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authorIan Lance Taylor <iant@golang.org>2010-06-30 13:14:46 -0700
committerIan Lance Taylor <iant@golang.org>2010-06-30 13:14:46 -0700
commitd364bb8ed786ab6c4877f19f0b286ed05894f0b0 (patch)
tree6d971ec4784d9c080bec2fc01c9cf132750705c6 /src
parent84cdef467e565d5fa3e43cc7b4307211cb17af30 (diff)
downloadgolang-d364bb8ed786ab6c4877f19f0b286ed05894f0b0.tar.gz
io: Avoid race condition in pipe.
One goroutine started up and was waiting in rw. Then another goroutine decided to close the pipe. The closing goroutine stalled calling p.io.Lock() in pipeHalf.close. (This happened in gccgo). If the closing goroutine had been able to set the ioclosed flag, it would have gone on to tell the runner that the pipe was closed, which would then send an EINVAL to the goroutine sleeping in rw. Unlocking p.io before sleeping in rw avoids the race. R=rsc, rsc1 CC=golang-dev http://codereview.appspot.com/1682048
Diffstat (limited to 'src')
-rw-r--r--src/pkg/io/pipe.go3
1 files changed, 2 insertions, 1 deletions
diff --git a/src/pkg/io/pipe.go b/src/pkg/io/pipe.go
index 79221bd49..898526921 100644
--- a/src/pkg/io/pipe.go
+++ b/src/pkg/io/pipe.go
@@ -144,10 +144,11 @@ func (p *pipeHalf) rw(data []byte) (n int, err os.Error) {
// Run i/o operation.
// Check ioclosed flag under lock to make sure we're still allowed to do i/o.
p.io.Lock()
- defer p.io.Unlock()
if p.ioclosed {
+ p.io.Unlock()
return 0, os.EINVAL
}
+ p.io.Unlock()
p.c1 <- data
res := <-p.c2
return res.n, res.err