diff --git a/config/retry/backoff.go b/config/retry/backoff.go
index 6122e300d6..a2723e05b3 100644
--- a/config/retry/backoff.go
+++ b/config/retry/backoff.go
@@ -217,9 +217,10 @@ func (b *Backoffer) BackoffWithCfgAndMaxSleep(cfg *Config, maxSleepMs int, err e
 		atomic.AddInt64(&detail.BackoffCount, 1)
 	}
 
-	err2 := b.CheckKilled()
-	if err2 != nil {
-		return err2
+	if b.vars != nil && b.vars.Killed != nil {
+		if atomic.LoadUint32(b.vars.Killed) == 1 {
+			return errors.WithStack(tikverr.ErrQueryInterrupted)
+		}
 	}
 
 	var startTs interface{}
@@ -381,17 +382,3 @@ func (b *Backoffer) longestSleepCfg() (*Config, int) {
 	}
 	return nil, 0
 }
-
-func (b *Backoffer) CheckKilled() error {
-	if b.vars != nil && b.vars.Killed != nil {
-		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)
-		}
-	}
-	return nil
-}
diff --git a/integration_tests/2pc_test.go b/integration_tests/2pc_test.go
index 9369bfb666..355dafeae1 100644
--- a/integration_tests/2pc_test.go
+++ b/integration_tests/2pc_test.go
@@ -2502,13 +2502,3 @@ 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")
-}
diff --git a/internal/client/retry/backoff.go b/internal/client/retry/backoff.go
index 7a35a74b6d..a2723e05b3 100644
--- a/internal/client/retry/backoff.go
+++ b/internal/client/retry/backoff.go
@@ -217,38 +217,23 @@ func (b *Backoffer) BackoffWithCfgAndMaxSleep(cfg *Config, maxSleepMs int, err e
 		atomic.AddInt64(&detail.BackoffCount, 1)
 	}
 
-	err2 := b.checkKilled()
-	if err2 != nil {
-		return err2
+	if b.vars != nil && b.vars.Killed != nil {
+		if atomic.LoadUint32(b.vars.Killed) == 1 {
+			return errors.WithStack(tikverr.ErrQueryInterrupted)
+		}
 	}
 
 	var startTs interface{}
 	if ts := b.ctx.Value(TxnStartKey); ts != nil {
 		startTs = ts
 	}
-	logutil.Logger(b.ctx).Debug(
-		"retry later",
+	logutil.Logger(b.ctx).Debug("retry later",
 		zap.Error(err),
 		zap.Int("totalSleep", b.totalSleep),
 		zap.Int("excludedSleep", b.excludedSleep),
 		zap.Int("maxSleep", b.maxSleep),
 		zap.Stringer("type", cfg),
-		zap.Reflect("txnStartTS", startTs),
-	)
-	return nil
-}
-
-func (b *Backoffer) checkKilled() error {
-	if b.vars != nil && b.vars.Killed != nil {
-		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)
-		}
-	}
+		zap.Reflect("txnStartTS", startTs))
 	return nil
 }
 
diff --git a/internal/locate/region_request.go b/internal/locate/region_request.go
index 4ddd13160d..b5638eefce 100644
--- a/internal/locate/region_request.go
+++ b/internal/locate/region_request.go
@@ -1498,8 +1498,9 @@ func (s *RegionRequestSender) SendReqCtx(
 		}
 
 		// recheck whether the session/query is killed during the Next()
-		if err2 := bo.CheckKilled(); err2 != nil {
-			return nil, nil, retryTimes, err2
+		boVars := bo.GetVars()
+		if boVars != nil && boVars.Killed != nil && atomic.LoadUint32(boVars.Killed) == 1 {
+			return nil, nil, retryTimes, errors.WithStack(tikverr.ErrQueryInterrupted)
 		}
 		if val, err := util.EvalFailpoint("mockRetrySendReqToRegion"); err == nil {
 			if val.(bool) {
diff --git a/kv/variables.go b/kv/variables.go
index cae78c9c59..581be54d04 100644
--- a/kv/variables.go
+++ b/kv/variables.go
@@ -44,10 +44,6 @@ 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
 }