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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Vladimir Oltean <vladimir.oltean@nxp.com>,
        "David S. Miller" <davem@davemloft.net>
Subject: [PATCH 5.10 109/125] net: dsa: properly check for the bridge_leave methods in dsa_switch_bridge_leave()
Date:   Thu, 22 Jul 2021 18:31:40 +0200
Message-Id: <20210722155628.328379252@linuxfoundation.org>
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From: Vladimir Oltean <vladimir.oltean@nxp.com>

commit bcb9928a155444dbd212473e60241ca0a7f641e1 upstream.

This was not caught because there is no switch driver which implements
the .port_bridge_join but not .port_bridge_leave method, but it should
nonetheless be fixed, as in certain conditions (driver development) it
might lead to NULL pointer dereference.

Fixes: f66a6a69f97a ("net: dsa: permit cross-chip bridging between all trees in the system")
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 net/dsa/switch.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/net/dsa/switch.c
+++ b/net/dsa/switch.c
@@ -112,11 +112,11 @@ static int dsa_switch_bridge_leave(struc
 	int err, i;
 
 	if (dst->index == info->tree_index && ds->index == info->sw_index &&
-	    ds->ops->port_bridge_join)
+	    ds->ops->port_bridge_leave)
 		ds->ops->port_bridge_leave(ds, info->port, info->br);
 
 	if ((dst->index != info->tree_index || ds->index != info->sw_index) &&
-	    ds->ops->crosschip_bridge_join)
+	    ds->ops->crosschip_bridge_leave)
 		ds->ops->crosschip_bridge_leave(ds, info->tree_index,
 						info->sw_index, info->port,
 						info->br);