From 2e6683c33bb5252d1beceb7b66cee406783fc234 Mon Sep 17 00:00:00 2001 From: Nikolay Aleksandrov Date: Thu, 11 Apr 2019 15:08:25 +0300 Subject: [PATCH] net: bridge: multicast: use rcu to access port list from br_multicast_start_querier commit c5b493ce192bd7a4e7bd073b5685aad121eeef82 upstream. br_multicast_start_querier() walks over the port list but it can be called from a timer with only multicast_lock held which doesn't protect the port list, so use RCU to walk over it. Fixes: c83b8fab06fc ("bridge: Restart queries when last querier expires") Change-Id: Ic030f401e560c16f919e03cb987201869e3926b7 Signed-off-by: Nikolay Aleksandrov Signed-off-by: David S. Miller Signed-off-by: Ben Hutchings --- net/bridge/br_multicast.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/net/bridge/br_multicast.c b/net/bridge/br_multicast.c index a09ea178348c..15f2525099c4 100644 --- a/net/bridge/br_multicast.c +++ b/net/bridge/br_multicast.c @@ -1772,13 +1772,15 @@ static void br_multicast_start_querier(struct net_bridge *br) br_multicast_open(br); - list_for_each_entry(port, &br->port_list, list) { + rcu_read_lock(); + list_for_each_entry_rcu(port, &br->port_list, list) { if (port->state == BR_STATE_DISABLED || port->state == BR_STATE_BLOCKING) continue; __br_multicast_enable_port(port); } + rcu_read_unlock(); } int br_multicast_toggle(struct net_bridge *br, unsigned long val)