go runtime_error ai_generated true

WARNING: DATA RACE: Write by goroutine X, Read by goroutine Y (sync.Pool)

ID: go/goroutine-sync-pool-race

Also available as: JSON · Markdown · 中文
80%Fix Rate
83%Confidence
0Evidence
2025-09-10First Seen

Version Compatibility

VersionStatusIntroducedDeprecatedNotes
1.3 active — — —
1.20 active — — —

Root Cause

Using sync.Pool without proper understanding; objects in pool may be accessed concurrently without synchronization.

generic

中文

未正确理解sync.Pool的使用；池中的对象可能在没有同步的情况下被并发访问。

Workarounds

  1. 85% success Ensure pooled objects are not shared between goroutines 
    pool := &sync.Pool{New: func() interface{} { return &MyStruct{} }}
go func() {
    obj := pool.Get().(*MyStruct)
    // use obj exclusively
    pool.Put(obj)
}()
  2. 80% success Use mutex inside pooled object if sharing is needed 
    type MyStruct struct {
    mu sync.Mutex
    data int
}
obj := pool.Get().(*MyStruct)
obj.mu.Lock()
obj.data = 42
obj.mu.Unlock()
pool.Put(obj)

Dead Ends

Common approaches that don't work:

  1. Assuming sync.Pool provides synchronization 90% fail

    sync.Pool does not synchronize access to pooled objects; only the pool itself is safe.

  2. Using global variables instead of pool 80% fail

    Global variables are shared; race condition persists.