p2p/sentry: sentry doesn't start with ErrNoHead (#10454) (#10523)

cherry-pick #10494 to
release/2.60

cmd/integration/commands/stages.go

@@ -1621,6 +1621,7 @@ func newSync(ctx context.Context, db kv.RwDB, miningConfig *params.MiningConfig,
 		chainConfig,
 		genesisBlock,
 		chainConfig.ChainID.Uint64(),
+		logger,
 	)
 
 	maxBlockBroadcastPeers := func(header *types.Header) uint { return 0 }

eth/backend.go

@@ -573,6 +573,7 @@ func New(ctx context.Context, stack *node.Node, config *ethconfig.Config, logger
 		chainConfig,
 		genesis,
 		backend.config.NetworkID,
+		logger,
 	)
 
 	// limit "new block" broadcasts to at most 10 random peers at time

p2p/sentry/sentry_multi_client/sentry_multi_client.go

@@ -156,9 +156,7 @@ func SentryReconnectAndPumpStreamLoop[TMessage interface{}](
 		statusData, err := statusDataFactory(ctx)
 
 		if err != nil {
-			if !errors.Is(err, sentry.ErrNoHead) {
-				logger.Error("SentryReconnectAndPumpStreamLoop: statusDataFactory error", "stream", streamName, "err", err)
-			}
+			logger.Error("SentryReconnectAndPumpStreamLoop: statusDataFactory error", "stream", streamName, "err", err)
 			time.Sleep(time.Second)
 			continue
 		}

p2p/sentry/status_data_provider.go

@@ -7,6 +7,7 @@ import (
 	"math/big"
 
 	"github.com/holiman/uint256"
+	"github.com/ledgerwatch/log/v3"
 
 	"github.com/ledgerwatch/erigon-lib/chain"
 	libcommon "github.com/ledgerwatch/erigon-lib/common"
@@ -32,27 +33,59 @@ type StatusDataProvider struct {
 
 	networkId   uint64
 	genesisHash libcommon.Hash
+	genesisHead ChainHead
 	heightForks []uint64
 	timeForks   []uint64
+
+	logger log.Logger
 }
 
 func NewStatusDataProvider(
 	db kv.RoDB,
 	chainConfig *chain.Config,
 	genesis *types.Block,
 	networkId uint64,
+	logger log.Logger,
 ) *StatusDataProvider {
 	s := &StatusDataProvider{
 		db:          db,
 		networkId:   networkId,
 		genesisHash: genesis.Hash(),
+		genesisHead: makeGenesisChainHead(genesis),
+		logger:      logger,
 	}
 
 	s.heightForks, s.timeForks = forkid.GatherForks(chainConfig, genesis.Time())
 
 	return s
 }
 
+func uint256FromBigInt(num *big.Int) (*uint256.Int, error) {
+	if num == nil {
+		num = new(big.Int)
+	}
+	num256 := new(uint256.Int)
+	overflow := num256.SetFromBig(num)
+	if overflow {
+		return nil, fmt.Errorf("uint256FromBigInt: big.Int greater than 2^256-1")
+	}
+	return num256, nil
+}
+
+func makeGenesisChainHead(genesis *types.Block) ChainHead {
+	genesisDifficulty, err := uint256FromBigInt(genesis.Difficulty())
+	if err != nil {
+		panic(fmt.Errorf("makeGenesisChainHead: difficulty conversion error: %w", err))
+	}
+
+	return ChainHead{
+		HeadHeight: genesis.NumberU64(),
+		HeadTime:   genesis.Time(),
+		HeadHash:   genesis.Hash(),
+		HeadTd:     genesisDifficulty,
+	}
+}
+
 func (s *StatusDataProvider) makeStatusData(head ChainHead) *proto_sentry.StatusData {
 	return &proto_sentry.StatusData{
 		NetworkId:       s.networkId,
@@ -71,6 +104,10 @@ func (s *StatusDataProvider) makeStatusData(head ChainHead) *proto_sentry.Status
 func (s *StatusDataProvider) GetStatusData(ctx context.Context) (*proto_sentry.StatusData, error) {
 	chainHead, err := ReadChainHead(ctx, s.db)
 	if err != nil {
+		if errors.Is(err, ErrNoHead) {
+			s.logger.Warn("sentry.StatusDataProvider: The canonical chain current header not found in the database. Check the database consistency. Using genesis as a fallback.")
+			return s.makeStatusData(s.genesisHead), nil
+		}
 		return nil, err
 	}
 	return s.makeStatusData(chainHead), err
@@ -84,23 +121,15 @@ func ReadChainHeadWithTx(tx kv.Tx) (ChainHead, error) {
 
 	height := header.Number.Uint64()
 	hash := header.Hash()
-
-	var time uint64
-	if header != nil {
-		time = header.Time
-	}
+	time := header.Time
 
 	td, err := rawdb.ReadTd(tx, hash, height)
 	if err != nil {
 		return ChainHead{}, fmt.Errorf("ReadChainHead: ReadTd error at height %d and hash %s: %w", height, hash, err)
 	}
-	if td == nil {
-		td = new(big.Int)
-	}
-	td256 := new(uint256.Int)
-	overflow := td256.SetFromBig(td)
-	if overflow {
-		return ChainHead{}, fmt.Errorf("ReadChainHead: total difficulty higher than 2^256-1")
+	td256, err := uint256FromBigInt(td)
+	if err != nil {
+		return ChainHead{}, fmt.Errorf("ReadChainHead: total difficulty conversion error: %w", err)
 	}
 
 	return ChainHead{height, time, hash, td256}, nil

turbo/stages/mock/mock_sentry.go

@@ -371,6 +371,7 @@ func MockWithEverything(tb testing.TB, gspec *types.Genesis, key *ecdsa.PrivateK
 		mock.ChainConfig,
 		mock.Genesis,
 		mock.ChainConfig.ChainID.Uint64(),
+		logger,
 	)
 
 	maxBlockBroadcastPeers := func(header *types.Header) uint { return 0 }