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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, Ido Schimmel <idosch@mellanox.com>,
        Jiri Pirko <jiri@mellanox.com>,
        "David S. Miller" <davem@davemloft.net>,
        Sasha Levin <alexander.levin@microsoft.com>
Subject: [PATCH 4.9 076/310] mlxsw: spectrum: Avoid possible NULL pointer dereference
Date:   Wed, 11 Apr 2018 20:33:35 +0200
Message-Id: <20180411183625.582544217@linuxfoundation.org>
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4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Ido Schimmel <idosch@mellanox.com>


[ Upstream commit c0e01eac7ada785fdeaea1ae5476ec1cf3b00374 ]

In case we got an FDB notification for a port that doesn't exist we
execute an FDB entry delete to prevent it from re-appearing the next
time we poll for notifications.

If the operation failed we would trigger a NULL pointer dereference as
'mlxsw_sp_port' is NULL.

Fix it by reporting the error using the underlying bus device instead.

Fixes: 12f1501e7511 ("mlxsw: spectrum: remove FDB entry in case we get unknown object notification")
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/net/ethernet/mellanox/mlxsw/spectrum_switchdev.c |    6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

--- a/drivers/net/ethernet/mellanox/mlxsw/spectrum_switchdev.c
+++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum_switchdev.c
@@ -1448,8 +1448,7 @@ do_fdb_op:
 	err = mlxsw_sp_port_fdb_uc_op(mlxsw_sp, local_port, mac, fid,
 				      adding, true);
 	if (err) {
-		if (net_ratelimit())
-			netdev_err(mlxsw_sp_port->dev, "Failed to set FDB entry\n");
+		dev_err_ratelimited(mlxsw_sp->bus_info->dev, "Failed to set FDB entry\n");
 		return;
 	}
 
@@ -1509,8 +1508,7 @@ do_fdb_op:
 	err = mlxsw_sp_port_fdb_uc_lag_op(mlxsw_sp, lag_id, mac, fid, lag_vid,
 					  adding, true);
 	if (err) {
-		if (net_ratelimit())
-			netdev_err(mlxsw_sp_port->dev, "Failed to set FDB entry\n");
+		dev_err_ratelimited(mlxsw_sp->bus_info->dev, "Failed to set FDB entry\n");
 		return;
 	}