diff options
| author | Dmitriy Vyukov <dvyukov@google.com> | 2014-08-21 11:46:53 +0400 |
|---|---|---|
| committer | Dmitriy Vyukov <dvyukov@google.com> | 2014-08-21 11:46:53 +0400 |
| commit | a0dbbeae6785ed7fd15feb4feb4975eded83c191 (patch) | |
| tree | 8018db3784aac053b54d88d9259108280d41f28a /src/pkg/runtime/proc.c | |
| parent | e249b0ffeeb36957adfde2b3ec3ab0eabea8e3ba (diff) | |
| download | go-a0dbbeae6785ed7fd15feb4feb4975eded83c191.tar.xz | |
runtime: fix deadlock when gctrace
Calling ReadMemStats which does stoptheworld on m0 holding locks
was not a good idea.
Stoptheworld holding locks is a recipe for deadlocks (added check for this).
Stoptheworld on g0 may or may not work (added check for this as well).
As far as I understand scavenger will print incorrect numbers now,
as stack usage is not subtracted from heap. But it's better than deadlocking.
LGTM=khr
R=golang-codereviews, rsc, khr
CC=golang-codereviews, rlh
https://golang.org/cl/124670043
Diffstat (limited to 'src/pkg/runtime/proc.c')
| -rw-r--r-- | src/pkg/runtime/proc.c | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/src/pkg/runtime/proc.c b/src/pkg/runtime/proc.c index 2510a421a8..8584cb6f6a 100644 --- a/src/pkg/runtime/proc.c +++ b/src/pkg/runtime/proc.c @@ -498,6 +498,14 @@ runtime·stoptheworld(void) P *p; bool wait; + // If we hold a lock, then we won't be able to stop another M + // that is blocked trying to acquire the lock. + if(g->m->locks > 0) + runtime·throw("stoptheworld: holding locks"); + // There is no evidence that stoptheworld on g0 does not work, + // we just don't do it today. + if(g == g->m->g0) + runtime·throw("stoptheworld: on g0"); runtime·lock(&runtime·sched.lock); runtime·sched.stopwait = runtime·gomaxprocs; runtime·atomicstore((uint32*)&runtime·sched.gcwaiting, 1); |