1 // run 2 3 // Copyright 2015 The Go Authors. All rights reserved. 4 // Use of this source code is governed by a BSD-style 5 // license that can be found in the LICENSE file. 6 7 // Test that stack barriers are reset when a goroutine exits without 8 // returning. 9 10 package main 11 12 import ( 13 "runtime" 14 "sync/atomic" 15 "time" 16 ) 17 18 func main() { 19 // Let the garbage collector run concurrently. 20 runtime.GOMAXPROCS(2) 21 22 var x [100][]byte 23 24 for i := range x { 25 var done int32 26 27 go func() { 28 // Use enough stack to get stack barriers, but 29 // not so much that we go over _FixedStack. 30 // There's a very narrow window here on most 31 // OSs, so we basically can't do anything (not 32 // even a time.Sleep or a channel). 33 var buf [1024]byte 34 buf[0]++ 35 for atomic.LoadInt32(&done) == 0 { 36 runtime.Gosched() 37 } 38 atomic.StoreInt32(&done, 0) 39 // Exit without unwinding stack barriers. 40 runtime.Goexit() 41 }() 42 43 // Generate some garbage. 44 x[i] = make([]byte, 1024*1024) 45 46 // Give GC some time to install stack barriers in the G. 47 time.Sleep(50 * time.Microsecond) 48 atomic.StoreInt32(&done, 1) 49 for atomic.LoadInt32(&done) == 1 { 50 runtime.Gosched() 51 } 52 } 53 } 54
