly exited vfork-child, selected. What happens after this in the test script is irrelevant as far as this failure is concerned. To understand why the test started failing we should consider the behaviour of four different cases: 1. All-stop-on-non-stop before commit b1e0126, 2. All-stop-on-non-stop after commit b1e0126, 3. All-stop-on-all-stop before commit b1e0126, and 4. All-stop-on-all-stop after commit b1e0126. Only case bminor#4 is failing after commit b1e0126, but I think the other cases are interesting because, (a) they inform how we might fix the regression, and (b) it turns out the behaviour of #2 changed too with the commit, but the change was harmless. For #1 All-stop-on-non-stop before commit b1e0126, what happens is: 1. GDB calls proceed with the vfork-parent selected, as schedule multiple is on user_visible_resume_ptid returns -1 (everything) as the resume_ptid (see proceed function), 2. As this is all-stop-on-non-stop, every thread is resumed individually, so GDB tries to resume both the vfork-parent and the vfork-child, both of which succeed, 3. The vfork-parent is held stopped by the kernel, 4. The vfork-child completes (exits) at which point the GDB sees the EXITED event for the vfork-child and the VFORK_DONE event for the vfork-parent, 5. At this point we might take two paths depending on which event GDB handles first, if GDB handles the VFORK_DONE first then: (a) As GDB is controlling both parent and child the VFORK_DONE is ignored (see handle_vfork_done), the vfork-parent will be resumed, (b) GDB processes the EXITED event, selects the (now defunct) vfork-child, and stops, returning control to the user. Alternatively, if GDB selects the EXITED event first then: (c) GDB processes the EXITED event, selects the (now defunct) vfork-child, and stops, returning control to the user. (d) At some future time the user resumes the vfork-parent, at which point the VFORK_DONE is reported to GDB, however, GDB is ignoring the VFORK_DONE (see handle_vfork_done), so the parent is resumed. For case #2, all-stop-on-non-stop after commit b1e0126, the important difference is in step (2) above, now, instead of resuming both the vfork-parent and the vfork-child, only the vfork-child is resumed. As such, when we get to step (5), only a single event, the EXITED event is reported. GDB handles the EXITED just as in (5)(c), then, later, when the user resumes the vfork-parent, the VFORKED_DONE is immediately delivered from the kernel, but this is ignored just as in (5)(d), and so, though the pattern of when the vfork-parent is resumed changes, the overall pattern of which events are reported and when, doesn't actually change. In fact, by not resuming the vfork-parent, the order of events (in this test) is now deterministic, which (maybe?) is a good thing. If we now consider case bminor#3, all-stop-on-all-stop before commit b1e0126, then what happens is: 1. GDB calls proceed with the vfork-parent selected, as schedule multiple is on user_visible_resume_ptid returns -1 (everything) as the resume_ptid (see proceed function), 2. As this is all-stop-on-all-stop, the resume is passed down to the linux-nat target, the vfork-parent is the event thread, while the vfork-child is a sibling of the event thread, 3. In linux_nat_target::resume, GDB calls linux_nat_resume_callback for all threads, this causes the vfork-child to be resumed. Then in linux_nat_target::resume, the event thread, the vfork-parent, is also resumed. 4. The vfork-parent is held stopped by the kernel, 5. The vfork-child completes (exits) at which point the GDB sees the EXITED event for the vfork-child and the VFORK_DONE event for the vfork-parent, 6. We are now in a situation identical to step (5) as for all-stop-on-non-stop above, GDB selects one of the events to handle, and whichever we select the user sees the correct behaviour. And so, finally, we can consider bminor#4, all-stop-on-all-stop after commit b1e0126, this is the case that started failing. We start out just like above, in proceed, the resume_ptid is -1 (resume everything), due to schedule multiple being on. And just like above, due to the target being all-stop, we call proceed_resume_thread_checked just once, for the current thread, which, remember, is the vfork-parent thread. The change in commit b1e0126 was to avoid resuming a vfork-parent thread, read the commit message for the justification for this change. However, this means that GDB now rejects resuming the vfork-parent in this case, which means that nothing gets resumed! Obviously, if nothing resumes, then nothing will ever stop, and so GDB appears to hang. I considered a couple of solutions which, in the end, I didn't go with, these were: 1. Move the vfork-parent check out of proceed_resume_thread_checked, and place it in proceed, but only on the all-stop-on-non-stop path, this should still address the issue seen in b1e0126, but would avoid the issue seen here. I rejected this just because it didn't feel great to split the checks that exist in proceed_resume_thread_checked like this, 2. Extend the condition in proceed_resume_thread_checked by adding a target_is_non_stop_p check. This would have the same effect as idea 1, but leaves all the checks in the same place, which I think would be better, but this still just didn't feel right to me, and so, What I noticed was that for the all-stop-on-non-stop, after commit b1e0126, we only resumed the vfork-child, and this seems fine. The vfork-parent isn't going to run anyway (the kernel will hold it back), so if feels like we there's no harm in just waiting for the child to complete, and then resuming the parent. So then I started looking at follow_fork, which is called from the top of proceed. This function already has the task of switching between the parent and child based on which the user wishes to follow. So, I wondered, could we use this to switch to the vfork-child in the case that we are attached to both? Turns out this is pretty simple to do. Having done that, now the process is for all-stop-on-all-stop after commit b1e0126, and with this new fix is: 1. GDB calls proceed with the vfork-parent selected, but, 2. In follow_fork, and follow_fork_inferior, GDB switches the selected thread to be that of the vfork-child, 3. Back in proceed user_visible_resume_ptid returns -1 (everything) as the resume_ptid still, but now, 4. When GDB calls proceed_resume_thread_checked, the vfork-child is the current selected thread, this is not a vfork-parent, and so GDB allows the proceed to continue to the linux-nat target, 5. In linux_nat_target::resume, GDB calls linux_nat_resume_callback for all threads, this does not resume the vfork-parent (because it is a vfork-parent), and then the vfork-child is resumed as this is the event thread, At this point we are back in the same situation as for all-stop-on-non-stop after commit b1e0126, that is, the vfork-child is resumed, while the vfork-parent is held stopped by GDB. Eventually the vfork-child will exit or exec, at which point the vfork-parent will be resumed. [1] https://inbox.sourceware.org/gdb-patches/3e1e1db0-13d9-dd32-b4bb-051149ae6e76@simark.ca/

After running a number of programs under Windows gdb and detaching them, I typed run in gdb, and got a hang, here: (top-gdb) bt #0 sharing_input_terminal (pid=4672) at /home/pedro/gdb/src/gdb/mingw-hdep.c:388 #1 0x00007ff71a2d8678 in sharing_input_terminal (inf=0x23bf23dafb0) at /home/pedro/gdb/src/gdb/inflow.c:269 #2 0x00007ff71a2d887b in child_terminal_save_inferior (self=0x23bf23de060) at /home/pedro/gdb/src/gdb/inflow.c:423 bminor#3 0x00007ff71a2c80c0 in inf_child_target::terminal_save_inferior (this=0x23bf23de060) at /home/pedro/gdb/src/gdb/inf-child.c:111 bminor#4 0x00007ff71a429c0f in target_terminal_is_ours_kind (desired_state=target_terminal_state::is_ours_for_output) at /home/pedro/gdb/src/gdb/target.c:1037 bminor#5 0x00007ff71a429e02 in target_terminal::ours_for_output () at /home/pedro/gdb/src/gdb/target.c:1094 bminor#6 0x00007ff71a2ccc8e in post_create_inferior (from_tty=0) at /home/pedro/gdb/src/gdb/infcmd.c:245 bminor#7 0x00007ff71a2cd431 in run_command_1 (args=0x0, from_tty=0, run_how=RUN_NORMAL) at /home/pedro/gdb/src/gdb/infcmd.c:502 bminor#8 0x00007ff71a2cd58b in run_command (args=0x0, from_tty=0) at /home/pedro/gdb/src/gdb/infcmd.c:527 The problem is that the loop around GetConsoleProcessList looped forever, because there were exactly 10 processes to return. GetConsoleProcessList's documentation says: If the buffer is too small to hold all the valid process identifiers, the return value is the required number of array elements. The function will have stored no identifiers in the buffer. In this situation, use the return value to allocate a buffer that is large enough to store the entire list and call the function again. In this case, the buffer wasn't too small, it was exactly the right size, so we should have broken out of the loop. We didn't due to a "<" check that should have been "<=". That is fixed by this patch. Approved-By: Tom Tromey <tom@tromey.com> Reviewed-By: Eli Zaretskii <eliz@gnu.org> Change-Id: I14e4909f2ac2fa83d0d9b6e64418b5831ac4e4e3

When running test-case gdb.base/add-symbol-file-attach.exp with target board unix/-m32, we run into: ... (gdb) attach 3955^M Attaching to process 3955^M Load new symbol table from "add-symbol-file-attach"? (y or n) y^M Reading symbols from add-symbol-file-attach/add-symbol-file-attach...^M Reading symbols from /lib/libm.so.6...^M Reading symbols from /usr/lib/debug/lib/libm-2.31.so-i386.debug...^M Reading symbols from /lib/libc.so.6...^M Reading symbols from /usr/lib/debug/lib/libc-2.31.so-i386.debug...^M Reading symbols from /lib/ld-linux.so.2...^M Reading symbols from /usr/lib/debug/lib/ld-2.31.so-i386.debug...^M 0xf7f53549 in __kernel_vsyscall ()^M (gdb) FAIL: gdb.base/add-symbol-file-attach.exp: attach ... The test fails because this regexp is used: ... -re ".*in \[_A-Za-z0-9\]*pause.*$gdb_prompt $" { ... The regexp attempts to detect that the exec is somewhere in pause (): ... int main (int argc, char **argv) { pause (); return 0; } ... but when the exec is blocked in pause, the backtrace is: ... (gdb) bt #0 0xf7fd2549 in __kernel_vsyscall () #1 0xf7d84966 in __libc_pause () at ../sysdeps/unix/sysv/linux/pause.c:29 #2 0x0804844c in main (argc=1, argv=0xffffce84) at /data/vries/gdb/src/gdb/testsuite/gdb.base/add-symbol-file-attach.c:26 ... We could simply extend the regexp to also match __kernel_vsyscall, but the more fundamental problem is that the test is racy. The attach can happen before the exec is blocked in pause (), somewhere in the dynamic linker resolving the call to pause, in main or even earlier. Note that for the test-case to be effective, the exec is not required to be in pause (). I added a "while (1);" loop at the start of main, reverted the patch fixing the corresponding PR and reproduced the problem it's supposed to detect. Fix this by simply matching the "Reading symbols from" line, similar to what an earlier test is doing. While we're at it, rewrite the earlier test to also use the -wrap idiom. Tested on x86_64-linux.

On aarch64-linux, with gcc 13.2.1, I run into: ... (gdb) backtrace^M #0 break_here () at solib-search.c:30^M #1 0x0000fffff7f20194 in lib2_func4 () at solib-search-lib2.c:50^M #2 0x0000fffff7f70194 in lib1_func3 () at solib-search-lib1.c:50^M bminor#3 0x0000fffff7f20174 in lib2_func2 () at solib-search-lib2.c:30^M bminor#4 0x0000fffff7f70174 in lib1_func1 () at solib-search-lib1.c:30^M bminor#5 0x00000000004101b4 in main () at solib-search.c:23^M (gdb) PASS: gdb.base/solib-search.exp: \ backtrace (with wrong libs) (data collection) FAIL: gdb.base/solib-search.exp: backtrace (with wrong libs) ... The FAIL is generated by this code in the test-case: ... if { $expect_fail } { # If the backtrace output is correct the test isn't sufficiently # testing what it should. if { $count == $total_expected } { set fail 1 } ... The test-case: - builds two versions of two shared libs, a "right" and "wrong" version, the difference being an additional dummy function (called spacer function), - uses the "right" version to generate a core file, - uses the "wrong" version to interpret the core file, and - generates a backtrace. The intent is that the backtrace is incorrect due to using the "wrong" version, but actually it's correct. This is because the spacer functions aren't large enough. Fix this by increasing the size of the spacer functions by adding a dummy loop, after which we have, as expected, an incorrect backtrace: ... (gdb) backtrace^M #0 break_here () at solib-search.c:30^M #1 0x0000fffff7f201c0 in ?? ()^M #2 0x0000fffff7f20174 in lib2_func2 () at solib-search-lib2.c:30^M bminor#3 0x0000fffff7f20174 in lib2_func2 () at solib-search-lib2.c:30^M bminor#4 0x0000fffff7f70174 in lib1_func1 () at solib-search-lib1.c:30^M bminor#5 0x00000000004101b4 in main () at solib-search.c:23^M (gdb) PASS: gdb.base/solib-search.exp: \ backtrace (with wrong libs) (data collection) PASS: gdb.base/solib-search.exp: backtrace (with wrong libs) ... Tested on aarch64-linux.

