This is a note to let you know that I've just added the patch titled net: bridge: multicast: fix PIM hello router port marking race to the 5.13-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: net-bridge-multicast-fix-pim-hello-router-port-marking-race.patch and it can be found in the queue-5.13 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 04bef83a3358946bfc98a5ecebd1b0003d83d882 Mon Sep 17 00:00:00 2001 From: Nikolay Aleksandrov <nikolay@xxxxxxxxxx> Date: Sun, 11 Jul 2021 12:56:28 +0300 Subject: net: bridge: multicast: fix PIM hello router port marking race From: Nikolay Aleksandrov <nikolay@xxxxxxxxxx> 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@xxxxxxxxxxxxxxx Fixes: 91b02d3d133b ("bridge: mcast: add router port on PIM hello message") Signed-off-by: Nikolay Aleksandrov <nikolay@xxxxxxxxxx> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- net/bridge/br_multicast.c | 2 ++ 1 file changed, 2 insertions(+) --- a/net/bridge/br_multicast.c +++ b/net/bridge/br_multicast.c @@ -3087,7 +3087,9 @@ static void br_multicast_pim(struct net_ 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_ip4_multicast_mrd_rcv(struct net_bridge *br, Patches currently in stable-queue which might be from nikolay@xxxxxxxxxx are queue-5.13/net-bridge-multicast-fix-mrd-advertisement-router-port-marking-race.patch queue-5.13/net-bridge-multicast-fix-pim-hello-router-port-marking-race.patch