diff options
| author | Ian Lance Taylor <iant@golang.org> | 2016-07-07 17:43:08 -0700 |
|---|---|---|
| committer | Andrew Gerrand <adg@golang.org> | 2016-07-08 02:05:40 +0000 |
| commit | 84bb9e62f06dbb62279241fa0bd7a6c8846271ac (patch) | |
| tree | 6529e2381816c0789f1c06a0cf2899ddf37ffacd /src/runtime/stack.go | |
| parent | e5ff529679b3adbed06d509b0fc21a76b62e89e9 (diff) | |
| download | go-84bb9e62f06dbb62279241fa0bd7a6c8846271ac.tar.xz | |
runtime: handle selects with duplicate channels in shrinkstack
The shrinkstack code locks all the channels a goroutine is waiting for,
but didn't handle the case of the same channel appearing in the list
multiple times. This led to a deadlock. The channels are sorted so it's
easy to avoid locking the same channel twice.
Fixes #16286.
Change-Id: Ie514805d0532f61c942e85af5b7b8ac405e2ff65
Reviewed-on: https://go-review.googlesource.com/24815
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
Diffstat (limited to 'src/runtime/stack.go')
| -rw-r--r-- | src/runtime/stack.go | 12 |
1 files changed, 10 insertions, 2 deletions
diff --git a/src/runtime/stack.go b/src/runtime/stack.go index b14b4005d8..8398a101fd 100644 --- a/src/runtime/stack.go +++ b/src/runtime/stack.go @@ -784,8 +784,12 @@ func syncadjustsudogs(gp *g, used uintptr, adjinfo *adjustinfo) uintptr { // copystack; otherwise, gp may be in the middle of // putting itself on wait queues and this would // self-deadlock. + var lastc *hchan for sg := gp.waiting; sg != nil; sg = sg.waitlink { - lock(&sg.c.lock) + if sg.c != lastc { + lock(&sg.c.lock) + } + lastc = sg.c } // Adjust sudogs. @@ -803,8 +807,12 @@ func syncadjustsudogs(gp *g, used uintptr, adjinfo *adjustinfo) uintptr { } // Unlock channels. + lastc = nil for sg := gp.waiting; sg != nil; sg = sg.waitlink { - unlock(&sg.c.lock) + if sg.c != lastc { + unlock(&sg.c.lock) + } + lastc = sg.c } return sgsize |