Always run rustc in a thread #56813

oli-obk · 2018-12-14T12:12:36Z

Previously we moved to only producing threads when absolutely necessary. Even before we opted to only create threads in some cases, which is unsound due to the way we use thread local storage.

ishitatsuyuki · 2018-12-14T15:52:38Z

Please remove std::rt::update_stack_guard in the case, since we won't be maintaining that functionality.

nagisa · 2018-12-15T09:38:08Z

src/librustc_driver/lib.rs

-    if spawn_thread || env::var_os("RUST_MIN_STACK").is_some() {
+    // We need a thread for soundness of thread local storage in rustc. For debugging purposes
+    // we allow an escape hatch where everything runs on the main thread.
+    if env::var_os("RUSTC_UNSTABLE_NO_MAIN_THREAD").is_none() {


I find the idea of using an environment variable here so undiscoverable that the condition might as well be false for all intents and purposes…

The manual page for rustc technically has a section on environment variables. Perhaps it would be a good place to document this envvar there as well?

Also, does the compiler have a part of its --help -v output dedicated to environment variables? That might be nice too.

(having said that, such additions can wait for a followup PR... lets get this PR in now.)

cc #45495 (and maybe #44074?)

This env var is gone now that #56732 landed.

nagisa · 2018-12-15T09:38:19Z

The implementation looks good to me.

pnkfelix · 2018-12-17T12:50:06Z

@bors r+

bors · 2018-12-17T12:50:07Z

📌 Commit 6b96827 has been approved by pnkfelix

bors · 2018-12-20T17:04:20Z

⌛ Testing commit 6b96827 with merge 890597e8a9d43fec4b2ee71809d27822cb6b4f17...

bors · 2018-12-20T18:46:07Z

💔 Test failed - status-travis

rust-highfive · 2018-12-20T18:46:09Z

The job dist-x86_64-linux of your PR failed on Travis (raw log). Through arcane magic we have determined that the following fragments from the build log may contain information about the problem.

Click to expand the log.

[01:36:29]    Compiling cargo v0.32.0
[01:36:35] error[E0308]: mismatched types
[01:36:35]  --> /cargo/registry/src/github.com-1ecc6299db9ec823/cargo-0.32.0/src/cargo/util/sha256.rs:9:34
[01:36:35]   |
[01:36:35] 9 |         let hasher = Hasher::new(Algorithm::SHA256);
[01:36:35]   |                                  |
[01:36:35]   |                                  |
[01:36:35]   |                                  expected reference, found enum `util::sha256::crypto_hash::Algorithm`
[01:36:35]   |                                  help: consider borrowing here: `&Algorithm::SHA256`
[01:36:35]   |
[01:36:35]   = note: expected type `&util::sha256::crypto_hash::Algorithm`
[01:36:35]              found type `util::sha256::crypto_hash::Algorithm`
[01:36:35] error: aborting due to previous error
[01:36:35] 
[01:36:35] For more information about this error, try `rustc --explain E0308`.
[01:36:35] For more information about this error, try `rustc --explain E0308`.
[01:36:35] error: failed to compile `cargo-vendor v0.1.22`, intermediate artifacts can be found at `/checkout/obj/build/x86_64-unknown-linux-gnu/stage0-bootstrap-tools`
[01:36:35] Caused by:
[01:36:35]   Could not compile `cargo`.
[01:36:35] 
[01:36:35] To learn more, run the command again with --verbose.
[01:36:35] To learn more, run the command again with --verbose.
[01:36:35] 
[01:36:35] 
[01:36:35] command did not execute successfully: "/checkout/obj/build/x86_64-unknown-linux-gnu/stage0/bin/cargo" "install" "-j" "4" "--locked" "--color" "always" "--force" "--debug" "--vers" "0.1.22" "cargo-vendor"
[01:36:35] 
[01:36:35] 
[01:36:35] failed to run: /checkout/obj/build/bootstrap/debug/bootstrap dist --host x86_64-unknown-linux-gnu --target x86_64-unknown-linux-gnu
[01:36:35] Build completed unsuccessfully in 1:30:43
---
travis_time:end:0fd00d0c:start=1545331532947154253,finish=1545331532959197945,duration=12043692
travis_fold:end:after_failure.3
travis_fold:start:after_failure.4
travis_time:start:05e5c405
$ ln -s . checkout && for CORE in obj/cores/core.*; do EXE=$(echo $CORE | sed 's|obj/cores/core\.[0-9]*\.!checkout!\(.*\)|\1|;y|!|/|'); if [ -f "$EXE" ]; then printf travis_fold":start:crashlog\n\033[31;1m%s\033[0m\n" "$CORE"; gdb --batch -q -c "$CORE" "$EXE" -iex 'set auto-load off' -iex 'dir src/' -iex 'set sysroot .' -ex bt -ex q; echo travis_fold":"end:crashlog; fi; done || true
travis_fold:end:after_failure.4
travis_fold:start:after_failure.5
travis_time:start:0eb80e5e
travis_time:start:0eb80e5e
$ cat ./obj/build/x86_64-unknown-linux-gnu/native/asan/build/lib/asan/clang_rt.asan-dynamic-i386.vers || true
cat: ./obj/build/x86_64-unknown-linux-gnu/native/asan/build/lib/asan/clang_rt.asan-dynamic-i386.vers: No such file or directory
travis_fold:end:after_failure.5
travis_fold:start:after_failure.6
travis_time:start:0df16a48
$ dmesg | grep -i kill