The testsuite for SCFI contains target-specific tests. When a test is executed with --scfi=experimental command line option, the CFI annotations in the test .s files are skipped altogether by the GAS for processing. The CFI directives in the input assembly files are, however, validated by running the assembler one more time without --scfi=experimental. Some testcases are used to highlight those asm constructs that the SCFI machinery in GAS currently does not support: - Only System V AMD64 ABI is supported for now. Using either --32 or --x32 with SCFI results in hard error. See scfi-unsupported-1.s. - Untraceable stack-pointer manipulation in function epilougue and prologue. See scfi-unsupported-2.s. - Using Dynamically Realigned Arguement Pointer (DRAP) register to realign the stack. For SCFI, the CFA must be only REG_SP or REG_FP based. See scfi-unsupported-drap-1.s Some testcases are used to highlight some diagnostics that the SCFI machinery in GAS currently issues, with an intent to help user correct inadvertent errors in their hand-written asm. An error is issued when GAS finds that input asm is not amenable to correct CFI synthesis. - (#1) "Warning: SCFI: Asymetrical register restore" - (#2) "Error: SCFI: usage of REG_FP as scratch not supported" - (bminor#3) "Error: SCFI: unsupported stack manipulation pattern" In case of (#2) and (bminor#3), SCFI generation is skipped for the respective function. Above is a subset of the warnings/errors implemented in the code. gas/testsuite/: * gas/scfi/README: New test. * gas/scfi/x86_64/ginsn-add-1.l: New test. * gas/scfi/x86_64/ginsn-add-1.s: New test. * gas/scfi/x86_64/ginsn-dw2-regnum-1.l: New test. * gas/scfi/x86_64/ginsn-dw2-regnum-1.s: New test. * gas/scfi/x86_64/ginsn-pop-1.l: New test. * gas/scfi/x86_64/ginsn-pop-1.s: New test. * gas/scfi/x86_64/ginsn-push-1.l: New test. * gas/scfi/x86_64/ginsn-push-1.s: New test. * gas/scfi/x86_64/scfi-add-1.d: New test. * gas/scfi/x86_64/scfi-add-1.l: New test. * gas/scfi/x86_64/scfi-add-1.s: New test. * gas/scfi/x86_64/scfi-add-2.d: New test. * gas/scfi/x86_64/scfi-add-2.l: New test. * gas/scfi/x86_64/scfi-add-2.s: New test. * gas/scfi/x86_64/scfi-asm-marker-1.d: New test. * gas/scfi/x86_64/scfi-asm-marker-1.l: New test. * gas/scfi/x86_64/scfi-asm-marker-1.s: New test. * gas/scfi/x86_64/scfi-asm-marker-2.d: New test. * gas/scfi/x86_64/scfi-asm-marker-2.l: New test. * gas/scfi/x86_64/scfi-asm-marker-2.s: New test. * gas/scfi/x86_64/scfi-asm-marker-3.d: New test. * gas/scfi/x86_64/scfi-asm-marker-3.l: New test. * gas/scfi/x86_64/scfi-asm-marker-3.s: New test. * gas/scfi/x86_64/scfi-bp-sp-1.d: New test. * gas/scfi/x86_64/scfi-bp-sp-1.l: New test. * gas/scfi/x86_64/scfi-bp-sp-1.s: New test. * gas/scfi/x86_64/scfi-bp-sp-2.d: New test. * gas/scfi/x86_64/scfi-bp-sp-2.l: New test. * gas/scfi/x86_64/scfi-bp-sp-2.s: New test. * gas/scfi/x86_64/scfi-callee-saved-1.d: New test. * gas/scfi/x86_64/scfi-callee-saved-1.l: New test. * gas/scfi/x86_64/scfi-callee-saved-1.s: New test. * gas/scfi/x86_64/scfi-callee-saved-2.d: New test. * gas/scfi/x86_64/scfi-callee-saved-2.l: New test. * gas/scfi/x86_64/scfi-callee-saved-2.s: New test. * gas/scfi/x86_64/scfi-callee-saved-3.d: New test. * gas/scfi/x86_64/scfi-callee-saved-3.l: New test. * gas/scfi/x86_64/scfi-callee-saved-3.s: New test. * gas/scfi/x86_64/scfi-callee-saved-4.d: New test. * gas/scfi/x86_64/scfi-callee-saved-4.l: New test. * gas/scfi/x86_64/scfi-callee-saved-4.s: New test. * gas/scfi/x86_64/scfi-cfg-1.d: New test. * gas/scfi/x86_64/scfi-cfg-1.l: New test. * gas/scfi/x86_64/scfi-cfg-1.s: New test. * gas/scfi/x86_64/scfi-cfg-2.d: New test. * gas/scfi/x86_64/scfi-cfg-2.l: New test. * gas/scfi/x86_64/scfi-cfg-2.s: New test. * gas/scfi/x86_64/scfi-cfi-label-1.d: New test. * gas/scfi/x86_64/scfi-cfi-label-1.l: New test. * gas/scfi/x86_64/scfi-cfi-label-1.s: New test. * gas/scfi/x86_64/scfi-cfi-sections-1.d: New test. * gas/scfi/x86_64/scfi-cfi-sections-1.l: New test. * gas/scfi/x86_64/scfi-cfi-sections-1.s: New test. * gas/scfi/x86_64/scfi-cofi-1.d: New test. * gas/scfi/x86_64/scfi-cofi-1.l: New test. * gas/scfi/x86_64/scfi-cofi-1.s: New test. * gas/scfi/x86_64/scfi-diag-1.l: New test. * gas/scfi/x86_64/scfi-diag-1.s: New test. * gas/scfi/x86_64/scfi-diag-2.l: New test. * gas/scfi/x86_64/scfi-diag-2.s: New test. * gas/scfi/x86_64/scfi-dyn-stack-1.d: New test. * gas/scfi/x86_64/scfi-dyn-stack-1.l: New test. * gas/scfi/x86_64/scfi-dyn-stack-1.s: New test. * gas/scfi/x86_64/scfi-enter-1.d: New test. * gas/scfi/x86_64/scfi-enter-1.l: New test. * gas/scfi/x86_64/scfi-enter-1.s: New test. * gas/scfi/x86_64/scfi-fp-diag-2.l: New test. * gas/scfi/x86_64/scfi-fp-diag-2.s: New test. * gas/scfi/x86_64/scfi-indirect-mov-1.d: New test. * gas/scfi/x86_64/scfi-indirect-mov-1.l: New test. * gas/scfi/x86_64/scfi-indirect-mov-1.s: New test. * gas/scfi/x86_64/scfi-indirect-mov-2.d: New test. * gas/scfi/x86_64/scfi-indirect-mov-2.l: New test. * gas/scfi/x86_64/scfi-indirect-mov-2.s: New test. * gas/scfi/x86_64/scfi-indirect-mov-3.d: New test. * gas/scfi/x86_64/scfi-indirect-mov-3.l: New test. * gas/scfi/x86_64/scfi-indirect-mov-3.s: New test. * gas/scfi/x86_64/scfi-indirect-mov-4.d: New test. * gas/scfi/x86_64/scfi-indirect-mov-4.l: New test. * gas/scfi/x86_64/scfi-indirect-mov-4.s: New test. * gas/scfi/x86_64/scfi-indirect-mov-5.s: New test. * gas/scfi/x86_64/scfi-lea-1.d: New test. * gas/scfi/x86_64/scfi-lea-1.l: New test. * gas/scfi/x86_64/scfi-lea-1.s: New test. * gas/scfi/x86_64/scfi-leave-1.d: New test. * gas/scfi/x86_64/scfi-leave-1.l: New test. * gas/scfi/x86_64/scfi-leave-1.s: New test. * gas/scfi/x86_64/scfi-pushq-1.d: New test. * gas/scfi/x86_64/scfi-pushq-1.l: New test. * gas/scfi/x86_64/scfi-pushq-1.s: New test. * gas/scfi/x86_64/scfi-pushsection-1.d: New test. * gas/scfi/x86_64/scfi-pushsection-1.l: New test. * gas/scfi/x86_64/scfi-pushsection-1.s: New test. * gas/scfi/x86_64/scfi-pushsection-2.d: New test. * gas/scfi/x86_64/scfi-pushsection-2.l: New test. * gas/scfi/x86_64/scfi-pushsection-2.s: New test. * gas/scfi/x86_64/scfi-selfalign-func-1.d: New test. * gas/scfi/x86_64/scfi-selfalign-func-1.l: New test. * gas/scfi/x86_64/scfi-selfalign-func-1.s: New test. * gas/scfi/x86_64/scfi-simple-1.d: New test. * gas/scfi/x86_64/scfi-simple-1.l: New test. * gas/scfi/x86_64/scfi-simple-1.s: New test. * gas/scfi/x86_64/scfi-simple-2.d: New test. * gas/scfi/x86_64/scfi-simple-2.l: New test. * gas/scfi/x86_64/scfi-simple-2.s: New test. * gas/scfi/x86_64/scfi-sub-1.d: New test. * gas/scfi/x86_64/scfi-sub-1.l: New test. * gas/scfi/x86_64/scfi-sub-1.s: New test. * gas/scfi/x86_64/scfi-sub-2.d: New test. * gas/scfi/x86_64/scfi-sub-2.l: New test. * gas/scfi/x86_64/scfi-sub-2.s: New test. * gas/scfi/x86_64/scfi-unsupported-1.l: New test. * gas/scfi/x86_64/scfi-unsupported-1.s: New test. * gas/scfi/x86_64/scfi-unsupported-2.l: New test. * gas/scfi/x86_64/scfi-unsupported-2.s: New test. * gas/scfi/x86_64/scfi-unsupported-3.l: New test. * gas/scfi/x86_64/scfi-unsupported-3.s: New test. * gas/scfi/x86_64/scfi-unsupported-4.l: New test. * gas/scfi/x86_64/scfi-unsupported-4.s: New test. * gas/scfi/x86_64/scfi-unsupported-cfg-1.l: New test. * gas/scfi/x86_64/scfi-unsupported-cfg-1.s: New test. * gas/scfi/x86_64/scfi-unsupported-cfg-2.l: New test. * gas/scfi/x86_64/scfi-unsupported-cfg-2.s: New test. * gas/scfi/x86_64/scfi-unsupported-drap-1.l: New test. * gas/scfi/x86_64/scfi-unsupported-drap-1.s: New test. * gas/scfi/x86_64/scfi-unsupported-insn-1.l: New test. * gas/scfi/x86_64/scfi-unsupported-insn-1.s: New test. * gas/scfi/x86_64/scfi-x86-64.exp: New file.

Similar to the x86_64 testcases, some .s files contain the corresponding CFI directives. This helps in validating the synthesized CFI by running those tests with and without the --scfi=experimental command line option. GAS issues some diagnostics, enabled by default, with --scfi=experimental. The diagnostics have been added with an intent to help user correct inadvertent errors in their hand-written asm. An error is issued when GAS finds that input asm is not amenable to accurate CFI synthesis. The existing scfi-diag-*.s tests in the gas/testsuite/gas/scfi/x86_64 directory test some SCFI diagnostics already: - (#1) "Warning: SCFI: Asymetrical register restore" - (#2) "Error: SCFI: usage of REG_FP as scratch not supported" - (bminor#3) "Error: SCFI: unsupported stack manipulation pattern" - (bminor#4) "Error: untraceable control flow for func 'XXX'" In the newly added aarch64 testsuite, further tests for additional diagnostics have been added: - scfi-diag-1.s in this patch highlights an aarch64-specific diagnostic: (bminor#5) "Warning: SCFI: ignored probable save/restore op with reg offset" Additionally, some testcases are added to showcase the (currently) unsupported patterns, e.g., scfi-unsupported-1.s mov x16, 4384 sub sp, sp, x16 gas/testsuite/: * gas/scfi/README: Update comment to include aarch64. * gas/scfi/aarch64/scfi-aarch64.exp: New file. * gas/scfi/aarch64/ginsn-arith-1.l: New test. * gas/scfi/aarch64/ginsn-arith-1.s: New test. * gas/scfi/aarch64/ginsn-cofi-1.l: New test. * gas/scfi/aarch64/ginsn-cofi-1.s: New test. * gas/scfi/aarch64/ginsn-ldst-1.l: New test. * gas/scfi/aarch64/ginsn-ldst-1.s: New test. * gas/scfi/aarch64/scfi-callee-saved-fp-1.d: New test. * gas/scfi/aarch64/scfi-callee-saved-fp-1.l: New test. * gas/scfi/aarch64/scfi-callee-saved-fp-1.s: New test. * gas/scfi/aarch64/scfi-callee-saved-fp-2.d: New test. * gas/scfi/aarch64/scfi-callee-saved-fp-2.l: New test. * gas/scfi/aarch64/scfi-callee-saved-fp-2.s: New test. * gas/scfi/aarch64/scfi-cb-1.d: New test. * gas/scfi/aarch64/scfi-cb-1.l: New test. * gas/scfi/aarch64/scfi-cb-1.s: New test. * gas/scfi/aarch64/scfi-cfg-1.d: New test. * gas/scfi/aarch64/scfi-cfg-1.l: New test. * gas/scfi/aarch64/scfi-cfg-1.s: New test. * gas/scfi/aarch64/scfi-cfg-2.d: New test. * gas/scfi/aarch64/scfi-cfg-2.l: New test. * gas/scfi/aarch64/scfi-cfg-2.s: New test. * gas/scfi/aarch64/scfi-cfg-3.d: New test. * gas/scfi/aarch64/scfi-cfg-3.l: New test. * gas/scfi/aarch64/scfi-cfg-3.s: New test. * gas/scfi/aarch64/scfi-cfg-4.l: New test. * gas/scfi/aarch64/scfi-cfg-4.s: New test. * gas/scfi/aarch64/scfi-cond-br-1.d: New test. * gas/scfi/aarch64/scfi-cond-br-1.l: New test. * gas/scfi/aarch64/scfi-cond-br-1.s: New test. * gas/scfi/aarch64/scfi-diag-1.l: New test. * gas/scfi/aarch64/scfi-diag-1.s: New test. * gas/scfi/aarch64/scfi-diag-2.l: New test. * gas/scfi/aarch64/scfi-diag-2.s: New test. * gas/scfi/aarch64/scfi-diag-3.l: New test. * gas/scfi/aarch64/scfi-diag-3.s: New test. * gas/scfi/aarch64/scfi-ldrp-1.d: New test. * gas/scfi/aarch64/scfi-ldrp-1.l: New test. * gas/scfi/aarch64/scfi-ldrp-1.s: New test. * gas/scfi/aarch64/scfi-ldrp-2.d: New test. * gas/scfi/aarch64/scfi-ldrp-2.l: New test. * gas/scfi/aarch64/scfi-ldrp-2.s: New test. * gas/scfi/aarch64/scfi-ldstnap-1.d: New test. * gas/scfi/aarch64/scfi-ldstnap-1.l: New test. * gas/scfi/aarch64/scfi-ldstnap-1.s: New test. * gas/scfi/aarch64/scfi-strp-1.d: New test. * gas/scfi/aarch64/scfi-strp-1.l: New test. * gas/scfi/aarch64/scfi-strp-1.s: New test. * gas/scfi/aarch64/scfi-strp-2.d: New test. * gas/scfi/aarch64/scfi-strp-2.l: New test. * gas/scfi/aarch64/scfi-strp-2.s: New test. * gas/scfi/aarch64/scfi-unsupported-1.l: New test. * gas/scfi/aarch64/scfi-unsupported-1.s: New test. * gas/scfi/aarch64/scfi-unsupported-2.l: New test. * gas/scfi/aarch64/scfi-unsupported-2.s: New test.

