From: Nikolay Aleksandrov <nikolay@nvidia.com> stable inclusion from linux-4.19.198 commit 2e70bf39b1a96b40ab13044729613a913b46cddd -------------------------------- commit 04bef83a3358946bfc98a5ecebd1b0003d83d882 upstream. When a PIM hello packet is received on a bridge port with multicast snooping enabled, we mark it as a router port automatically, that includes adding that port the router port list. The multicast lock protects that list, but it is not acquired in the PIM message case leading to a race condition, we need to take it to fix the race. Cc: stable@vger.kernel.org Fixes: 91b02d3d133b ("bridge: mcast: add router port on PIM hello message") Signed-off-by: Nikolay Aleksandrov <nikolay@nvidia.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Yang Yingliang <yangyingliang@huawei.com> --- net/bridge/br_multicast.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/net/bridge/br_multicast.c b/net/bridge/br_multicast.c index 6a362da211e1b..3504c3acd38f6 100644 --- a/net/bridge/br_multicast.c +++ b/net/bridge/br_multicast.c @@ -1791,7 +1791,9 @@ static void br_multicast_pim(struct net_bridge *br, pim_hdr_type(pimhdr) != PIM_TYPE_HELLO) return; + spin_lock(&br->multicast_lock); br_multicast_mark_router(br, port); + spin_unlock(&br->multicast_lock); } static int br_multicast_ipv4_rcv(struct net_bridge *br, -- 2.25.1