I'm a bot! I can only do what humans tell me to, so if this was not helpful or you have suggestions for improvements, please ping or otherwise contact @TimNN. (Feature Requests)

alexcrichton · 2018-12-20T19:29:27Z

@bors: retry

0.3.2 contains a breaking change malept/crypto-hash#6

bors · 2018-12-21T10:46:23Z

⌛ Testing commit 6b96827 with merge 01c6ea2...

@ishitatsuyuki

Always run rustc in a thread cc @ishitatsuyuki @eddyb r? @pnkfelix [Previously](#48575) we moved to only producing threads when absolutely necessary. Even before we opted to only create threads in some cases, which [is unsound](#48575 (comment)) due to the way we use thread local storage.

bors · 2018-12-21T13:35:17Z

☀️ Test successful - status-appveyor, status-travis
Approved by: pnkfelix
Pushing 01c6ea2 to master...

nikomatsakis · 2019-01-10T15:48:32Z

In the @rust-lang/compiler meeting today, we decided against backporting this because the problem just doesn't seem that urgent. The bug is in stable already and not many folks have commented on it (it's quite challenging to reproduce). So it can ride the trains as usual, lower risk. (discussion)

Always run rustc in a thread

4dfb91d

rust-highfive assigned pnkfelix Dec 14, 2018

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oli-obk force-pushed the main_ branch from e658c9b to 88ec87f Compare December 14, 2018 17:18

Remove dead code

6b96827

oli-obk force-pushed the main_ branch from 88ec87f to 6b96827 Compare December 14, 2018 17:35

nagisa reviewed Dec 15, 2018

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bors added S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Dec 17, 2018

oli-obk mentioned this pull request Dec 20, 2018

regression: stack overflow on macosx with xcode 6.4 #55471

Closed

bors added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. and removed S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. labels Dec 20, 2018

bors added S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Dec 20, 2018

bors merged commit 6b96827 into rust-lang:master Dec 21, 2018

bors mentioned this pull request Dec 21, 2018

Various cosmetic and minor changes #57016

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pietroalbini added the beta-nominated Nominated for backporting to the compiler in the beta channel. label Jan 9, 2019

nikomatsakis removed the beta-nominated Nominated for backporting to the compiler in the beta channel. label Jan 10, 2019

This was referenced Sep 23, 2019

Upgrading to Rust 1.27.0 fails on Mac OS 10.10 with Homebrew #51838

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'solaris' runtime stack guard conflicts with OS stack-clash mitigation #52577

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Always run rustc in a thread #56813

Always run rustc in a thread #56813

oli-obk commented Dec 14, 2018 •

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Always run rustc in a thread #56813

Always run rustc in a thread #56813

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