go runtime_error ai_generated true

fatal error: all goroutines are asleep - deadlock! (circular wait)

ID: go/deadlock-with-multiple-channels

Also available as: JSON · Markdown · 中文
80%Fix Rate
82%Confidence
0Evidence
2024-09-01First Seen

Version Compatibility

VersionStatusIntroducedDeprecatedNotes
1.20 active — — —
1.21 active — — —

Root Cause

Multiple goroutines are waiting on each other's channels, forming a circular dependency that cannot be resolved.

generic

中文

多个 goroutine 在相互等待对方的通道，形成无法解决的循环依赖。

Workarounds

  1. 85% success 
    select {
case v := <-ch1:
    fmt.Println(v)
case <-time.After(time.Second):
    fmt.Println("timeout")
}
  2. 90% success 
    type Coordinator struct {
    ch chan int
}

func (c *Coordinator) Run() {
    for v := range c.ch {
        go func(v int) {
            // process
        }(v)
    }
}

Dead Ends

Common approaches that don't work:

  1. 80% fail

    Buffering only delays the deadlock; it doesn't break the circular wait.

  2. 90% fail

    Sleeping doesn't guarantee the order; the race condition remains.