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| author | Ian Lance Taylor <iant@golang.org> | 2020-09-09 10:40:11 -0700 |
|---|---|---|
| committer | Ian Lance Taylor <iant@golang.org> | 2020-09-09 18:04:10 +0000 |
| commit | 2556eb76c8e752907600274d323a52e97418d14f (patch) | |
| tree | b96ff9b9ae8d3d87cc25ac6a5b3346773dd10fe1 | |
| parent | 34835df04891a1d54394888b763af88f9476101d (diff) | |
| download | go-2556eb76c8e752907600274d323a52e97418d14f.tar.gz go-2556eb76c8e752907600274d323a52e97418d14f.zip | |
runtime: ignore SIGPROF if profiling disable for thread
This avoids a deadlock on prof.signalLock between setcpuprofilerate
and cpuprof.add if a SIGPROF is delivered to the thread between the
call to setThreadCPUProfiler and acquiring prof.signalLock.
Fixes #41014
Change-Id: Ie825e8594f93a19fb1a6320ed640f4e631553596
Reviewed-on: https://go-review.googlesource.com/c/go/+/253758
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Bryan C. Mills <bcmills@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
| -rw-r--r-- | src/runtime/proc.go | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/src/runtime/proc.go b/src/runtime/proc.go index 341d52aea8..739745aa26 100644 --- a/src/runtime/proc.go +++ b/src/runtime/proc.go @@ -3928,6 +3928,13 @@ func sigprof(pc, sp, lr uintptr, gp *g, mp *m) { return } + // If mp.profilehz is 0, then profiling is not enabled for this thread. + // We must check this to avoid a deadlock between setcpuprofilerate + // and the call to cpuprof.add, below. + if mp != nil && mp.profilehz == 0 { + return + } + // On mips{,le}, 64bit atomics are emulated with spinlocks, in // runtime/internal/atomic. If SIGPROF arrives while the program is inside // the critical section, it creates a deadlock (when writing the sample). |