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>
diff --git a/src/runtime/proc.go b/src/runtime/proc.go
index 341d52a..739745a 100644
--- a/src/runtime/proc.go
+++ b/src/runtime/proc.go
@@ -3928,6 +3928,13 @@
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).
