sessionctx/stmtctx: avoid unlock of unlocked mutex panic on Statement…

…Context

pkg/sessionctx/stmtctx/stmtctx.go

@@ -591,8 +591,9 @@ const (
 
 // GetOrStoreStmtCache gets the cached value of the given key if it exists, otherwise stores the value.
 func (sc *StatementContext) GetOrStoreStmtCache(key StmtCacheKey, value any) any {
-	sc.stmtCache.mu.Lock()
-	defer sc.stmtCache.mu.Unlock()
+	mu := &sc.stmtCache.mu
+	mu.Lock()
+	defer mu.Unlock()
 	if sc.stmtCache.data == nil {
 		sc.stmtCache.data = make(map[StmtCacheKey]any)
 	}
@@ -604,8 +605,9 @@ func (sc *StatementContext) GetOrStoreStmtCache(key StmtCacheKey, value any) any
 
 // GetOrEvaluateStmtCache gets the cached value of the given key if it exists, otherwise calculate the value.
 func (sc *StatementContext) GetOrEvaluateStmtCache(key StmtCacheKey, valueEvaluator func() (any, error)) (any, error) {
-	sc.stmtCache.mu.Lock()
-	defer sc.stmtCache.mu.Unlock()
+	mu := &sc.stmtCache.mu
+	mu.Lock()
+	defer mu.Unlock()
 	if sc.stmtCache.data == nil {
 		sc.stmtCache.data = make(map[StmtCacheKey]any)
 	}
@@ -621,15 +623,17 @@ func (sc *StatementContext) GetOrEvaluateStmtCache(key StmtCacheKey, valueEvalua
 
 // ResetInStmtCache resets the cache of given key.
 func (sc *StatementContext) ResetInStmtCache(key StmtCacheKey) {
-	sc.stmtCache.mu.Lock()
-	defer sc.stmtCache.mu.Unlock()
+	mu := &sc.stmtCache.mu
+	mu.Lock()
+	defer mu.Unlock()
 	delete(sc.stmtCache.data, key)
 }
 
 // ResetStmtCache resets all cached values.
 func (sc *StatementContext) ResetStmtCache() {
-	sc.stmtCache.mu.Lock()
-	defer sc.stmtCache.mu.Unlock()
+	mu := &sc.stmtCache.mu
+	mu.Lock()
+	defer mu.Unlock()
 	sc.stmtCache.data = make(map[StmtCacheKey]any)
 }
 
@@ -798,120 +802,137 @@ func (sc *StatementContext) AddAffectedRows(rows uint64) {
 		// For compatibility with MySQL, not add the affected row cause by the foreign key trigger.
 		return
 	}
-	sc.mu.Lock()
-	defer sc.mu.Unlock()
+	mu := &sc.mu
+	mu.Lock()
+	defer mu.Unlock()
 	sc.mu.affectedRows += rows
 }
 
 // SetAffectedRows sets affected rows.
 func (sc *StatementContext) SetAffectedRows(rows uint64) {
-	sc.mu.Lock()
+	mu := &sc.mu
+	mu.Lock()
+	defer mu.Unlock()
 	sc.mu.affectedRows = rows
-	sc.mu.Unlock()
 }
 
 // AffectedRows gets affected rows.
 func (sc *StatementContext) AffectedRows() uint64 {
-	sc.mu.Lock()
-	defer sc.mu.Unlock()
+	mu := &sc.mu
+	mu.Lock()
+	defer mu.Unlock()
 	return sc.mu.affectedRows
 }
 
 // FoundRows gets found rows.
 func (sc *StatementContext) FoundRows() uint64 {
-	sc.mu.Lock()
-	defer sc.mu.Unlock()
+	mu := &sc.mu
+	mu.Lock()
+	defer mu.Unlock()
 	return sc.mu.foundRows
 }
 
 // AddFoundRows adds found rows.
 func (sc *StatementContext) AddFoundRows(rows uint64) {
-	sc.mu.Lock()
-	defer sc.mu.Unlock()
+	mu := &sc.mu
+	mu.Lock()
+	defer mu.Unlock()
 	sc.mu.foundRows += rows
 }
 
 // RecordRows is used to generate info message
 func (sc *StatementContext) RecordRows() uint64 {
-	sc.mu.Lock()
-	defer sc.mu.Unlock()
+	mu := &sc.mu
+	mu.Lock()
+	defer mu.Unlock()
 	return sc.mu.records
 }
 
