有哪位高手帮我看看这段代码有什么问题

```go package main import "fmt" import "sync" func main(){ var wg sync.WaitGroup wg.Add(1) f(wg) wg.Wait() fmt.Println("exit from main") } func f(wg sync.WaitGroup){ defer func(){ if e := recover(); e != nil { fmt.Println("caught panic") } wg.Done() }() go func(){ defer func(){ if e := recover(); e != nil { fmt.Println(e) } }() panic(1) }() } ``` 执行结果： ``` 1 fatal error: all goroutines are asleep - deadlock! goroutine 1 [semacquire]: sync.runtime_Semacquire(0xc42000e23c) /home/zenglin/Downloads/go1.8/src/runtime/sema.go:47 +0x34 sync.(*WaitGroup).Wait(0xc42000e230) /home/zenglin/Downloads/go1.8/src/sync/waitgroup.go:131 +0x7a main.main() /mnt/hgfs/src/test/test.go:10 +0x6c exit status 2 ``` 怎么会所有的协程都阻塞？