From 5761d00bf5760f044224fd7a7500942ff7ba973c Mon Sep 17 00:00:00 2001
From: Davidlohr Bueso <dave@gnu.org>
Date: Thu, 4 Oct 2012 17:13:18 -0700
Subject: [PATCH] lib/gcd.c: prevent possible div by 0

commit e96875677fb2b7cb739c5d7769824dff7260d31d upstream.

Account for all properties when a and/or b are 0:
gcd(0, 0) = 0
gcd(a, 0) = a
gcd(0, b) = b

Fixes no known problems in current kernels.

Signed-off-by: Davidlohr Bueso <dave@gnu.org>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 lib/gcd.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/lib/gcd.c b/lib/gcd.c
index cce4f3cd14b3..3657f129d7b8 100644
--- a/lib/gcd.c
+++ b/lib/gcd.c
@@ -9,6 +9,9 @@ unsigned long gcd(unsigned long a, unsigned long b)
 
 	if (a < b)
 		swap(a, b);
+
+	if (!b)
+		return a;
 	while ((r = a % b) != 0) {
 		a = b;
 		b = r;
-- 
2.39.5