On arm-linux, I run into: ... PASS: gdb.ada/mi_task_arg.exp: mi runto task_switch.break_me Expecting: ^(-stack-list-arguments 1[^M ]+)?(\^done,stack-args=\[frame={level="0",args=\[\]},frame={level="1",args=\[{name="<_task>",value="0x[0-9A-Fa-f]+"}(,{name="<_taskL>",value="[0-9]+"})?\]},frame={level="2",args=\[({name="self_id",value="(0x[0-9A-Fa-f]+|<optimized out>)"})?\]},.*[^M ]+[(]gdb[)] ^M [ ]*) -stack-list-arguments 1^M ^done,stack-args=[frame={level="0",args=[]},frame={level="1",args=[{name="<_task>",value="0x40bc48"}]},frame={level="2",args=[]}]^M (gdb) ^M FAIL: gdb.ada/mi_task_arg.exp: -stack-list-arguments 1 (unexpected output) ... The problem is that the test-case expects a level 3 frame, but there is none. This can be reproduced using cli bt: ... $ gdb -q -batch outputs/gdb.ada/mi_task_arg/task_switch \ -ex "b task_switch.break_me" \ -ex run \ -ex bt Breakpoint 1 at 0x34b4: file task_switch.adb, line 57. Thread 3 "my_caller" hit Breakpoint 1, task_switch.break_me () \ at task_switch.adb:57 57 null; #0 task_switch.break_me () at task_switch.adb:57 #1 0x00403424 in task_switch.caller (<_task>=0x40bc48) at task_switch.adb:51 #2 0xf7f95a08 in ?? () from /lib/arm-linux-gnueabihf/libgnarl-12.so Backtrace stopped: previous frame identical to this frame (corrupt stack?) ... The purpose of the test-case is printing the frame at level 1, so I don't think we should bother about the presence of the frame at level 3. Fix this by allowing the backtrace to stop at level 2. Tested on arm-linux. Approved-By: Luis Machado <luis.machado@arm.com> Approved-By: Andrew Burgess <aburgess@redhat.com>

Since commit b1da98a ("gdb: remove use of alloca in new_macro_definition"), if cached_argv is empty, we call macro_bcache with a nullptr data. This ends up caught by UBSan deep down in the bcache code: $ ./gdb -nx -q --data-directory=data-directory /home/smarchi/build/binutils-gdb/gdb/testsuite/outputs/gdb.base/macscp/macscp -readnow Reading symbols from /home/smarchi/build/binutils-gdb/gdb/testsuite/outputs/gdb.base/macscp/macscp... Expanding full symbols from /home/smarchi/build/binutils-gdb/gdb/testsuite/outputs/gdb.base/macscp/macscp... /home/smarchi/src/binutils-gdb/gdb/bcache.c:195:12: runtime error: null pointer passed as argument 2, which is declared to never be null The backtrace: #1 0x00007ffff619a05d in __ubsan::__ubsan_handle_nonnull_arg_abort (Data=<optimized out>) at ../../../../src/libsanitizer/ubsan/ubsan_handlers.cpp:750 #2 0x000055556337fba2 in gdb::bcache::insert (this=0x62d0000c8458, addr=0x0, length=0, added=0x0) at /home/smarchi/src/binutils-gdb/gdb/bcache.c:195 bminor#3 0x0000555564b49222 in gdb::bcache::insert<char const*, void> (this=0x62d0000c8458, addr=0x0, length=0, added=0x0) at /home/smarchi/src/binutils-gdb/gdb/bcache.h:158 bminor#4 0x0000555564b481fa in macro_bcache<char const*> (t=0x62100007ae70, addr=0x0, len=0) at /home/smarchi/src/binutils-gdb/gdb/macrotab.c:117 bminor#5 0x0000555564b42b4a in new_macro_definition (t=0x62100007ae70, kind=macro_function_like, special_kind=macro_ordinary, argv=std::__debug::vector of length 0, capacity 0, replacement=0x62a00003af3a "__builtin_va_arg_pack ()") at /home/smarchi/src/binutils-gdb/gdb/macrotab.c:573 bminor#6 0x0000555564b44674 in macro_define_internal (source=0x6210000ab9e0, line=469, name=0x7fffffffa710 "__va_arg_pack", kind=macro_function_like, special_kind=macro_ordinary, argv=std::__debug::vector of length 0, capacity 0, replacement=0x62a00003af3a "__builtin_va_arg_pack ()") at /home/smarchi/src/binutils-gdb/gdb/macrotab.c:777 bminor#7 0x0000555564b44ae2 in macro_define_function (source=0x6210000ab9e0, line=469, name=0x7fffffffa710 "__va_arg_pack", argv=std::__debug::vector of length 0, capacity 0, replacement=0x62a00003af3a "__builtin_va_arg_pack ()") at /home/smarchi/src/binutils-gdb/gdb/macrotab.c:816 bminor#8 0x0000555563f62fc8 in parse_macro_definition (file=0x6210000ab9e0, line=469, body=0x62a00003af2a "__va_arg_pack() __builtin_va_arg_pack ()") at /home/smarchi/src/binutils-gdb/gdb/dwarf2/macro.c:203 This can be reproduced by running gdb.base/macscp.exp. Avoid calling macro_bcache if the macro doesn't have any arguments. Change-Id: I33b5a7c3b3a93d5adba98983fcaae9c8522c383d

Some flavors of indirect call and jmp instructions were not being handled earlier, leading to a GAS error (#1): (#1) "Error: SCFI: unhandled op 0xff may cause incorrect CFI" Not handling jmp/call (direct or indirect) ops is an error (as shown above) because SCFI needs an accurate CFG to synthesize CFI correctly. Recall that the presence of indirect jmp/call, however, does make the CFG ineligible for SCFI. In other words, generating the ginsns for them now, will eventually cause SCFI to bail out later with an error (#2) anyway: (#2) "Error: untraceable control flow for func 'XXX'" The first error (#1) gives the impression of missing functionality in GAS. So, it seems cleaner to synthesize a GINSN_TYPE_JUMP / GINSN_TYPE_CALL now in the backend, and let SCFI machinery complain with the error as expected. The handling for these indirect jmp/call instructions is similar, so reuse the code by carving out a function for the same. Adjust the testcase to include the now handled jmp/call instructions as well. gas/ * config/tc-i386-ginsn.c (x86_ginsn_indirect_branch): New function. (x86_ginsn_new): Refactor out functionality to above. gas/testsuite/ * gas/scfi/x86_64/ginsn-cofi-1.l: Adjust the output. * gas/scfi/x86_64/ginsn-cofi-1.s: Add further varieties of jmp/call opcodes.

A review comment on the SCFI V4 series was to handle ginsn creation for certain lea opcodes more precisely. Specifically, we should preferably handle the following two cases of lea opcodes similarly: - devkitPro#1 lea with "index register and scale factor of 1, but no base register", - devkitPro#2 lea with "no index register, but base register present". Currently, a ginsn of type GINSN_TYPE_OTHER is generated for the case of devkitPro#1 above. For devkitPro#2, however, the lea insn is translated to either a GINSN_TYPE_ADD or GINSN_TYPE_MOV depending on whether the immediate for displacement is non-zero or not respectively. Change the handling in x86_ginsn_lea so that both of the above lea manifestations are handled similarly. While at it, remove the code paths creating GINSN_TYPE_OTHER altogether from the function. It makes sense to piggy back on the x86_ginsn_unhandled code path to create GINSN_TYPE_OTHER if the destination register is interesting. This was also suggested in one of the previous review rounds; the other functions already follow that model, so this keeps functions symmetrical looking. gas/ * gas/config/tc-i386.c (x86_ginsn_lea): Handle select lea ops with no base register similar to the case of no index register. Remove creation of GINSN_TYPE_OTHER from the function. gas/testsuite/ * gas/scfi/x86_64/ginsn-lea-1.l: New test. * gas/scfi/x86_64/ginsn-lea-1.s: Likewise. * gas/scfi/x86_64/scfi-x86-64.exp: Add new test.

Bug PR gdb/28313 describes attaching to a process when the executable has been deleted. The bug is for S390 and describes how a user sees a message 'PC not saved'. On x86-64 (GNU/Linux) I don't see a 'PC not saved' message, but instead I see this: (gdb) attach 901877 Attaching to process 901877 No executable file now. warning: Could not load vsyscall page because no executable was specified 0x00007fa9d9c121e7 in ?? () (gdb) bt #0 0x00007fa9d9c121e7 in ?? () devkitPro#1 0x00007fa9d9c1211e in ?? () devkitPro#2 0x0000000000000007 in ?? () bminor#3 0x000000002dc8b18d in ?? () bminor#4 0x0000000000000000 in ?? () (gdb) Notice that the addresses in the backtrace don't seem right, quickly heading to 0x7 and finally ending at 0x0. What's going on, in both the s390 case and the x86-64 case is that the architecture's prologue scanner is going wrong and causing the stack unwinding to fail. The prologue scanner goes wrong because GDB has no unwind information. And GDB has no unwind information because, of course, the executable has been deleted. Notice in the example session above we get this line in the output: No executable file now. which indicates that GDB failed to find an executable to debug. For GNU/Linux when GDB tries to find an executable for a given pid we end up calling linux_proc_pid_to_exec_file in gdb/nat/linux-procfs.c. Within this function we call `readlink` on /proc/PID/exe to find the path of the actual executable. If the `readlink` call fails then we already fallback on using /proc/PID/exe as the path to the executable to debug. However, when the executable has been deleted the `readlink` call doesn't fail, but the path that is returned points to a non-existent file. I propose that we add an `access` call to linux_proc_pid_to_exec_file to check that the target file exists and can be read. If the target can't be read then we should fall back to /proc/PID/exe (assuming that /proc/PID/exe can be read). Now on x86-64 the output looks like this: (gdb) attach 901877 Attaching to process 901877 Reading symbols from /proc/901877/exe... Reading symbols from /lib64/libc.so.6... (No debugging symbols found in /lib64/libc.so.6) Reading symbols from /lib64/ld-linux-x86-64.so.2... (No debugging symbols found in /lib64/ld-linux-x86-64.so.2) 0x00007fa9d9c121e7 in nanosleep () from /lib64/libc.so.6 (gdb) bt #0 0x00007fa9d9c121e7 in nanosleep () from /lib64/libc.so.6 devkitPro#1 0x00007fa9d9c1211e in sleep () from /lib64/libc.so.6 devkitPro#2 0x000000000040117e in spin_forever () at attach-test.c:17 bminor#3 0x0000000000401198 in main () at attach-test.c:24 (gdb) which is much better. I've also tagged the bug PR gdb/29782 which concerns the test gdb.server/connect-with-no-symbol-file.exp. After making this change, when running gdb.server/connect-with-no-symbol-file.exp GDB would now pick up the /proc/PID/exe file as the executable in some cases. As GDB is not restarted for the multiple iterations of this test GDB (or rather BFD) would given a warning/error like: (gdb) PASS: gdb.server/connect-with-no-symbol-file.exp: sysroot=target:: action=permission: setup: disconnect set sysroot target: BFD: reopening /proc/3283001/exe: No such file or directory (gdb) FAIL: gdb.server/connect-with-no-symbol-file.exp: sysroot=target:: action=permission: setup: adjust sysroot What's happening is that an executable found for an earlier iteration of the test is still registered for the inferior when we are setting up for a second iteration of the test. When the sysroot changes, if there's an executable registered GDB tries to reopen it, but in this case the file has disappeared (the previous inferior has exited by this point). I did think about maybe, when the executable is /proc/PID/exe, we should auto-delete the file from the inferior. But in the end I thought this was a bad idea. Not only would this require a lot of special code in GDB just to support this edge case: we'd need to track if the exe file name came from /proc and should be auto-deleted, or we'd need target specific code to check if a path should be auto-deleted..... ... in addition, we'd still want to warn the user when we auto-deleted the file from the inferior, otherwise they might be surprised to find their inferior suddenly has no executable attached, so we wouldn't actually reduce the number of warnings the user sees. So in the end I figured that the best solution is to just update the test to avoid the warning. This is easily done by manually removing the executable from the inferior once each iteration of the test has completed. Now, in bug PR gdb/29782 GDB is clearly managing to pick up an executable from the NFS cache somehow. I guess what's happening is that when the original file is deleted /proc/PID/exe is actually pointing to a file in the NFS cache which is only deleted at some later point, and so when GDB starts up we do manage to associate a file with the inferior, this results in the same message being emitted from BFD as I was seeing. The fix included in this commit should also fix that bug. One final note: On x86-64 GNU/Linux, the gdb.server/connect-with-no-symbol-file.exp test will produce 2 core files. This is due to a bug in gdbserver that is nothing to do with this test. These core files are created before and after this commit. I am working on a fix for the gdbserver issue, but will post that separately. Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=28313 Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=29782 Approved-By: Tom Tromey <tom@tromey.com>

