From: Andrey Vagin <avagin@openvz.org>
Date: Thu, 10 Nov 2011 05:48:03 +0000 (+0000)
Subject: bridge: Fix potential deadlock on br->multicast_lock
X-Git-Tag: v3.2-rc3~25^2~42
X-Git-Url: https://openfabrics.org/gitweb/?a=commitdiff_plain;h=ef5e0d8237287db3a12d84f08fb2483d7a30a943;p=~emulex%2Finfiniband.git

bridge: Fix potential deadlock on br->multicast_lock

multicast_lock is taken in softirq context, so we should use
spin_lock_bh() in userspace.

call-chain in softirq context:
run_timer_softirq()
	br_multicast_query_expired()

call-chain in userspace:
sysfs_write_file()
	store_multicast_snooping()
		br_multicast_toggle()

Signed-off-by: Andrew Vagin <avagin@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
---

diff --git a/net/bridge/br_multicast.c b/net/bridge/br_multicast.c
index 995cbe0ac0b..2eefe275b33 100644
--- a/net/bridge/br_multicast.c
+++ b/net/bridge/br_multicast.c
@@ -1770,7 +1770,7 @@ int br_multicast_toggle(struct net_bridge *br, unsigned long val)
 	int err = 0;
 	struct net_bridge_mdb_htable *mdb;
 
-	spin_lock(&br->multicast_lock);
+	spin_lock_bh(&br->multicast_lock);
 	if (br->multicast_disabled == !val)
 		goto unlock;
 
@@ -1806,7 +1806,7 @@ rollback:
 	}
 
 unlock:
-	spin_unlock(&br->multicast_lock);
+	spin_unlock_bh(&br->multicast_lock);
 
 	return err;
 }