From: Florent Fourcot <florent.fourcot@enst-bretagne.fr>
Date: Thu, 7 Nov 2013 16:53:14 +0000 (+0100)
Subject: ipv6: protect flow label renew against GC
X-Git-Tag: accepted/tizen/common/20141203.182822~1141^2~18
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=394055f6fabd077e74815865f01a73a31dd765d3;p=platform%2Fkernel%2Flinux-arm64.git

ipv6: protect flow label renew against GC

Take ip6_fl_lock before to read and update
a label.

v2: protect only the relevant code

Reported-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: Florent Fourcot <florent.fourcot@enst-bretagne.fr>
Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
---

diff --git a/net/ipv6/ip6_flowlabel.c b/net/ipv6/ip6_flowlabel.c
index 5f10b0d..98fdcc6 100644
--- a/net/ipv6/ip6_flowlabel.c
+++ b/net/ipv6/ip6_flowlabel.c
@@ -345,6 +345,8 @@ static int fl6_renew(struct ip6_flowlabel *fl, unsigned long linger, unsigned lo
 	expires = check_linger(expires);
 	if (!expires)
 		return -EPERM;
+
+	spin_lock_bh(&ip6_fl_lock);
 	fl->lastuse = jiffies;
 	if (time_before(fl->linger, linger))
 		fl->linger = linger;
@@ -352,6 +354,8 @@ static int fl6_renew(struct ip6_flowlabel *fl, unsigned long linger, unsigned lo
 		expires = fl->linger;
 	if (time_before(fl->expires, fl->lastuse + expires))
 		fl->expires = fl->lastuse + expires;
+	spin_unlock_bh(&ip6_fl_lock);
+
 	return 0;
 }