When running test-case gdb.dap/eof.exp, it occasionally coredumps. The thread triggering the coredump is: ... #0 0x0000ffff42bb2280 in __pthread_kill_implementation () from /lib64/libc.so.6 devkitPro#1 0x0000ffff42b65800 [PAC] in raise () from /lib64/libc.so.6 devkitPro#2 0x00000000007b03e8 [PAC] in handle_fatal_signal (sig=11) at gdb/event-top.c:926 bminor#3 0x00000000007b0470 in handle_sigsegv (sig=11) at gdb/event-top.c:976 bminor#4 <signal handler called> bminor#5 0x0000000000606080 in cli_ui_out::do_message (this=0xffff2f7ed728, style=..., format=0xffff0c002af1 "%s", args=...) at gdb/cli-out.c:232 bminor#6 0x0000000000ce6358 in ui_out::call_do_message (this=0xffff2f7ed728, style=..., format=0xffff0c002af1 "%s") at gdb/ui-out.c:584 bminor#7 0x0000000000ce6610 in ui_out::vmessage (this=0xffff2f7ed728, in_style=..., format=0x16f93ea "", args=...) at gdb/ui-out.c:621 bminor#8 0x0000000000ce3a9c in ui_file::vprintf (this=0xfffffbea1b18, ...) at gdb/ui-file.c:74 bminor#9 0x0000000000d2b148 in gdb_vprintf (stream=0xfffffbea1b18, format=0x16f93e8 "%s", args=...) at gdb/utils.c:1898 bminor#10 0x0000000000d2b23c in gdb_printf (stream=0xfffffbea1b18, format=0x16f93e8 "%s") at gdb/utils.c:1913 bminor#11 0x0000000000ab5208 in gdbpy_write (self=0x33fe35d0, args=0x342ec280, kw=0x345c08b0) at gdb/python/python.c:1464 bminor#12 0x0000ffff434acedc in cfunction_call () from /lib64/libpython3.12.so.1.0 #13 0x0000ffff4347c500 [PAC] in _PyObject_MakeTpCall () from /lib64/libpython3.12.so.1.0 #14 0x0000ffff43488b64 [PAC] in _PyEval_EvalFrameDefault () from /lib64/libpython3.12.so.1.0 #15 0x0000ffff434d8cd0 [PAC] in method_vectorcall () from /lib64/libpython3.12.so.1.0 #16 0x0000ffff434b9824 [PAC] in PyObject_CallOneArg () from /lib64/libpython3.12.so.1.0 #17 0x0000ffff43557674 [PAC] in PyFile_WriteObject () from /lib64/libpython3.12.so.1.0 #18 0x0000ffff435577a0 [PAC] in PyFile_WriteString () from /lib64/libpython3.12.so.1.0 #19 0x0000ffff43465354 [PAC] in thread_excepthook () from /lib64/libpython3.12.so.1.0 #20 0x0000ffff434ac6e0 [PAC] in cfunction_vectorcall_O () from /lib64/libpython3.12.so.1.0 #21 0x0000ffff434a32d8 [PAC] in PyObject_Vectorcall () from /lib64/libpython3.12.so.1.0 #22 0x0000ffff43488b64 [PAC] in _PyEval_EvalFrameDefault () from /lib64/libpython3.12.so.1.0 #23 0x0000ffff434d8d88 [PAC] in method_vectorcall () from /lib64/libpython3.12.so.1.0 #24 0x0000ffff435e0ef4 [PAC] in thread_run () from /lib64/libpython3.12.so.1.0 #25 0x0000ffff43591ec0 [PAC] in pythread_wrapper () from /lib64/libpython3.12.so.1.0 #26 0x0000ffff42bb0584 [PAC] in start_thread () from /lib64/libc.so.6 #27 0x0000ffff42c1fd4c [PAC] in thread_start () from /lib64/libc.so.6 ... The direct cause for the coredump seems to be that cli_ui_out::do_message is trying to write to a stream variable which does not look sound: ... (gdb) p *stream $8 = {_vptr.ui_file = 0x0, m_applied_style = {m_foreground = {m_simple = true, { m_value = 0, {m_red = 0 '\000', m_green = 0 '\000', m_blue = 0 '\000'}}}, m_background = {m_simple = 32, {m_value = 65535, {m_red = 255 '\377', m_green = 255 '\377', m_blue = 0 '\000'}}}, m_intensity = (unknown: 0x438fe710), m_reverse = 255}} ... The string that is being printed is: ... (gdb) p str $9 = "Exception in thread " ... so AFAICT this is a DAP thread running into an exception and trying to print it. If we look at the state of gdb's main thread, we have: ... #0 0x0000ffff42bac914 in __futex_abstimed_wait_cancelable64 () from /lib64/libc.so.6 devkitPro#1 0x0000ffff42bafb44 [PAC] in pthread_cond_timedwait@@GLIBC_2.17 () from /lib64/libc.so.6 devkitPro#2 0x0000ffff43466e9c [PAC] in take_gil () from /lib64/libpython3.12.so.1.0 bminor#3 0x0000ffff43484fe0 [PAC] in PyEval_RestoreThread () from /lib64/libpython3.12.so.1.0 bminor#4 0x0000000000ab8698 [PAC] in gdbpy_allow_threads::~gdbpy_allow_threads ( this=0xfffffbea1cf8, __in_chrg=<optimized out>) at gdb/python/python-internal.h:769 bminor#5 0x0000000000ab2fec in execute_gdb_command (self=0x33fe35d0, args=0x34297b60, kw=0x34553d20) at gdb/python/python.c:681 bminor#6 0x0000ffff434acedc in cfunction_call () from /lib64/libpython3.12.so.1.0 bminor#7 0x0000ffff4347c500 [PAC] in _PyObject_MakeTpCall () from /lib64/libpython3.12.so.1.0 bminor#8 0x0000ffff43488b64 [PAC] in _PyEval_EvalFrameDefault () from /lib64/libpython3.12.so.1.0 bminor#9 0x0000ffff4353bce8 [PAC] in _PyObject_VectorcallTstate.lto_priv.3 () from /lib64/libpython3.12.so.1.0 bminor#10 0x0000000000ab87fc [PAC] in gdbpy_event::operator() (this=0xffff14005900) at gdb/python/python.c:1061 bminor#11 0x0000000000ab93e8 in std::__invoke_impl<void, gdbpy_event&> (__f=...) at /usr/include/c++/13/bits/invoke.h:61 bminor#12 0x0000000000ab9204 in std::__invoke_r<void, gdbpy_event&> (__fn=...) at /usr/include/c++/13/bits/invoke.h:111 #13 0x0000000000ab8e90 in std::_Function_handler<..>::_M_invoke(...) (...) at /usr/include/c++/13/bits/std_function.h:290 #14 0x000000000062e0d0 in std::function<void ()>::operator()() const ( this=0xffff14005830) at /usr/include/c++/13/bits/std_function.h:591 #15 0x0000000000b67f14 in run_events (error=0, client_data=0x0) at gdb/run-on-main-thread.c:76 #16 0x000000000157e290 in handle_file_event (file_ptr=0x33dae3a0, ready_mask=1) at gdbsupport/event-loop.cc:573 #17 0x000000000157e760 in gdb_wait_for_event (block=1) at gdbsupport/event-loop.cc:694 #18 0x000000000157d464 in gdb_do_one_event (mstimeout=-1) at gdbsupport/event-loop.cc:264 #19 0x0000000000943a84 in start_event_loop () at gdb/main.c:401 #20 0x0000000000943bfc in captured_command_loop () at gdb/main.c:465 #21 0x000000000094567c in captured_main (data=0xfffffbea23e8) at gdb/main.c:1335 #22 0x0000000000945700 in gdb_main (args=0xfffffbea23e8) at gdb/main.c:1354 #23 0x0000000000423ab4 in main (argc=14, argv=0xfffffbea2578) at gdb/gdb.c:39 ... AFAIU, there's a race between the two threads on gdb_stderr: - the DAP thread samples the gdb_stderr value, and uses it a bit later to print to - the gdb main thread changes the gdb_stderr value forth and back, using a temporary value for string capture purposes The non-sound stream value is caused by gdb_stderr being sampled while pointing to a str_file object, and used once the str_file object is already destroyed. The error here is that the DAP thread attempts to print to gdb_stderr. Fix this by adding a thread_wrapper that: - catches all exceptions and logs them to dap.log, and - while we're at it, logs when exiting and using the thread_wrapper for each DAP thread. Tested on aarch64-linux. Approved-By: Tom Tromey <tom@tromey.com>

When running test-case gdb.dap/eof.exp, we're likely to get a coredump due to a segfault in new_threadstate. At the point of the core dump, the gdb main thread looks like: ... (gdb) bt #0 0x0000fffee30d2280 in __pthread_kill_implementation () from /lib64/libc.so.6 devkitPro#1 0x0000fffee3085800 [PAC] in raise () from /lib64/libc.so.6 devkitPro#2 0x00000000007b03e8 [PAC] in handle_fatal_signal (sig=11) at gdb/event-top.c:926 bminor#3 0x00000000007b0470 in handle_sigsegv (sig=11) at gdb/event-top.c:976 bminor#4 <signal handler called> bminor#5 0x0000fffee3a4db14 in new_threadstate () from /lib64/libpython3.12.so.1.0 bminor#6 0x0000fffee3ab0548 [PAC] in PyGILState_Ensure () from /lib64/libpython3.12.so.1.0 bminor#7 0x0000000000a6d034 [PAC] in gdbpy_gil::gdbpy_gil (this=0xffffcb279738) at gdb/python/python-internal.h:787 bminor#8 0x0000000000ab87ac in gdbpy_event::~gdbpy_event (this=0xfffea8001ee0, __in_chrg=<optimized out>) at gdb/python/python.c:1051 bminor#9 0x0000000000ab9460 in std::_Function_base::_Base_manager<...>::_M_destroy (__victim=...) at /usr/include/c++/13/bits/std_function.h:175 bminor#10 0x0000000000ab92dc in std::_Function_base::_Base_manager<...>::_M_manager (__dest=..., __source=..., __op=std::__destroy_functor) at /usr/include/c++/13/bits/std_function.h:203 bminor#11 0x0000000000ab8f14 in std::_Function_handler<...>::_M_manager(...) (...) at /usr/include/c++/13/bits/std_function.h:282 bminor#12 0x000000000042dd9c in std::_Function_base::~_Function_base (this=0xfffea8001c10, __in_chrg=<optimized out>) at /usr/include/c++/13/bits/std_function.h:244 #13 0x000000000042e654 in std::function<void ()>::~function() (this=0xfffea8001c10, __in_chrg=<optimized out>) at /usr/include/c++/13/bits/std_function.h:334 #14 0x0000000000b68e60 in std::_Destroy<std::function<void ()> >(...) (...) at /usr/include/c++/13/bits/stl_construct.h:151 #15 0x0000000000b68cd0 in std::_Destroy_aux<false>::__destroy<...>(...) (...) at /usr/include/c++/13/bits/stl_construct.h:163 #16 0x0000000000b689d8 in std::_Destroy<...>(...) (...) at /usr/include/c++/13/bits/stl_construct.h:196 #17 0x0000000000b68414 in std::_Destroy<...>(...) (...) at /usr/include/c++/13/bits/alloc_traits.h:948 #18 std::vector<...>::~vector() (this=0x2a183c8 <runnables>) at /usr/include/c++/13/bits/stl_vector.h:732 #19 0x0000fffee3088370 in __run_exit_handlers () from /lib64/libc.so.6 #20 0x0000fffee3088450 [PAC] in exit () from /lib64/libc.so.6 #21 0x0000000000c95600 [PAC] in quit_force (exit_arg=0x0, from_tty=0) at gdb/top.c:1822 #22 0x0000000000609140 in quit_command (args=0x0, from_tty=0) at gdb/cli/cli-cmds.c:508 #23 0x0000000000c926a4 in quit_cover () at gdb/top.c:300 #24 0x00000000007b09d4 in async_disconnect (arg=0x0) at gdb/event-top.c:1230 #25 0x0000000000548acc in invoke_async_signal_handlers () at gdb/async-event.c:234 #26 0x000000000157d2d4 in gdb_do_one_event (mstimeout=-1) at gdbsupport/event-loop.cc:199 #27 0x0000000000943a84 in start_event_loop () at gdb/main.c:401 #28 0x0000000000943bfc in captured_command_loop () at gdb/main.c:465 #29 0x000000000094567c in captured_main (data=0xffffcb279d08) at gdb/main.c:1335 #30 0x0000000000945700 in gdb_main (args=0xffffcb279d08) at gdb/main.c:1354 #31 0x0000000000423ab4 in main (argc=14, argv=0xffffcb279e98) at gdb/gdb.c:39 ... The direct cause of the segfault is calling PyGILState_Ensure after calling Py_Finalize. AFAICT the problem is a race between the gdb main thread and DAP's JSON writer thread. On one side, we have the following events: - DAP's JSON reader thread reads an EOF, and lets DAP's main thread known by writing None into read_queue - DAP's main thread lets DAP's JSON writer thread known by writing None into write_queue - DAP's JSON writer thread sees the None in its queue, and calls send_gdb("quit") - a corresponding gdbpy_event is deposited in the runnables vector, to be run by the gdb main thread On the other side, we have the following events: - the gdb main thread receives a SIGHUP - the corresponding handler calls quit_force, which calls do_final_cleanups - one of the final cleanups is finalize_python, which calls Py_Finalize - quit_force calls exit, which triggers the exit handlers - one of the exit handlers is the destructor of the runnables vector - destruction of the vector triggers destruction of the remaining element - the remaining element is a gdbpy_event, and the destructor (indirectly) calls PyGILState_Ensure It's good to note that both events (EOF and SIGHUP) are caused by this line in the test-case: ... catch "close -i $gdb_spawn_id" ... where "expect close" closes the stdin and stdout file descriptors, which causes the SIGHUP to be send. So, for the system I'm running this on, the send_gdb("quit") is actually not needed. I'm not sure if we support any systems where it's actually needed. Fix this by removing the send_gdb("quit"). Tested on aarch64-linux. PR dap/31306 Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=31306

