From c1e7e01e2edb90678e26f100fae0dc50024d139b 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 [ Upstream commit c5b493ce192bd7a4e7bd073b5685aad121eeef82 ] 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") Signed-off-by: Nikolay Aleksandrov Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- 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 8dc5c8d69bcd..e83048cb53ce 100644 --- a/net/bridge/br_multicast.c +++ b/net/bridge/br_multicast.c @@ -2119,7 +2119,8 @@ static void br_multicast_start_querier(struct net_bridge *br, __br_multicast_open(br, query); - 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; @@ -2131,6 +2132,7 @@ static void br_multicast_start_querier(struct net_bridge *br, br_multicast_enable(&port->ip6_own_query); #endif } + rcu_read_unlock(); } int br_multicast_toggle(struct net_bridge *br, unsigned long val) -- 2.20.1