From: Zhiling Zou 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 Assisted-by: Codex:gpt-5.4 Signed-off-by: Zhiling Zou Signed-off-by: Ren Wei --- 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 6b3ac473fd22..00aa9b2879d6 100644 --- a/net/bridge/br_multicast.c +++ b/net/bridge/br_multicast.c @@ -3687,6 +3687,7 @@ 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; } -- 2.43.0