When building gdb with -O0 -fsanitize=address, and running test-case gdb.ada/uninitialized_vars.exp, I run into: ... (gdb) info locals a = 0 z = (a => 1, b => false, c => 2.0) ================================================================= ==66372==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x602000097f58 at pc 0xffff52c0da1c bp 0xffffc90a1d40 sp 0xffffc90a1d80 READ of size 4 at 0x602000097f58 thread T0 #0 0xffff52c0da18 in memmove (/lib64/libasan.so.8+0x6da18) devkitPro#1 0xbcab24 in unsigned char* std::__copy_move_backward<false, true, std::random_access_iterator_tag>::__copy_move_b<unsigned char const, unsigned char>(unsigned char const*, unsigned char const*, unsigned char*) /usr/include/c++/13/bits/stl_algobase.h:748 devkitPro#2 0xbc9bf4 in unsigned char* std::__copy_move_backward_a2<false, unsigned char const*, unsigned char*>(unsigned char const*, unsigned char const*, unsigned char*) /usr/include/c++/13/bits/stl_algobase.h:769 bminor#3 0xbc898c in unsigned char* std::__copy_move_backward_a1<false, unsigned char const*, unsigned char*>(unsigned char const*, unsigned char const*, unsigned char*) /usr/include/c++/13/bits/stl_algobase.h:778 bminor#4 0xbc715c in unsigned char* std::__copy_move_backward_a<false, unsigned char const*, unsigned char*>(unsigned char const*, unsigned char const*, unsigned char*) /usr/include/c++/13/bits/stl_algobase.h:807 bminor#5 0xbc4e6c in unsigned char* std::copy_backward<unsigned char const*, unsigned char*>(unsigned char const*, unsigned char const*, unsigned char*) /usr/include/c++/13/bits/stl_algobase.h:867 bminor#6 0xbc2934 in void gdb::copy<unsigned char const, unsigned char>(gdb::array_view<unsigned char const>, gdb::array_view<unsigned char>) gdb/../gdbsupport/array-view.h:223 bminor#7 0x20e0100 in value::contents_copy_raw(value*, long, long, long) gdb/value.c:1239 bminor#8 0x20e9830 in value::primitive_field(long, int, type*) gdb/value.c:3078 bminor#9 0x20e98f8 in value_field(value*, int) gdb/value.c:3095 bminor#10 0xcafd64 in print_field_values gdb/ada-valprint.c:658 bminor#11 0xcb0fa0 in ada_val_print_struct_union gdb/ada-valprint.c:857 bminor#12 0xcb1bb4 in ada_value_print_inner(value*, ui_file*, int, value_print_options const*) gdb/ada-valprint.c:1042 #13 0xc66e04 in ada_language::value_print_inner(value*, ui_file*, int, value_print_options const*) const (/home/vries/gdb/build/gdb/gdb+0xc66e04) #14 0x20ca1e8 in common_val_print(value*, ui_file*, int, value_print_options const*, language_defn const*) gdb/valprint.c:1092 #15 0x20caabc in common_val_print_checked(value*, ui_file*, int, value_print_options const*, language_defn const*) gdb/valprint.c:1184 #16 0x196c524 in print_variable_and_value(char const*, symbol*, frame_info_ptr, ui_file*, int) gdb/printcmd.c:2355 #17 0x1d99ca0 in print_variable_and_value_data::operator()(char const*, symbol*) gdb/stack.c:2308 #18 0x1dabca0 in gdb::function_view<void (char const*, symbol*)>::bind<print_variable_and_value_data>(print_variable_and_value_data&)::{lambda(gdb::fv_detail::erased_callable, char const*, symbol*)devkitPro#1}::operator()(gdb::fv_detail::erased_callable, char const*, symbol*) const gdb/../gdbsupport/function-view.h:305 #19 0x1dabd14 in gdb::function_view<void (char const*, symbol*)>::bind<print_variable_and_value_data>(print_variable_and_value_data&)::{lambda(gdb::fv_detail::erased_callable, char const*, symbol*)devkitPro#1}::_FUN(gdb::fv_detail::erased_callable, char const*, symbol*) gdb/../gdbsupport/function-view.h:299 #20 0x1dab34c in gdb::function_view<void (char const*, symbol*)>::operator()(char const*, symbol*) const gdb/../gdbsupport/function-view.h:289 #21 0x1d9963c in iterate_over_block_locals gdb/stack.c:2240 #22 0x1d99790 in iterate_over_block_local_vars(block const*, gdb::function_view<void (char const*, symbol*)>) gdb/stack.c:2259 #23 0x1d9a598 in print_frame_local_vars gdb/stack.c:2380 #24 0x1d9afac in info_locals_command(char const*, int) gdb/stack.c:2458 #25 0xfd7b30 in do_simple_func gdb/cli/cli-decode.c:95 #26 0xfe5a2c in cmd_func(cmd_list_element*, char const*, int) gdb/cli/cli-decode.c:2735 #27 0x1f03790 in execute_command(char const*, int) gdb/top.c:575 #28 0x1384080 in command_handler(char const*) gdb/event-top.c:566 #29 0x1384e2c in command_line_handler(std::unique_ptr<char, gdb::xfree_deleter<char> >&&) gdb/event-top.c:802 #30 0x1f731e4 in tui_command_line_handler gdb/tui/tui-interp.c:104 #31 0x1382a58 in gdb_rl_callback_handler gdb/event-top.c:259 #32 0x21dbb80 in rl_callback_read_char readline/readline/callback.c:290 #33 0x1382510 in gdb_rl_callback_read_char_wrapper_noexcept gdb/event-top.c:195 #34 0x138277c in gdb_rl_callback_read_char_wrapper gdb/event-top.c:234 #35 0x1fe9b40 in stdin_event_handler gdb/ui.c:155 #36 0x35ff1bc in handle_file_event gdbsupport/event-loop.cc:573 #37 0x35ff9d8 in gdb_wait_for_event gdbsupport/event-loop.cc:694 #38 0x35fd284 in gdb_do_one_event(int) gdbsupport/event-loop.cc:264 #39 0x1768080 in start_event_loop gdb/main.c:408 #40 0x17684c4 in captured_command_loop gdb/main.c:472 #41 0x176cfc8 in captured_main gdb/main.c:1342 #42 0x176d088 in gdb_main(captured_main_args*) gdb/main.c:1361 #43 0xb73edc in main gdb/gdb.c:39 #44 0xffff519b09d8 in __libc_start_call_main (/lib64/libc.so.6+0x309d8) #45 0xffff519b0aac in __libc_start_main@@GLIBC_2.34 (/lib64/libc.so.6+0x30aac) #46 0xb73c2c in _start (/home/vries/gdb/build/gdb/gdb+0xb73c2c) 0x602000097f58 is located 0 bytes after 8-byte region [0x602000097f50,0x602000097f58) allocated by thread T0 here: #0 0xffff52c65218 in calloc (/lib64/libasan.so.8+0xc5218) devkitPro#1 0xcbc278 in xcalloc gdb/alloc.c:97 devkitPro#2 0x35f21e8 in xzalloc(unsigned long) gdbsupport/common-utils.cc:29 bminor#3 0x20de270 in value::allocate_contents(bool) gdb/value.c:937 bminor#4 0x20edc08 in value::fetch_lazy() gdb/value.c:4033 bminor#5 0x20dadc0 in value::entirely_covered_by_range_vector(std::vector<range, std::allocator<range> > const&) gdb/value.c:229 bminor#6 0xcb2298 in value::entirely_optimized_out() gdb/value.h:560 bminor#7 0x20ca6fc in value_check_printable gdb/valprint.c:1133 bminor#8 0x20caa8c in common_val_print_checked(value*, ui_file*, int, value_print_options const*, language_defn const*) gdb/valprint.c:1182 bminor#9 0x196c524 in print_variable_and_value(char const*, symbol*, frame_info_ptr, ui_file*, int) gdb/printcmd.c:2355 bminor#10 0x1d99ca0 in print_variable_and_value_data::operator()(char const*, symbol*) gdb/stack.c:2308 bminor#11 0x1dabca0 in gdb::function_view<void (char const*, symbol*)>::bind<print_variable_and_value_data>(print_variable_and_value_data&)::{lambda(gdb::fv_detail::erased_callable, char const*, symbol*)devkitPro#1}::operator()(gdb::fv_detail::erased_callable, char const*, symbol*) const gdb/../gdbsupport/function-view.h:305 bminor#12 0x1dabd14 in gdb::function_view<void (char const*, symbol*)>::bind<print_variable_and_value_data>(print_variable_and_value_data&)::{lambda(gdb::fv_detail::erased_callable, char const*, symbol*)devkitPro#1}::_FUN(gdb::fv_detail::erased_callable, char const*, symbol*) gdb/../gdbsupport/function-view.h:299 #13 0x1dab34c in gdb::function_view<void (char const*, symbol*)>::operator()(char const*, symbol*) const gdb/../gdbsupport/function-view.h:289 #14 0x1d9963c in iterate_over_block_locals gdb/stack.c:2240 #15 0x1d99790 in iterate_over_block_local_vars(block const*, gdb::function_view<void (char const*, symbol*)>) gdb/stack.c:2259 #16 0x1d9a598 in print_frame_local_vars gdb/stack.c:2380 #17 0x1d9afac in info_locals_command(char const*, int) gdb/stack.c:2458 #18 0xfd7b30 in do_simple_func gdb/cli/cli-decode.c:95 #19 0xfe5a2c in cmd_func(cmd_list_element*, char const*, int) gdb/cli/cli-decode.c:2735 #20 0x1f03790 in execute_command(char const*, int) gdb/top.c:575 #21 0x1384080 in command_handler(char const*) gdb/event-top.c:566 #22 0x1384e2c in command_line_handler(std::unique_ptr<char, gdb::xfree_deleter<char> >&&) gdb/event-top.c:802 #23 0x1f731e4 in tui_command_line_handler gdb/tui/tui-interp.c:104 #24 0x1382a58 in gdb_rl_callback_handler gdb/event-top.c:259 #25 0x21dbb80 in rl_callback_read_char readline/readline/callback.c:290 #26 0x1382510 in gdb_rl_callback_read_char_wrapper_noexcept gdb/event-top.c:195 #27 0x138277c in gdb_rl_callback_read_char_wrapper gdb/event-top.c:234 #28 0x1fe9b40 in stdin_event_handler gdb/ui.c:155 #29 0x35ff1bc in handle_file_event gdbsupport/event-loop.cc:573 SUMMARY: AddressSanitizer: heap-buffer-overflow (/lib64/libasan.so.8+0x6da18) in memmove ... The error happens when trying to print either variable y or y2: ... type Variable_Record (A : Boolean := True) is record case A is when True => B : Integer; when False => C : Float; D : Integer; end case; end record; Y : Variable_Record := (A => True, B => 1); Y2 : Variable_Record := (A => False, C => 1.0, D => 2); ... when the variables are uninitialized. The error happens only when printing the entire variable: ... (gdb) p y.a $2 = 216 (gdb) p y.b There is no member named b. (gdb) p y.c $3 = 9.18340949e-41 (gdb) p y.d $4 = 1 (gdb) p y <AddressSanitizer: heap-buffer-overflow> ... The error happens as follows: - field a functions as discriminant, choosing either the b, or c+d variant. - when y.a happens to be set to 216, as above, gdb interprets this as the variable having the c+d variant (which is why trying to print y.b fails). - when printing y, gdb allocates a value, copies the bytes into it from the target, and then prints the value. - gdb allocates the value using the type size, which is 8. It's 8 because that's what the DW_AT_byte_size indicates. Note that for valid values of a, it gives correct results: if a is 0 (c+d variant), size is 12, if a is 1 (b variant), size is 8. - gdb tries to print field d, which is at an 8 byte offset, and that results in a out-of-bounds access for the allocated 8-byte value. Fix this by handling this case in value::contents_copy_raw, such that we have: ... (gdb) p y $1 = (a => 24, c => 9.18340949e-41, d => <error reading variable: access outside bounds of object>) ... An alternative (additional) fix could be this: in compute_variant_fields_inner gdb reads the discriminant y.a to decide which variant is active. It would be nice to detect that the value (y.a == 24) is not a valid Boolean, and give up on choosing a variant altoghether. However, the situation regarding the internal type CODE_TYPE_BOOL is currently ambiguous (see PR31282) and it's not possible to reliably decide what valid values are. The test-case source file gdb.ada/uninitialized-variable-record/parse.adb is a reduced version of gdb.ada/uninitialized_vars/parse.adb, so it copies the copyright years. Note that the test-case needs gcc-12 or newer, it's unsupported for older gcc versions. [ So, it would be nice to rewrite it into a dwarf assembly test-case. ] The test-case loops over all languages. This is inherited from an earlier attempt to fix this, which had language-specific fixes (in print_field_values, cp_print_value_fields, pascal_object_print_value_fields and f_language::value_print_inner). I've left this in, but I suppose it's not strictly necessary anymore. Tested on x86_64-linux. PR exp/31258 Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=31258

