go runtime_error ai_generated true

fatal error: sync: RUnlock of unlocked RWMutex

ID: go/fatal-error-sync-runlock-of-unlocked-rwmutex

Also available as: JSON · Markdown · 中文
80%Fix Rate
88%Confidence
0Evidence
2024-08-11First Seen

Version Compatibility

VersionStatusIntroducedDeprecatedNotes
1.18 active — — —
1.22 active — — —

Root Cause

RUnlock() is called without a matching RLock(), or the read lock was already released, corrupting the reader count.

generic

中文

在没有匹配 RLock() 的情况下调用 RUnlock()，或读锁已被释放，破坏了读者计数。

Workarounds

  1. 94% success 
    Pair defer mu.RUnlock() with mu.RLock() on the next line, and defer mu.Unlock() with mu.Lock(), never mixing them.
  2. 90% success 
    Use a helper: func withReadLock(mu *sync.RWMutex, fn func()) { mu.RLock(); defer mu.RUnlock(); fn() }.

Dead Ends

Common approaches that don't work:

  1. 70% fail

    This sacrifices read concurrency and does not fix the missing RLock; if RUnlock is still called, it now mismatches Lock/Unlock.

  2. 90% fail

    Adds an extra lock that is never released, causing a permanent deadlock on the next writer.