linux-kernel - [PATCH v2] lib: gcd: prevent possible div by 0

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Message-ID: <1347287719.2561.14.camel@offbook>
Date:	Mon, 10 Sep 2012 16:35:19 +0200
From:	Davidlohr Bueso <dave@....org>
To:	Eric Dumazet <eric.dumazet@...il.com>,
	Andrew Morton <akpm@...ux-foundation.org>
Cc:	lkml <linux-kernel@...r.kernel.org>, stable@...r.kernel.org
Subject: [PATCH v2] lib: gcd: prevent possible div by 0

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

Cc: stable@...r.kernel.org
Signed-off-by: Davidlohr Bueso <dave@....org>
---
V2: simplified checking with b = 0 (Eric)

 lib/gcd.c |    3 +++
 1 file changed, 3 insertions(+)

diff --git a/lib/gcd.c b/lib/gcd.c
index cce4f3c..3657f12 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;
-- 
1.7.9.5



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