On Wed, Jun 10, 2026 at 10:31:23AM +0200, Cedric Jehasse via B4 Relay wrote: > From: Cedric Jehasse <[email protected]> > > For a static L2 multicast group that has both a host entry and a port > entry, deleting the port entry also removes the host entry, and the > whole group then disappears from "bridge mdb show". > > To reproduce: > bridge mdb add dev br0 port br0 grp 01:02:03:04:05:06 permanent > bridge mdb add dev br0 port swp1 grp 01:02:03:04:05:06 permanent > bridge mdb del dev br0 port swp1 grp 01:02:03:04:05:06 permanent > bridge mdb show # the "port br0" host entry is gone, too
Please show the output in the commit message and also show that this differs from regular (*, G) entries where the host entry is not removed following the deletion of the port entry. > > br_multicast_del_pg() processes every non-(*,G) entry through the S,G > path, which removes the port group from br->sg_port_tbl and then calls > br_multicast_sg_del_exclude_ports(). L2 entries are stored in > sg_port_tbl as well, so they take this path too. > > When the last port is removed in br_multicast_sg_del_exclude_ports it > sets "sgmp->host_joined = false", clearing the host membership directly > and bypassing br_multicast_host_leave(). With host_joined now false and > no ports left, br_multicast_del_pg() arms the group timer and > br_multicast_group_expired() tears down the whole mdb entry -- even > though the host membership was explicitly and permanently configured > from user space. > > Keep removing L2 port groups from sg_port_tbl, but skip the S,G > EXCLUDE-mode handling for them. The host membership of an L2 group is > managed solely via br_multicast_host_join() / br_multicast_host_leave(). > > Signed-off-by: Cedric Jehasse <[email protected]> The patch seems OK to me, but please add a test case in bridge_mdb.sh. I checked the code and AFAICT this never worked, so target at net-next without a fixes tag: Support for L2 multicast groups was added in 955062b03fa62, but at this point the mode handling already existed in br_multicast_del_pg().
