From: Ido Schimmel <idosch@nvidia.com>
To: netdev@vger.kernel.org, bridge@lists.linux.dev
Cc: davem@davemloft.net, kuba@kernel.org, pabeni@redhat.com,
edumazet@kernel.org, razor@blackwall.org, horms@kernel.org,
petrm@nvidia.com, yunlong_ma@buaa.edu.cn,
Ido Schimmel <idosch@nvidia.com>
Subject: [PATCH net 0/2] bridge: mcast: Fix MDB exhaustion by rejected entries
Date: Fri, 16 Oct 2026 13:14:05 +0300 [thread overview]
Message-ID: <20261016101407.2030133-1-idosch@nvidia.com> (raw)
When the bridge fails to create a port group for a new MDB entry, the
entry is left behind with no ports and is never deleted, but it is still
counted towards mcast_hash_max. Since the introduction of
mcast_max_groups, a host behind a port that reached its maximum can use
this to exhaust the MDB and disable multicast snooping.
Patch #1 fixes the problem by deleting the entry upon failure.
Patch #2 adds a selftest.
Ido Schimmel (2):
bridge: mcast: Delete empty MDB entry when port group creation fails
selftests: forwarding: bridge_mdb_max: Add a test for rejected MDB
entries
net/bridge/br_mdb.c | 16 +-
net/bridge/br_multicast.c | 9 ++
net/bridge/br_private.h | 1 +
.../net/forwarding/bridge_mdb_max.sh | 138 ++++++++++++++++++
4 files changed, 161 insertions(+), 3 deletions(-)
--
2.56.0
next reply other threads:[~2026-10-16 10:15 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-10-16 10:14 Ido Schimmel [this message]
2026-10-16 10:14 ` [PATCH net 1/2] bridge: mcast: Delete empty MDB entry when port group creation fails Ido Schimmel
2026-10-16 10:14 ` [PATCH net 2/2] selftests: forwarding: bridge_mdb_max: Add a test for rejected MDB entries Ido Schimmel
2026-10-16 15:51 ` [PATCH net 0/2] bridge: mcast: Fix MDB exhaustion by rejected entries Gabriel Goller
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