From 7157a527af680c157244db79f2d7f15d889f2ad1 Mon Sep 17 00:00:00 2001 From: stephen hemminger Date: Thu, 2 May 2013 14:23:28 +0000 Subject: [PATCH] bridge: fix race with topology change timer [ Upstream commit 83401eb4990ff6af55aeed8f49681558544192e6 ] A bridge should only send topology change notice if it is not the root bridge. It is possible for message age timer to elect itself as a new root bridge, and still have a topology change timer running but waiting for bridge lock on other CPU. Solve the race by checking if we are root bridge before continuing. This was the root cause of the cases where br_send_tcn_bpdu would OOPS. Reported-by: JerryKang Signed-off-by: Stephen Hemminger Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/bridge/br_stp_timer.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/bridge/br_stp_timer.c b/net/bridge/br_stp_timer.c index 58de2a0..c83ee79 100644 --- a/net/bridge/br_stp_timer.c +++ b/net/bridge/br_stp_timer.c @@ -107,7 +107,7 @@ static void br_tcn_timer_expired(unsigned long arg) br_debug(br, "tcn timer expired\n"); spin_lock(&br->lock); - if (br->dev->flags & IFF_UP) { + if (!br_is_root_bridge(br) && (br->dev->flags & IFF_UP)) { br_transmit_tcn(br); mod_timer(&br->tcn_timer,jiffies + br->bridge_hello_time); -- 2.7.4