From the Python API, we can execute GDB commands via gdb.execute. If the command gives an exception, however, we need to recover the GDB prompt and enable stdin, because the exception does not reach top-level GDB or normal_stop. This was done in commit commit 1ba1ac8 Author: Andrew Burgess <andrew.burgess@embecosm.com> Date: Tue Nov 19 11:17:20 2019 +0000 gdb: Enable stdin on exception in execute_gdb_command with the following code: catch (const gdb_exception &except) { /* If an exception occurred then we won't hit normal_stop (), or have an exception reach the top level of the event loop, which are the two usual places in which stdin would be re-enabled. So, before we convert the exception and continue back in Python, we should re-enable stdin here. */ async_enable_stdin (); GDB_PY_HANDLE_EXCEPTION (except); } In this patch, we explain what happens when we run a GDB command in the context of a synchronous command, e.g. via Python observer notifications. As an example, suppose we have the following objfile event listener, specified in a file named file.py: ~~~ import gdb class MyListener: def __init__(self): gdb.events.new_objfile.connect(self.handle_new_objfile_event) self.processed_objfile = False def handle_new_objfile_event(self, event): if self.processed_objfile: return print("loading " + event.new_objfile.filename) self.processed_objfile = True gdb.execute('add-inferior -no-connection') gdb.execute('inferior 2') gdb.execute('target remote | gdbserver - /tmp/a.out') gdb.execute('inferior 1') the_listener = MyListener() ~~~ Using this Python file, we see the behavior below: $ gdb -q -ex "source file.py" -ex "run" --args a.out Reading symbols from a.out... Starting program: /tmp/a.out loading /lib64/ld-linux-x86-64.so.2 [New inferior 2] Added inferior 2 [Switching to inferior 2 [<null>] (<noexec>)] stdin/stdout redirected Process /tmp/a.out created; pid = 3075406 Remote debugging using stdio Reading /tmp/a.out from remote target... ... [Switching to inferior 1 [process 3075400] (/tmp/a.out)] [Switching to thread 1.1 (process 3075400)] #0 0x00007ffff7fe3290 in ?? () from /lib64/ld-linux-x86-64.so.2 (gdb) [Thread debugging using libthread_db enabled] Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1". [Inferior 1 (process 3075400) exited normally] Note how the GDB prompt comes in-between the debugger output. We have this obscure behavior, because the executed command, "target remote", triggers an invocation of `normal_stop` that enables stdin. After that, however, the Python notification context completes and GDB continues with its normal flow of executing the 'run' command. This can be seen in the call stack below: (top-gdb) bt #0 async_enable_stdin () at src/gdb/event-top.c:523 devkitPro#1 0x00005555561c3acd in normal_stop () at src/gdb/infrun.c:9432 devkitPro#2 0x00005555561b328e in start_remote (from_tty=0) at src/gdb/infrun.c:3801 bminor#3 0x0000555556441224 in remote_target::start_remote_1 (this=0x5555587882e0, from_tty=0, extended_p=0) at src/gdb/remote.c:5225 bminor#4 0x000055555644166c in remote_target::start_remote (this=0x5555587882e0, from_tty=0, extended_p=0) at src/gdb/remote.c:5316 bminor#5 0x00005555564430cf in remote_target::open_1 (name=0x55555878525e "| gdbserver - /tmp/a.out", from_tty=0, extended_p=0) at src/gdb/remote.c:6175 bminor#6 0x0000555556441707 in remote_target::open (name=0x55555878525e "| gdbserver - /tmp/a.out", from_tty=0) at src/gdb/remote.c:5338 bminor#7 0x00005555565ea63f in open_target (args=0x55555878525e "| gdbserver - /tmp/a.out", from_tty=0, command=0x555558589280) at src/gdb/target.c:824 bminor#8 0x0000555555f0d89a in cmd_func (cmd=0x555558589280, args=0x55555878525e "| gdbserver - /tmp/a.out", from_tty=0) at src/gdb/cli/cli-decode.c:2735 bminor#9 0x000055555661fb42 in execute_command (p=0x55555878529e "t", from_tty=0) at src/gdb/top.c:575 bminor#10 0x0000555555f1a506 in execute_control_command_1 (cmd=0x555558756f00, from_tty=0) at src/gdb/cli/cli-script.c:529 bminor#11 0x0000555555f1abea in execute_control_command (cmd=0x555558756f00, from_tty=0) at src/gdb/cli/cli-script.c:701 bminor#12 0x0000555555f19fc7 in execute_control_commands (cmdlines=0x555558756f00, from_tty=0) at src/gdb/cli/cli-script.c:411 #13 0x0000555556400d91 in execute_gdb_command (self=0x7ffff43b5d00, args=0x7ffff440ab60, kw=0x0) at src/gdb/python/python.c:700 #14 0x00007ffff7a96023 in ?? () from /lib/x86_64-linux-gnu/libpython3.10.so.1.0 #15 0x00007ffff7a4dadc in _PyObject_MakeTpCall () from /lib/x86_64-linux-gnu/libpython3.10.so.1.0 #16 0x00007ffff79e9a1c in _PyEval_EvalFrameDefault () from /lib/x86_64-linux-gnu/libpython3.10.so.1.0 #17 0x00007ffff7b303af in ?? () from /lib/x86_64-linux-gnu/libpython3.10.so.1.0 #18 0x00007ffff7a50358 in ?? () from /lib/x86_64-linux-gnu/libpython3.10.so.1.0 #19 0x00007ffff7a4f3f4 in ?? () from /lib/x86_64-linux-gnu/libpython3.10.so.1.0 #20 0x00007ffff7a4f883 in PyObject_CallFunctionObjArgs () from /lib/x86_64-linux-gnu/libpython3.10.so.1.0 #21 0x00005555563a9758 in evpy_emit_event (event=0x7ffff42b5430, registry=0x7ffff42b4690) at src/gdb/python/py-event.c:104 #22 0x00005555563cb874 in emit_new_objfile_event (objfile=0x555558761700) at src/gdb/python/py-newobjfileevent.c:52 #23 0x00005555563b53bc in python_new_objfile (objfile=0x555558761700) at src/gdb/python/py-inferior.c:195 #24 0x0000555555d6dff0 in std::__invoke_impl<void, void (*&)(objfile*), objfile*> (__f=@0x5555585b5860: 0x5555563b5360 <python_new_objfile(objfile*)>) at /usr/include/c++/11/bits/invoke.h:61 #25 0x0000555555d6be18 in std::__invoke_r<void, void (*&)(objfile*), objfile*> (__fn=@0x5555585b5860: 0x5555563b5360 <python_new_objfile(objfile*)>) at /usr/include/c++/11/bits/invoke.h:111 #26 0x0000555555d69661 in std::_Function_handler<void (objfile*), void (*)(objfile*)>::_M_invoke(std::_Any_data const&, objfile*&&) (__functor=..., __args#0=@0x7fffffffd080: 0x555558761700) at /usr/include/c++/11/bits/std_function.h:290 #27 0x0000555556314caf in std::function<void (objfile*)>::operator()(objfile*) const (this=0x5555585b5860, __args#0=0x555558761700) at /usr/include/c++/11/bits/std_function.h:590 #28 0x000055555631444e in gdb::observers::observable<objfile*>::notify (this=0x55555836eea0 <gdb::observers::new_objfile>, args#0=0x555558761700) at src/gdb/../gdbsupport/observable.h:166 #29 0x0000555556599b3f in symbol_file_add_with_addrs (abfd=..., name=0x55555875d310 "/lib64/ld-linux-x86-64.so.2", add_flags=..., addrs=0x7fffffffd2f0, flags=..., parent=0x0) at src/gdb/symfile.c:1125 #30 0x0000555556599ca4 in symbol_file_add_from_bfd (abfd=..., name=0x55555875d310 "/lib64/ld-linux-x86-64.so.2", add_flags=..., addrs=0x7fffffffd2f0, flags=..., parent=0x0) at src/gdb/symfile.c:1160 #31 0x0000555556546371 in solib_read_symbols (so=..., flags=...) at src/gdb/solib.c:692 #32 0x0000555556546f0f in solib_add (pattern=0x0, from_tty=0, readsyms=1) at src/gdb/solib.c:1015 #33 0x0000555556539891 in enable_break (info=0x55555874e180, from_tty=0) at src/gdb/solib-svr4.c:2416 #34 0x000055555653b305 in svr4_solib_create_inferior_hook (from_tty=0) at src/gdb/solib-svr4.c:3058 #35 0x0000555556547cee in solib_create_inferior_hook (from_tty=0) at src/gdb/solib.c:1217 #36 0x0000555556196f6a in post_create_inferior (from_tty=0) at src/gdb/infcmd.c:275 #37 0x0000555556197670 in run_command_1 (args=0x0, from_tty=1, run_how=RUN_NORMAL) at src/gdb/infcmd.c:486 #38 0x000055555619783f in run_command (args=0x0, from_tty=1) at src/gdb/infcmd.c:512 #39 0x0000555555f0798d in do_simple_func (args=0x0, from_tty=1, c=0x555558567510) at src/gdb/cli/cli-decode.c:95 #40 0x0000555555f0d89a in cmd_func (cmd=0x555558567510, args=0x0, from_tty=1) at src/gdb/cli/cli-decode.c:2735 #41 0x000055555661fb42 in execute_command (p=0x7fffffffe2c4 "", from_tty=1) at src/gdb/top.c:575 #42 0x000055555626303b in catch_command_errors (command=0x55555661f4ab <execute_command(char const*, int)>, arg=0x7fffffffe2c1 "run", from_tty=1, do_bp_actions=true) at src/gdb/main.c:513 #43 0x000055555626328a in execute_cmdargs (cmdarg_vec=0x7fffffffdaf0, file_type=CMDARG_FILE, cmd_type=CMDARG_COMMAND, ret=0x7fffffffda3c) at src/gdb/main.c:612 #44 0x0000555556264849 in captured_main_1 (context=0x7fffffffdd40) at src/gdb/main.c:1293 #45 0x0000555556264a7f in captured_main (data=0x7fffffffdd40) at src/gdb/main.c:1314 #46 0x0000555556264b2e in gdb_main (args=0x7fffffffdd40) at src/gdb/main.c:1343 #47 0x0000555555ceccab in main (argc=9, argv=0x7fffffffde78) at src/gdb/gdb.c:39 (top-gdb) The use of the "target remote" command here is just an example. In principle, we would reproduce the problem with any command that triggers an invocation of `normal_stop`. To omit enabling the stdin in `normal_stop`, we would have to check the context we are in. Since we cannot do that, we add a new field to `struct ui` to track whether the prompt was already blocked, and set the tracker flag in the Python context before executing a GDB command. After applying this patch, the output becomes ... Reading symbols from a.out... Starting program: /tmp/a.out loading /lib64/ld-linux-x86-64.so.2 [New inferior 2] Added inferior 2 [Switching to inferior 2 [<null>] (<noexec>)] stdin/stdout redirected Process /tmp/a.out created; pid = 3032261 Remote debugging using stdio Reading /tmp/a.out from remote target... ... [Switching to inferior 1 [process 3032255] (/tmp/a.out)] [Switching to thread 1.1 (process 3032255)] #0 0x00007ffff7fe3290 in ?? () from /lib64/ld-linux-x86-64.so.2 [Thread debugging using libthread_db enabled] Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1". [Inferior 1 (process 3032255) exited normally] (gdb) Let's now consider a secondary scenario, where the command executed from the Python raises an error. As an example, suppose we have the Python file below: def handle_new_objfile_event(self, event): ... print("loading " + event.new_objfile.filename) self.processed_objfile = True gdb.execute('print a') The executed command, "print a", gives an error because "a" is not defined. Without this patch, we see the behavior below, where the prompt is again placed incorrectly: ... Reading symbols from /tmp/a.out... Starting program: /tmp/a.out loading /lib64/ld-linux-x86-64.so.2 Python Exception <class 'gdb.error'>: No symbol "a" in current context. (gdb) [Inferior 1 (process 3980401) exited normally] This time, `async_enable_stdin` is called from the 'catch' block in `execute_gdb_command`: (top-gdb) bt #0 async_enable_stdin () at src/gdb/event-top.c:523 devkitPro#1 0x0000555556400f0a in execute_gdb_command (self=0x7ffff43b5d00, args=0x7ffff440ab60, kw=0x0) at src/gdb/python/python.c:713 devkitPro#2 0x00007ffff7a96023 in ?? () from /lib/x86_64-linux-gnu/libpython3.10.so.1.0 bminor#3 0x00007ffff7a4dadc in _PyObject_MakeTpCall () from /lib/x86_64-linux-gnu/libpython3.10.so.1.0 bminor#4 0x00007ffff79e9a1c in _PyEval_EvalFrameDefault () from /lib/x86_64-linux-gnu/libpython3.10.so.1.0 bminor#5 0x00007ffff7b303af in ?? () from /lib/x86_64-linux-gnu/libpython3.10.so.1.0 bminor#6 0x00007ffff7a50358 in ?? () from /lib/x86_64-linux-gnu/libpython3.10.so.1.0 bminor#7 0x00007ffff7a4f3f4 in ?? () from /lib/x86_64-linux-gnu/libpython3.10.so.1.0 bminor#8 0x00007ffff7a4f883 in PyObject_CallFunctionObjArgs () from /lib/x86_64-linux-gnu/libpython3.10.so.1.0 bminor#9 0x00005555563a9758 in evpy_emit_event (event=0x7ffff42b5430, registry=0x7ffff42b4690) at src/gdb/python/py-event.c:104 bminor#10 0x00005555563cb874 in emit_new_objfile_event (objfile=0x555558761410) at src/gdb/python/py-newobjfileevent.c:52 bminor#11 0x00005555563b53bc in python_new_objfile (objfile=0x555558761410) at src/gdb/python/py-inferior.c:195 bminor#12 0x0000555555d6dff0 in std::__invoke_impl<void, void (*&)(objfile*), objfile*> (__f=@0x5555585b5860: 0x5555563b5360 <python_new_objfile(objfile*)>) at /usr/include/c++/11/bits/invoke.h:61 #13 0x0000555555d6be18 in std::__invoke_r<void, void (*&)(objfile*), objfile*> (__fn=@0x5555585b5860: 0x5555563b5360 <python_new_objfile(objfile*)>) at /usr/include/c++/11/bits/invoke.h:111 #14 0x0000555555d69661 in std::_Function_handler<void (objfile*), void (*)(objfile*)>::_M_invoke(std::_Any_data const&, objfile*&&) (__functor=..., __args#0=@0x7fffffffd080: 0x555558761410) at /usr/include/c++/11/bits/std_function.h:290 #15 0x0000555556314caf in std::function<void (objfile*)>::operator()(objfile*) const (this=0x5555585b5860, __args#0=0x555558761410) at /usr/include/c++/11/bits/std_function.h:590 #16 0x000055555631444e in gdb::observers::observable<objfile*>::notify (this=0x55555836eea0 <gdb::observers::new_objfile>, args#0=0x555558761410) at src/gdb/../gdbsupport/observable.h:166 #17 0x0000555556599b3f in symbol_file_add_with_addrs (abfd=..., name=0x55555875d020 "/lib64/ld-linux-x86-64.so.2", add_flags=..., addrs=0x7fffffffd2f0, flags=..., parent=0x0) at src/gdb/symfile.c:1125 #18 0x0000555556599ca4 in symbol_file_add_from_bfd (abfd=..., name=0x55555875d020 "/lib64/ld-linux-x86-64.so.2", add_flags=..., addrs=0x7fffffffd2f0, flags=..., parent=0x0) at src/gdb/symfile.c:1160 #19 0x0000555556546371 in solib_read_symbols (so=..., flags=...) at src/gdb/solib.c:692 #20 0x0000555556546f0f in solib_add (pattern=0x0, from_tty=0, readsyms=1) at src/gdb/solib.c:1015 #21 0x0000555556539891 in enable_break (info=0x55555874a670, from_tty=0) at src/gdb/solib-svr4.c:2416 #22 0x000055555653b305 in svr4_solib_create_inferior_hook (from_tty=0) at src/gdb/solib-svr4.c:3058 #23 0x0000555556547cee in solib_create_inferior_hook (from_tty=0) at src/gdb/solib.c:1217 #24 0x0000555556196f6a in post_create_inferior (from_tty=0) at src/gdb/infcmd.c:275 #25 0x0000555556197670 in run_command_1 (args=0x0, from_tty=1, run_how=RUN_NORMAL) at src/gdb/infcmd.c:486 #26 0x000055555619783f in run_command (args=0x0, from_tty=1) at src/gdb/infcmd.c:512 #27 0x0000555555f0798d in do_simple_func (args=0x0, from_tty=1, c=0x555558567510) at src/gdb/cli/cli-decode.c:95 #28 0x0000555555f0d89a in cmd_func (cmd=0x555558567510, args=0x0, from_tty=1) at src/gdb/cli/cli-decode.c:2735 #29 0x000055555661fb42 in execute_command (p=0x7fffffffe2c4 "", from_tty=1) at src/gdb/top.c:575 #30 0x000055555626303b in catch_command_errors (command=0x55555661f4ab <execute_command(char const*, int)>, arg=0x7fffffffe2c1 "run", from_tty=1, do_bp_actions=true) at src/gdb/main.c:513 #31 0x000055555626328a in execute_cmdargs (cmdarg_vec=0x7fffffffdaf0, file_type=CMDARG_FILE, cmd_type=CMDARG_COMMAND, ret=0x7fffffffda3c) at src/gdb/main.c:612 #32 0x0000555556264849 in captured_main_1 (context=0x7fffffffdd40) at src/gdb/main.c:1293 #33 0x0000555556264a7f in captured_main (data=0x7fffffffdd40) at src/gdb/main.c:1314 #34 0x0000555556264b2e in gdb_main (args=0x7fffffffdd40) at src/gdb/main.c:1343 #35 0x0000555555ceccab in main (argc=9, argv=0x7fffffffde78) at src/gdb/gdb.c:39 (top-gdb) Again, after we enable stdin, GDB continues with its normal flow of the 'run' command and receives the inferior's exit event, where it would have enabled stdin, if we had not done it prematurely. (top-gdb) bt #0 async_enable_stdin () at src/gdb/event-top.c:523 devkitPro#1 0x00005555561c3acd in normal_stop () at src/gdb/infrun.c:9432 devkitPro#2 0x00005555561b5bf1 in fetch_inferior_event () at src/gdb/infrun.c:4700 bminor#3 0x000055555618d6a7 in inferior_event_handler (event_type=INF_REG_EVENT) at src/gdb/inf-loop.c:42 bminor#4 0x000055555620ecdb in handle_target_event (error=0, client_data=0x0) at src/gdb/linux-nat.c:4316 bminor#5 0x0000555556f33035 in handle_file_event (file_ptr=0x5555587024e0, ready_mask=1) at src/gdbsupport/event-loop.cc:573 bminor#6 0x0000555556f3362f in gdb_wait_for_event (block=0) at src/gdbsupport/event-loop.cc:694 bminor#7 0x0000555556f322cd in gdb_do_one_event (mstimeout=-1) at src/gdbsupport/event-loop.cc:217 bminor#8 0x0000555556262df8 in start_event_loop () at src/gdb/main.c:407 bminor#9 0x0000555556262f85 in captured_command_loop () at src/gdb/main.c:471 bminor#10 0x0000555556264a84 in captured_main (data=0x7fffffffdd40) at src/gdb/main.c:1324 bminor#11 0x0000555556264b2e in gdb_main (args=0x7fffffffdd40) at src/gdb/main.c:1343 bminor#12 0x0000555555ceccab in main (argc=9, argv=0x7fffffffde78) at src/gdb/gdb.c:39 (top-gdb) The solution implemented by this patch addresses the problem. After applying the patch, the output becomes $ gdb -q -ex "source file.py" -ex "run" --args a.out Reading symbols from /tmp/a.out... Starting program: /tmp/a.out loading /lib64/ld-linux-x86-64.so.2 Python Exception <class 'gdb.error'>: No symbol "a" in current context. [Inferior 1 (process 3984511) exited normally] (gdb) Regression-tested on X86_64 Linux using the default board file (i.e. unix). Co-Authored-By: Oguzhan Karakaya <oguzhan.karakaya@intel.com> Reviewed-By: Guinevere Larsen <blarsen@redhat.com> Approved-By: Tom Tromey <tom@tromey.com>

