go concurrency_error ai_generated true

goroutine leak detected

ID: go/goroutine-leak

Also available as: JSON · Markdown
85%Fix Rate
88%Confidence
50Evidence
2023-01-01First Seen

Version Compatibility

VersionStatusIntroducedDeprecatedNotes
121 active — — —
1 active — — —

Root Cause

Goroutines are not being cleaned up, usually from missing context cancellation or blocked channel operations.

generic

Workarounds

  1. 92% success Add select with context.Done() to every goroutine for cancellation 
    go func(ctx context.Context) {
  for {
    select {
    case <-ctx.Done():
      return
    case msg := <-ch:
      process(msg)
    }
  }
}(ctx)

    Sources: https://pkg.go.dev/context

  2. 90% success Use errgroup for managing goroutine lifecycles 
    g, ctx := errgroup.WithContext(ctx)
for _, item := range items {
  item := item
  g.Go(func() error {
    return process(ctx, item)
  })
}
if err := g.Wait(); err != nil {
  log.Fatal(err)
}

    Sources: https://pkg.go.dev/golang.org/x/sync/errgroup

  3. 85% success Monitor goroutine count with runtime.NumGoroutine() in tests 
    func TestNoLeak(t *testing.T) {
  before := runtime.NumGoroutine()
  doWork()
  time.Sleep(100 * time.Millisecond)
  after := runtime.NumGoroutine()
  if after > before+1 {
    t.Errorf("goroutine leak: before=%d after=%d", before, after)
  }
}

    Sources: https://pkg.go.dev/runtime#NumGoroutine

Dead Ends

Common approaches that don't work:

  1. Increase GOMAXPROCS to handle more goroutines 80% fail

    GOMAXPROCS controls OS thread count, not goroutine count; leaked goroutines still consume memory

  2. Use runtime.Goexit() to kill goroutines 85% fail

    Goexit only terminates the calling goroutine; cannot kill other goroutines externally

Error Chain

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Preceded by: