From: Dmitriy Vyukov <dvyukov@google.com>
Date: Mon, 24 Dec 2012 17:06:57 +0000 (+0400)
Subject: runtime: diagnose double wakeup on Note
X-Git-Tag: go1.1rc2~1531
X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=4380fa6d99284c03e471bafcb1be2db83b225af4;p=gostls13.git

runtime: diagnose double wakeup on Note
Double wakeup is prohibited by the Note interface
and checked in lock_sema.c.

R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/6976054
---

diff --git a/src/pkg/runtime/lock_futex.c b/src/pkg/runtime/lock_futex.c
index b4465bff18..9b1f5f6db4 100644
--- a/src/pkg/runtime/lock_futex.c
+++ b/src/pkg/runtime/lock_futex.c
@@ -111,7 +111,8 @@ runtime·noteclear(Note *n)
 void
 runtime·notewakeup(Note *n)
 {
-	runtime·xchg(&n->key, 1);
+	if(runtime·xchg(&n->key, 1))
+		runtime·throw("notewakeup - double wakeup");
 	runtime·futexwakeup(&n->key, 1);
 }