This commit fixes bug PR 28942, that is, creating a conditional breakpoint in a multi-threaded inferior, where the breakpoint condition includes an inferior function call. Currently, when a user tries to create such a breakpoint, then GDB will fail with: (gdb) break infcall-from-bp-cond-single.c:61 if (return_true ()) Breakpoint 2 at 0x4011fa: file /tmp/build/gdb/testsuite/../../../src/gdb/testsuite/gdb.threads/infcall-from-bp-cond-single.c, line 61. (gdb) continue Continuing. [New Thread 0x7ffff7c5d700 (LWP 2460150)] [New Thread 0x7ffff745c700 (LWP 2460151)] [New Thread 0x7ffff6c5b700 (LWP 2460152)] [New Thread 0x7ffff645a700 (LWP 2460153)] [New Thread 0x7ffff5c59700 (LWP 2460154)] Error in testing breakpoint condition: Couldn't get registers: No such process. An error occurred while in a function called from GDB. Evaluation of the expression containing the function (return_true) will be abandoned. When the function is done executing, GDB will silently stop. Selected thread is running. (gdb) Or, in some cases, like this: (gdb) break infcall-from-bp-cond-simple.c:56 if (is_matching_tid (arg, 1)) Breakpoint 2 at 0x401194: file /tmp/build/gdb/testsuite/../../../src/gdb/testsuite/gdb.threads/infcall-from-bp-cond-simple.c, line 56. (gdb) continue Continuing. [New Thread 0x7ffff7c5d700 (LWP 2461106)] [New Thread 0x7ffff745c700 (LWP 2461107)] ../../src.release/gdb/nat/x86-linux-dregs.c:146: internal-error: x86_linux_update_debug_registers: Assertion `lwp_is_stopped (lwp)' failed. A problem internal to GDB has been detected, further debugging may prove unreliable. The precise error depends on the exact thread state; so there's race conditions depending on which threads have fully started, and which have not. But the underlying problem is always the same; when GDB tries to execute the inferior function call from within the breakpoint condition, GDB will, incorrectly, try to resume threads that are already running - GDB doesn't realise that some threads might already be running. The solution proposed in this patch requires an additional member variable thread_info::in_cond_eval. This flag is set to true (in breakpoint.c) when GDB is evaluating a breakpoint condition. In user_visible_resume_ptid (infrun.c), when the in_cond_eval flag is true, then GDB will only try to resume the current thread, that is, the thread for which the breakpoint condition is being evaluated. This solves the problem of GDB trying to resume threads that are already running. The next problem is that inferior function calls are assumed to be synchronous, that is, GDB doesn't expect to start an inferior function call in thread devkitPro#1, then receive a stop from thread devkitPro#2 for some other, unrelated reason. To prevent GDB responding to an event from another thread, we update fetch_inferior_event and do_target_wait in infrun.c, so that, when an inferior function call (on behalf of a breakpoint condition) is in progress, we only wait for events from the current thread (the one evaluating the condition). In do_target_wait I had to change the inferior_matches lambda function, which is used to select which inferior to wait on. Previously the logic was this: auto inferior_matches = [&wait_ptid] (inferior *inf) { return (inf->process_target () != nullptr && ptid_t (inf->pid).matches (wait_ptid)); }; This compares the pid of the inferior against the complete ptid we want to wait on. Before this commit wait_ptid was only ever minus_one_ptid (which is special, and means any process), and so every inferior would match. After this commit though wait_ptid might represent a specific thread in a specific inferior. If we compare the pid of the inferior to a specific ptid then these will not match. The fix is to compare against the pid extracted from the wait_ptid, not against the complete wait_ptid itself. In fetch_inferior_event, after receiving the event, we only want to stop all the other threads, and call inferior_event_handler with INF_EXEC_COMPLETE, if we are not evaluating a conditional breakpoint. If we are, then all the other threads should be left doing whatever they were before. The inferior_event_handler call will be performed once the breakpoint condition has finished being evaluated, and GDB decides to stop or not. The final problem that needs solving relates to GDB's commit-resume mechanism, which allows GDB to collect resume requests into a single packet in order to reduce traffic to a remote target. The problem is that the commit-resume mechanism will not send any resume requests for an inferior if there are already events pending on the GDB side. Imagine an inferior with two threads. Both threads hit a breakpoint, maybe the same conditional breakpoint. At this point there are two pending events, one for each thread. GDB selects one of the events and spots that this is a conditional breakpoint, GDB evaluates the condition. The condition includes an inferior function call, so GDB sets up for the call and resumes the one thread, the resume request is added to the commit-resume queue. When the commit-resume queue is committed GDB sees that there is a pending event from another thread, and so doesn't send any resume requests to the actual target, GDB is assuming that when we wait we will select the event from the other thread. However, as this is an inferior function call for a condition evaluation, we will not select the event from the other thread, we only care about events from the thread that is evaluating the condition - and the resume for this thread was never sent to the target. And so, GDB hangs, waiting for an event from a thread that was never fully resumed. To fix this issue I have added the concept of "forcing" the commit-resume queue. When enabling commit resume, if the force flag is true, then any resumes will be committed to the target, even if there are other threads with pending events. A note on authorship: this patch was based on some work done by Natalia Saiapova and Tankut Baris Aktemur from Intel[1]. I have made some changes to their work in this version. Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=28942 [1] https://sourceware.org/pipermail/gdb-patches/2020-October/172454.html Co-authored-by: Natalia Saiapova <natalia.saiapova@intel.com> Co-authored-by: Tankut Baris Aktemur <tankut.baris.aktemur@intel.com> Reviewed-By: Tankut Baris Aktemur <tankut.baris.aktemur@intel.com> Tested-By: Luis Machado <luis.machado@arm.com> Tested-By: Keith Seitz <keiths@redhat.com>