 // AddRecordRows adds record rows.
 func (sc *StatementContext) AddRecordRows(rows uint64) {
-	sc.mu.Lock()
-	defer sc.mu.Unlock()
+	mu := &sc.mu
+	mu.Lock()
+	defer mu.Unlock()
 	sc.mu.records += rows
 }
 
 // DeletedRows is used to generate info message
 func (sc *StatementContext) DeletedRows() uint64 {
-	sc.mu.Lock()
-	defer sc.mu.Unlock()
+	mu := &sc.mu
+	mu.Lock()
+	defer mu.Unlock()
 	return sc.mu.deleted
 }
 
 // AddDeletedRows adds record rows.
 func (sc *StatementContext) AddDeletedRows(rows uint64) {
-	sc.mu.Lock()
-	defer sc.mu.Unlock()
+	mu := &sc.mu
+	mu.Lock()
+	defer mu.Unlock()
 	sc.mu.deleted += rows
 }
 
 // UpdatedRows is used to generate info message
 func (sc *StatementContext) UpdatedRows() uint64 {
-	sc.mu.Lock()
-	defer sc.mu.Unlock()
+	mu := &sc.mu
+	mu.Lock()
+	defer mu.Unlock()
 	return sc.mu.updated
 }
 
 // AddUpdatedRows adds updated rows.
 func (sc *StatementContext) AddUpdatedRows(rows uint64) {
-	sc.mu.Lock()
-	defer sc.mu.Unlock()
+	mu := &sc.mu
+	mu.Lock()
+	defer mu.Unlock()
 	sc.mu.updated += rows
 }
 
 // CopiedRows is used to generate info message
 func (sc *StatementContext) CopiedRows() uint64 {
-	sc.mu.Lock()
-	defer sc.mu.Unlock()
+	mu := &sc.mu
+	mu.Lock()
+	defer mu.Unlock()
 	return sc.mu.copied
 }
 
 // AddCopiedRows adds copied rows.
 func (sc *StatementContext) AddCopiedRows(rows uint64) {
-	sc.mu.Lock()
-	defer sc.mu.Unlock()
+	mu := &sc.mu
+	mu.Lock()
+	defer mu.Unlock()
 	sc.mu.copied += rows
 }
 
 // TouchedRows is used to generate info message
 func (sc *StatementContext) TouchedRows() uint64 {
-	sc.mu.Lock()
-	defer sc.mu.Unlock()
+	mu := &sc.mu
+	mu.Lock()
+	defer mu.Unlock()
 	return sc.mu.touched
 }
 
 // AddTouchedRows adds touched rows.
 func (sc *StatementContext) AddTouchedRows(rows uint64) {
-	sc.mu.Lock()
-	defer sc.mu.Unlock()
+	mu := &sc.mu
+	mu.Lock()
+	defer mu.Unlock()
 	sc.mu.touched += rows
 }
 
 // GetMessage returns the extra message of the last executed command, if there is no message, it returns empty string
 func (sc *StatementContext) GetMessage() string {
-	sc.mu.Lock()
-	defer sc.mu.Unlock()
+	mu := &sc.mu
+	mu.Lock()
+	defer mu.Unlock()
 	return sc.mu.message
 }
 
 // SetMessage sets the info message generated by some commands
 func (sc *StatementContext) SetMessage(msg string) {
-	sc.mu.Lock()
-	defer sc.mu.Unlock()
+	mu := &sc.mu
+	mu.Lock()
+	defer mu.Unlock()
 	sc.mu.message = msg
 }
 
@@ -995,8 +1016,9 @@ func (sc *StatementContext) AppendExtraError(warn error) {
 
 // resetMuForRetry resets the changed states of sc.mu during execution.
 func (sc *StatementContext) resetMuForRetry() {
-	sc.mu.Lock()
-	defer sc.mu.Unlock()
+	mu := &sc.mu
+	mu.Lock()
+	defer mu.Unlock()
 	sc.mu.affectedRows = 0
 	sc.mu.foundRows = 0
 	sc.mu.records = 0
@@ -1025,8 +1047,9 @@ func (sc *StatementContext) ResetForRetry() {
 // GetExecDetails gets the execution details for the statement.
 func (sc *StatementContext) GetExecDetails() execdetails.ExecDetails {
 	var details execdetails.ExecDetails
-	sc.mu.Lock()
-	defer sc.mu.Unlock()
+	mu := &sc.mu
+	mu.Lock()
+	defer mu.Unlock()
 	details = sc.SyncExecDetails.GetExecDetails()
 	details.LockKeysDuration = time.Duration(atomic.LoadInt64(&sc.LockKeysDuration))
 	return details