From 159ad90cb929c033308bb39a2c5f8fbf393b77aa Mon Sep 17 00:00:00 2001 From: Zhiling Zou Date: Fri, 24 Jul 2026 00:52:48 +0800 Subject: [PATCH] net: bridge: stop fast-leave after deleting a port group commit a39789f211b8a4125f0c70e05b30cf715f4f187d upstream. br_multicast_leave_group() iterates mp->ports with pp = &p->next in its fast-leave path. After br_multicast_del_pg() removes p, continuing the loop advances pp through the deleted entry. If multicast-to-unicast was enabled, the bridge can hold multiple port groups for the same port and group with different source MAC addresses. Once multicast-to-unicast is disabled, br_port_group_equal() matches those entries by port only. A fast leave can then delete one entry and continue from its stale next pointer, leaving mp->ports pointing at a deleted port group. Fast leave only needs to remove one matching port group. Break after br_multicast_del_pg() so the loop stops before dereferencing the removed entry. Fixes: 6db6f0eae605 ("bridge: multicast to unicast") Cc: stable@vger.kernel.org Reported-by: Vega Signed-off-by: Zhiling Zou Signed-off-by: Ren Wei Acked-by: Nikolay Aleksandrov Link: https://patch.msgid.link/1cf0898872ef7c72d5f4c0304414a192c6dac591.1784707712.git.zhilinz@nebusec.ai Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman --- net/bridge/br_multicast.c | 1 + 1 file changed, 1 insertion(+) diff --git a/net/bridge/br_multicast.c b/net/bridge/br_multicast.c index 9c91b663bc3b..1625a0776800 100644 --- a/net/bridge/br_multicast.c +++ b/net/bridge/br_multicast.c @@ -3684,6 +3684,7 @@ br_multicast_leave_group(struct net_bridge_mcast *brmctx, p->flags |= MDB_PG_FLAGS_FAST_LEAVE; br_multicast_del_pg(mp, p, pp); + break; } goto out; }