…ro linux When running test-case gdb.threads/attach-stopped.exp on aarch64-linux, using the manjaro linux distro, I get: ... (gdb) thread apply all bt^M ^M Thread 2 (Thread 0xffff8d8af120 (LWP 278116) "attach-stopped"):^M #0 0x0000ffff8d964864 in clock_nanosleep () from /usr/lib/libc.so.6^M devkitPro#1 0x0000ffff8d969cac in nanosleep () from /usr/lib/libc.so.6^M devkitPro#2 0x0000ffff8d969b68 in sleep () from /usr/lib/libc.so.6^M bminor#3 0x0000aaaade370828 in func (arg=0x0) at attach-stopped.c:29^M bminor#4 0x0000ffff8d930aec in ?? () from /usr/lib/libc.so.6^M bminor#5 0x0000ffff8d99a5dc in ?? () from /usr/lib/libc.so.6^M ^M Thread 1 (Thread 0xffff8db62020 (LWP 278111) "attach-stopped"):^M #0 0x0000ffff8d92d2d8 in ?? () from /usr/lib/libc.so.6^M devkitPro#1 0x0000ffff8d9324b8 in ?? () from /usr/lib/libc.so.6^M devkitPro#2 0x0000aaaade37086c in main () at attach-stopped.c:45^M (gdb) FAIL: gdb.threads/attach-stopped.exp: threaded: attach2 to stopped bt ... The problem is that the test-case expects to see start_thread: ... gdb_test "thread apply all bt" ".*sleep.*start_thread.*" \ "$threadtype: attach2 to stopped bt" ... but lack of symbols makes that impossible. Fix this by allowing " in ?? () from " as well. Tested on aarch64-linux. PR testsuite/31451 Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=31451

When running test-case gdb.server/connect-with-no-symbol-file.exp on aarch64-linux (specifically, an opensuse leap 15.5 container on a fedora asahi 39 system), I run into: ... (gdb) detach^M Detaching from program: target:connect-with-no-symbol-file, process 185104^M Ending remote debugging.^M terminate called after throwing an instance of 'gdb_exception_error'^M ... The detailed backtrace of the corefile is: ... (gdb) bt #0 0x0000ffff75504f54 in raise () from /lib64/libpthread.so.0 devkitPro#1 0x00000000007a86b4 in handle_fatal_signal (sig=6) at gdb/event-top.c:926 devkitPro#2 <signal handler called> bminor#3 0x0000ffff74b977b4 in raise () from /lib64/libc.so.6 bminor#4 0x0000ffff74b98c18 in abort () from /lib64/libc.so.6 bminor#5 0x0000ffff74ea26f4 in __gnu_cxx::__verbose_terminate_handler() () from /usr/lib64/libstdc++.so.6 bminor#6 0x0000ffff74ea011c in ?? () from /usr/lib64/libstdc++.so.6 bminor#7 0x0000ffff74ea0180 in std::terminate() () from /usr/lib64/libstdc++.so.6 bminor#8 0x0000ffff74ea0464 in __cxa_throw () from /usr/lib64/libstdc++.so.6 bminor#9 0x0000000001548870 in throw_it (reason=RETURN_ERROR, error=TARGET_CLOSE_ERROR, fmt=0x16c7810 "Remote connection closed", ap=...) at gdbsupport/common-exceptions.cc:203 bminor#10 0x0000000001548920 in throw_verror (error=TARGET_CLOSE_ERROR, fmt=0x16c7810 "Remote connection closed", ap=...) at gdbsupport/common-exceptions.cc:211 bminor#11 0x0000000001548a00 in throw_error (error=TARGET_CLOSE_ERROR, fmt=0x16c7810 "Remote connection closed") at gdbsupport/common-exceptions.cc:226 bminor#12 0x0000000000ac8f2c in remote_target::readchar (this=0x233d3d90, timeout=2) at gdb/remote.c:9856 #13 0x0000000000ac9f04 in remote_target::getpkt (this=0x233d3d90, buf=0x233d40a8, forever=false, is_notif=0x0) at gdb/remote.c:10326 #14 0x0000000000acf3d0 in remote_target::remote_hostio_send_command (this=0x233d3d90, command_bytes=13, which_packet=17, remote_errno=0xfffff1a3cf38, attachment=0xfffff1a3ce88, attachment_len=0xfffff1a3ce90) at gdb/remote.c:12567 #15 0x0000000000ad03bc in remote_target::fileio_fstat (this=0x233d3d90, fd=3, st=0xfffff1a3d020, remote_errno=0xfffff1a3cf38) at gdb/remote.c:12979 #16 0x0000000000c39878 in target_fileio_fstat (fd=0, sb=0xfffff1a3d020, target_errno=0xfffff1a3cf38) at gdb/target.c:3315 #17 0x00000000007eee5c in target_fileio_stream::stat (this=0x233d4400, abfd=0x2323fc40, sb=0xfffff1a3d020) at gdb/gdb_bfd.c:467 #18 0x00000000007f012c in <lambda(bfd*, void*, stat*)>::operator()(bfd *, void *, stat *) const (__closure=0x0, abfd=0x2323fc40, stream=0x233d4400, sb=0xfffff1a3d020) at gdb/gdb_bfd.c:955 #19 0x00000000007f015c in <lambda(bfd*, void*, stat*)>::_FUN(bfd *, void *, stat *) () at gdb/gdb_bfd.c:956 #20 0x0000000000f9b838 in opncls_bstat (abfd=0x2323fc40, sb=0xfffff1a3d020) at bfd/opncls.c:665 #21 0x0000000000f90adc in bfd_stat (abfd=0x2323fc40, statbuf=0xfffff1a3d020) at bfd/bfdio.c:431 #22 0x000000000065fe20 in reopen_exec_file () at gdb/corefile.c:52 #23 0x0000000000c3a3e8 in generic_mourn_inferior () at gdb/target.c:3642 #24 0x0000000000abf3f0 in remote_unpush_target (target=0x233d3d90) at gdb/remote.c:6067 #25 0x0000000000aca8b0 in remote_target::mourn_inferior (this=0x233d3d90) at gdb/remote.c:10587 #26 0x0000000000c387cc in target_mourn_inferior ( ptid=<error reading variable: Cannot access memory at address 0x2d310>) at gdb/target.c:2738 #27 0x0000000000abfff0 in remote_target::remote_detach_1 (this=0x233d3d90, inf=0x22fce540, from_tty=1) at gdb/remote.c:6421 #28 0x0000000000ac0094 in remote_target::detach (this=0x233d3d90, inf=0x22fce540, from_tty=1) at gdb/remote.c:6436 #29 0x0000000000c37c3c in target_detach (inf=0x22fce540, from_tty=1) at gdb/target.c:2526 #30 0x0000000000860424 in detach_command (args=0x0, from_tty=1) at gdb/infcmd.c:2817 #31 0x000000000060b594 in do_simple_func (args=0x0, from_tty=1, c=0x231431a0) at gdb/cli/cli-decode.c:94 #32 0x00000000006108c8 in cmd_func (cmd=0x231431a0, args=0x0, from_tty=1) at gdb/cli/cli-decode.c:2741 #33 0x0000000000c65a94 in execute_command (p=0x232e52f6 "", from_tty=1) at gdb/top.c:570 #34 0x00000000007a7d2c in command_handler (command=0x232e52f0 "") at gdb/event-top.c:566 #35 0x00000000007a8290 in command_line_handler (rl=...) at gdb/event-top.c:802 #36 0x0000000000c9092c in tui_command_line_handler (rl=...) at gdb/tui/tui-interp.c:103 #37 0x00000000007a750c in gdb_rl_callback_handler (rl=0x23385330 "detach") at gdb/event-top.c:258 #38 0x0000000000d910f4 in rl_callback_read_char () at readline/readline/callback.c:290 #39 0x00000000007a7338 in gdb_rl_callback_read_char_wrapper_noexcept () at gdb/event-top.c:194 #40 0x00000000007a73f0 in gdb_rl_callback_read_char_wrapper (client_data=0x22fbf640) at gdb/event-top.c:233 #41 0x0000000000cbee1c in stdin_event_handler (error=0, client_data=0x22fbf640) at gdb/ui.c:154 #42 0x000000000154ed60 in handle_file_event (file_ptr=0x232be730, ready_mask=1) at gdbsupport/event-loop.cc:572 #43 0x000000000154f21c in gdb_wait_for_event (block=1) at gdbsupport/event-loop.cc:693 #44 0x000000000154dec4 in gdb_do_one_event (mstimeout=-1) at gdbsupport/event-loop.cc:263 #45 0x0000000000910f98 in start_event_loop () at gdb/main.c:400 #46 0x0000000000911130 in captured_command_loop () at gdb/main.c:464 #47 0x0000000000912b5c in captured_main (data=0xfffff1a3db58) at gdb/main.c:1338 #48 0x0000000000912bf4 in gdb_main (args=0xfffff1a3db58) at gdb/main.c:1357 #49 0x00000000004170f4 in main (argc=10, argv=0xfffff1a3dcc8) at gdb/gdb.c:38 (gdb) ... The abort happens because a c++ exception escapes to c code, specifically opncls_bstat in bfd/opncls.c. Compiling with -fexceptions works around this. Fix this by catching the exception just before it escapes, in stat_trampoline and likewise in few similar spot. Add a new template catch_exceptions to do so in a consistent way. Tested on aarch64-linux. Approved-by: Pedro Alves <pedro@palves.net> PR remote/31577 Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=31577

If threads are disabled, either by --disable-threading explicitely, or by missing std::thread support, you get the following ASAN error when loading symbols: ==7310==ERROR: AddressSanitizer: heap-use-after-free on address 0x614000002128 at pc 0x00000098794a bp 0x7ffe37e6af70 sp 0x7ffe37e6af68 READ of size 1 at 0x614000002128 thread T0 #0 0x987949 in index_cache_store_context::store() const ../../gdb/dwarf2/index-cache.c:163 devkitPro#1 0x943467 in cooked_index_worker::write_to_cache(cooked_index const*, deferred_warnings*) const ../../gdb/dwarf2/cooked-index.c:601 devkitPro#2 0x1705e39 in std::function<void ()>::operator()() const /gcc/9/include/c++/9.2.0/bits/std_function.h:690 bminor#3 0x1705e39 in gdb::task_group::impl::~impl() ../../gdbsupport/task-group.cc:38 0x614000002128 is located 232 bytes inside of 408-byte region [0x614000002040,0x6140000021d8) freed by thread T0 here: #0 0x7fd75ccf8ea5 in operator delete(void*, unsigned long) ../../.././libsanitizer/asan/asan_new_delete.cc:177 devkitPro#1 0x9462e5 in cooked_index::index_for_writing() ../../gdb/dwarf2/cooked-index.h:689 devkitPro#2 0x9462e5 in operator() ../../gdb/dwarf2/cooked-index.c:657 bminor#3 0x9462e5 in _M_invoke /gcc/9/include/c++/9.2.0/bits/std_function.h:300 It's happening because cooked_index_worker::wait always returns true in this case, which tells cooked_index::wait it can delete the m_state cooked_index_worker member, but cooked_index_worker::write_to_cache tries to access it immediately afterwards. Fixed by making cooked_index_worker::wait only return true if desired_state is CACHE_DONE, same as if threading was enabled, so m_state will not be prematurely deleted. Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=31694 Approved-By: Tom Tromey <tom@tromey.com>

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