3.19.8-ckt3 -stable review patch. If anyone has any objections, please let me know.
------------------ From: Wilson Kok <[email protected]> commit 1d7c49037b12016e7056b9f2c990380e2187e766 upstream. br_fdb_update() can be called in process context in the following way: br_fdb_add() -> __br_fdb_add() -> br_fdb_update() (if NTF_USE flag is set) so we need to use spin_lock_bh because there are softirq users of the hash_lock. One easy way to reproduce this is to modify the bridge utility to set NTF_USE, enable stp and then set maxageing to a low value so br_fdb_cleanup() is called frequently and then just add new entries in a loop. This happens because br_fdb_cleanup() is called from timer/softirq context. These locks were _bh before commit f8ae737deea1 ("[BRIDGE]: forwarding remove unneeded preempt and bh diasables") and at the time that commit was correct because br_fdb_update() couldn't be called from process context, but that changed after commit: 292d1398983f ("bridge: add NTF_USE support") Signed-off-by: Wilson Kok <[email protected]> Signed-off-by: Nikolay Aleksandrov <[email protected]> Fixes: 292d1398983f ("bridge: add NTF_USE support") Signed-off-by: David S. Miller <[email protected]> Signed-off-by: Kamal Mostafa <[email protected]> --- net/bridge/br_fdb.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/net/bridge/br_fdb.c b/net/bridge/br_fdb.c index 79f59c5..ed1e0fa 100644 --- a/net/bridge/br_fdb.c +++ b/net/bridge/br_fdb.c @@ -569,7 +569,7 @@ void br_fdb_update(struct net_bridge *br, struct net_bridge_port *source, fdb_notify(br, fdb, RTM_NEWNEIGH); } } else { - spin_lock(&br->hash_lock); + spin_lock_bh(&br->hash_lock); if (likely(!fdb_find(head, addr, vid))) { fdb = fdb_create(head, source, addr, vid); if (fdb) { @@ -581,7 +581,7 @@ void br_fdb_update(struct net_bridge *br, struct net_bridge_port *source, /* else we lose race and someone else inserts * it first, don't bother updating */ - spin_unlock(&br->hash_lock); + spin_unlock_bh(&br->hash_lock); } } -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
