go runtime_error ai_generated true

fatal error: sync: unlock of unlocked mutex

ID: go/mutex-unlock-of-unlocked

Also available as: JSON · Markdown · 中文
80%Fix Rate
90%Confidence
0Evidence
2024-06-18First Seen

Version Compatibility

VersionStatusIntroducedDeprecatedNotes
1.x active — — —

Root Cause

Unlock() is called on a sync.Mutex that is not currently locked by this goroutine. Often caused by double Unlock, or Unlock in a defer that runs after an early return path already unlocked.

generic

中文

对当前未由本 goroutine 锁定的 sync.Mutex 调用 Unlock()。常由重复 Unlock 引起，或 defer 中的 Unlock 在提前返回路径已解锁后再次执行。

Workarounds

  1. 95% success 
    Use defer mu.Unlock() immediately after a single mu.Lock() and never unlock elsewhere:
mu.Lock()
defer mu.Unlock()
// critical section
  2. 85% success 
    Encapsulate lock/unlock in a helper that tracks state, or restructure so the lock scope matches the function scope exactly.

Dead Ends

Common approaches that don't work:

  1. 95% fail

    This is a fatal runtime error, not a recoverable panic; recover does not catch it.

  2. 70% fail

    Increases risk of forgetting to unlock on error paths, causing deadlocks instead.