runtime: call atomic.Storeuintptr in noteclear on AIX

The memory might not be synchronized in a thread being woken up after a semasleep. Using atomic instructions in noteclear function will force this synchronisation. Fixes #30189 Change-Id: If7432f29b2a1a56288231822db52f3f8d1d6dbfe Reviewed-on: https://go-review.googlesource.com/c/go/+/163624 Run-TryBot: Ian Lance Taylor <[email protected]> TryBot-Result: Gobot Gobot <[email protected]> Reviewed-by: Ian Lance Taylor <[email protected]>
golang · May 14, 2019 · 1956b28 · 1956b28
1 parent 46e03c4
commit 1956b28
Showing 1 changed file with 7 additions and 1 deletion.
diff --git a/src/runtime/lock_sema.go b/src/runtime/lock_sema.go
@@ -122,7 +122,13 @@ func unlock(l *mutex) {
 
 // One-time notifications.
 func noteclear(n *note) {
-	n.key = 0
+	if GOOS == "aix" {
+		// On AIX, semaphores might not synchronize the memory in some
+		// rare cases. See issue #30189.
+		atomic.Storeuintptr(&n.key, 0)
+	} else {
+		n.key = 0
+	}
 }
 
 func notewakeup(n *note) {