fix: check kill signal against 0

config/retry/backoff.go

@@ -218,7 +218,12 @@ func (b *Backoffer) BackoffWithCfgAndMaxSleep(cfg *Config, maxSleepMs int, err e
 	}
 
 	if b.vars != nil && b.vars.Killed != nil {
-		if atomic.LoadUint32(b.vars.Killed) == 1 {
+		killed := atomic.LoadUint32(b.vars.Killed)
+		if killed != 0 {
+			logutil.BgLogger().Info(
+				"backoff stops because a killed signal is received",
+				zap.Uint32("signal", killed),
+			)
 			return errors.WithStack(tikverr.ErrQueryInterrupted)
 		}
 	}

integration_tests/2pc_test.go

@@ -2502,3 +2502,13 @@ func (s *testCommitterSuite) TestExtractKeyExistsErr() {
 	s.True(txn.GetMemBuffer().TryLock())
 	txn.GetMemBuffer().Unlock()
 }
+
+func (s *testCommitterSuite) TestKillSignal() {
+	txn := s.begin()
+	err := txn.Set([]byte("key"), []byte("value"))
+	s.Nil(err)
+	var killed uint32 = 2
+	txn.SetVars(kv.NewVariables(&killed))
+	err = txn.Commit(context.Background())
+	s.ErrorContains(err, "query interrupted")
+}

internal/client/retry/backoff.go

@@ -218,7 +218,12 @@ func (b *Backoffer) BackoffWithCfgAndMaxSleep(cfg *Config, maxSleepMs int, err e
 	}
 
 	if b.vars != nil && b.vars.Killed != nil {
-		if atomic.LoadUint32(b.vars.Killed) == 1 {
+		killed := atomic.LoadUint32(b.vars.Killed)
+		if killed != 0 {
+			logutil.BgLogger().Info(
+				"backoff stops because a killed signal is received",
+				zap.Uint32("signal", killed),
+			)
 			return errors.WithStack(tikverr.ErrQueryInterrupted)
 		}
 	}

internal/locate/region_request.go

@@ -1478,8 +1478,15 @@ func (s *RegionRequestSender) SendReqCtx(
 
 		// recheck whether the session/query is killed during the Next()
 		boVars := bo.GetVars()
-		if boVars != nil && boVars.Killed != nil && atomic.LoadUint32(boVars.Killed) == 1 {
-			return nil, nil, retryTimes, errors.WithStack(tikverr.ErrQueryInterrupted)
+		if boVars != nil && boVars.Killed != nil {
+			killed := atomic.LoadUint32(boVars.Killed)
+			if killed != 0 {
+				logutil.BgLogger().Info(
+					"backoff stops because a killed signal is received",
+					zap.Uint32("signal", killed),
+				)
+				return nil, nil, retryTimes, errors.WithStack(tikverr.ErrQueryInterrupted)
+			}
 		}
 		if val, err := util.EvalFailpoint("mockRetrySendReqToRegion"); err == nil {
 			if val.(bool) {

kv/variables.go

@@ -44,6 +44,10 @@ type Variables struct {
 
 	// Pointer to SessionVars.Killed
 	// Killed is a flag to indicate that this query is killed.
+	// This is an enum value rather than a boolean. See sqlkiller.go
+	// in TiDB for its definition.
+	// When its value is 0, it's not killed
+	// When its value is not 0, it's killed, the value indicates concrete reason.
 	Killed *uint32
 }