linux-kernel - [PATCH net] net: dsa: b53: skip multicast entries for fdb

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Message-ID: <20251217205756.172123-1-jonas.gorski@gmail.com>
Date: Wed, 17 Dec 2025 21:57:56 +0100
From: Jonas Gorski <jonas.gorski@...il.com>
To: Florian Fainelli <florian.fainelli@...adcom.com>,
	Andrew Lunn <andrew@...n.ch>,
	Vladimir Oltean <olteanv@...il.com>,
	"David S. Miller" <davem@...emloft.net>,
	Eric Dumazet <edumazet@...gle.com>,
	Jakub Kicinski <kuba@...nel.org>,
	Paolo Abeni <pabeni@...hat.com>
Cc: Florian Fainelli <f.fainelli@...il.com>,
	netdev@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH net] net: dsa: b53: skip multicast entries for fdb_dump()

port_fdb_dump() is supposed to only add fdb entries, but we iterate over
the full ARL table, which also inludes multicast entries.

So check if the entry is a multicast entry before passing it on to the
callback().

Additionally, the port of those entries is a bitmask, not a port number,
so any included entries would have even be for the wrong port.

Fixes: 1da6df85c6fb ("net: dsa: b53: Implement ARL add/del/dump operations")
Signed-off-by: Jonas Gorski <jonas.gorski@...il.com>
---
 drivers/net/dsa/b53/b53_common.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/net/dsa/b53/b53_common.c b/drivers/net/dsa/b53/b53_common.c
index a1a177713d99..2c4131ed7e30 100644
--- a/drivers/net/dsa/b53/b53_common.c
+++ b/drivers/net/dsa/b53/b53_common.c
@@ -2169,6 +2169,9 @@ static int b53_fdb_copy(int port, const struct b53_arl_entry *ent,
 	if (!ent->is_valid)
 		return 0;
 
+	if (is_multicast_ether_addr(ent->mac))
+		return 0;
+
 	if (port != ent->port)
 		return 0;
 
-- 
2.43.0