From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793211553; b=Sg9Eo2ATMLhItgfFHL2QQdvX6wRbGZabeS3vIGx1e9sFKL25kEiBqdHW3rxfHugwEOFr l6NL6e5fwq0KIb8pZFaCdPLvKgNA3uA6PeFxROeFBsAsFF1cqcpz9h6XBYp+IcaVu1Qox ZOJ1ofASkOD5ppZqru+NMIj2fzUGBmpOoIkk2W51KTOE7tWRR12vmktgR67g21sTzasiH Y3nL6jld6m7dAZoAmVVzPHDVVdcfhdDi7UpPsOFbXPMrrl0WPGFu3X/y9AZfXzf/jO8k8 IW4uvPsCIdPL5b75XfLVQimwSaSizfwQkOQUuxQmOtFVe3gBPkBq+nxYRTImYnBek1g== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793211553; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:User-Agent:X-stable:X-Patchwork-Hint: MIME-Version:Content-Transfer-Encoding; bh=ig9Xy0PfJtSxqUaW5FqndI7B/QewKPxQ5wTctk6r4X8=; b=PzwUyWiEUsj/aTSrMh/9YT1JZL67EHvQ67ju4j4cgBJ70CpHOGjfENwebuwUi8zPtjI/ xE0srrbC+tE3aDuoI+j8XQDs8QuseWEdhWZVuRZVc/G9+jiUny7miluLT/uVby7iO9Nqj KXEDy2SBTTcIJMvEv0hhB3LgA++CPowTCpPKXe5XcWvV/kuCoQsczJYqRRC7ezAILn5Te YbTDkRBd0h5IuBb+mAfYjFPfIdDnAz3pppjMwj/RnBV6wkrZeW9uhG3gdLcbHwswQE7+P tEs2cOEeJAKSjF32by/I0Lko2FPu1EsA6iwj5V8he4muHJ3RCbrmV8NuteXyrJ6AHHQ== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=K6k4VpGY; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 17846606A31A; Wed, 28 Oct 2026 18:19:13 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key, unprotected) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=K6k4VpGY Received: by smtp.kernel.org (Postfix) with ESMTPSA id 654911F01825; Wed, 28 Oct 2026 18:19:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1793211552; bh=ig9Xy0PfJtSxqUaW5FqndI7B/QewKPxQ5wTctk6r4X8=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=K6k4VpGYtb0/Dzpg4rrPCEo2bvL30gyovi8ZiQ3DaWAKjnzwBOKJe0+HkT+ZJ4S20 Wr+5iqeRNbfVep0qmpKND4/kqaQkh70tnxux5bxRg2YkdBYxmms8w0taWk2/hBMHFi 5md8Wc+NZtDRURjHT9VsrayrCKYouPvZ/fDpSEU8= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Vega , Zixuan Chai , Ren Wei , "David S. Miller" Subject: [PATCH 5.15 373/571] net: bridge: avoid recursive multicast port cleanup Date: Wed, 28 Oct 2026 17:58:40 +0100 Message-ID: <20261028170016.863522557@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261028170008.009143722@linuxfoundation.org> References: <20261028170008.009143722@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore X-Mailing-List: patches@lists.linux.dev List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Zixuan Chai commit 5158353121bae4f552cb677ce8c5c3ef52f93a0d upstream. br_multicast_sg_del_exclude_ports() removes automatically added STAR_EXCL port groups by calling br_multicast_del_pg(). For S,G entries, that deletion calls back into br_multicast_sg_del_exclude_ports(), so a large number of STAR_EXCL ports consumes one kernel stack frame per port and can hit the stack guard page. Keep the complete port-group deletion path for cleanup, but suppress the S,G exclude-port cleanup while that helper is already walking the same entry. Normal deletion callers retain the existing behavior. Fixes: 8266a0491e92 ("net: bridge: mcast: handle port group filter modes") Cc: stable@vger.kernel.org Reported-by: Vega Assisted-by: LLM Signed-off-by: Zixuan Chai Signed-off-by: Ren Wei Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/bridge/br_multicast.c | 23 ++++++++++++++++++----- 1 file changed, 18 insertions(+), 5 deletions(-) --- a/net/bridge/br_multicast.c +++ b/net/bridge/br_multicast.c @@ -80,6 +80,10 @@ __br_multicast_add_group(struct net_brid bool blocked); static void br_multicast_find_del_pg(struct net_bridge *br, struct net_bridge_port_group *pg); +static void __br_multicast_del_pg(struct net_bridge_mdb_entry *mp, + struct net_bridge_port_group *pg, + struct net_bridge_port_group __rcu **pp, + bool sg_del_exclude_ports); static void __br_multicast_stop(struct net_bridge_mcast *brmctx); static int br_mc_disabled_update(struct net_device *dev, bool value, @@ -436,7 +440,7 @@ static void br_multicast_sg_del_exclude_ for (pp = &sgmp->ports; (p = mlock_dereference(*pp, sgmp->br)) != NULL;) { if (!(p->flags & MDB_PG_FLAGS_PERMANENT)) - br_multicast_del_pg(sgmp, p, pp); + __br_multicast_del_pg(sgmp, p, pp, false); else pp = &p->next; } @@ -675,9 +679,10 @@ static void br_multicast_destroy_port_gr kfree_rcu(pg, rcu); } -void br_multicast_del_pg(struct net_bridge_mdb_entry *mp, - struct net_bridge_port_group *pg, - struct net_bridge_port_group __rcu **pp) +static void __br_multicast_del_pg(struct net_bridge_mdb_entry *mp, + struct net_bridge_port_group *pg, + struct net_bridge_port_group __rcu **pp, + bool sg_del_exclude_ports) { struct net_bridge *br = pg->key.port->br; struct net_bridge_group_src *ent; @@ -692,7 +697,8 @@ void br_multicast_del_pg(struct net_brid if (!br_multicast_is_star_g(&mp->addr)) { rhashtable_remove_fast(&br->sg_port_tbl, &pg->rhnode, br_sg_port_rht_params); - br_multicast_sg_del_exclude_ports(mp); + if (sg_del_exclude_ports) + br_multicast_sg_del_exclude_ports(mp); } else { br_multicast_star_g_handle_mode(pg, MCAST_INCLUDE); } @@ -703,6 +709,13 @@ void br_multicast_del_pg(struct net_brid mod_timer(&mp->timer, jiffies); } +void br_multicast_del_pg(struct net_bridge_mdb_entry *mp, + struct net_bridge_port_group *pg, + struct net_bridge_port_group __rcu **pp) +{ + __br_multicast_del_pg(mp, pg, pp, true); +} + static void br_multicast_find_del_pg(struct net_bridge *br, struct net_bridge_port_group *pg) {