From 53056c37c2e3720666742f516ef148432313e28a Mon Sep 17 00:00:00 2001
From: Dmitriy Vyukov <dvyukov@google.com>
Date: Tue, 19 Aug 2014 11:49:36 +0400
Subject: [PATCH] cmd/gc: fix heap buffer overflow Fixes #8528.

LGTM=rsc
R=rsc, r, iant, bradfitz
CC=golang-codereviews
https://golang.org/cl/128230045
---
 src/cmd/gc/bv.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/src/cmd/gc/bv.c b/src/cmd/gc/bv.c
index 0e8f8d4739..cfd1cd2811 100644
--- a/src/cmd/gc/bv.c
+++ b/src/cmd/gc/bv.c
@@ -108,6 +108,9 @@ bvnext(Bvec *bv, int32 i)
 {
 	uint32 w;
 
+	if(i >= bv->n)
+		return -1;
+
 	// Jump i ahead to next word with bits.
 	if((bv->b[i>>WORDSHIFT]>>(i&WORDMASK)) == 0) {
 		i &= ~WORDMASK;
@@ -117,7 +120,7 @@ bvnext(Bvec *bv, int32 i)
 	}
 	if(i >= bv->n)
 		return -1;
-	
+
 	// Find 1 bit.
 	w = bv->b[i>>WORDSHIFT]>>(i&WORDMASK);
 	while((w&1) == 0) {
-- 
2.48.1