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From:   Arnd Bergmann <arnd@arndb.de>
To:     Jiri Pirko <jiri@mellanox.com>, Ido Schimmel <idosch@mellanox.com>,
        "David S. Miller" <davem@davemloft.net>
Cc:     Arnd Bergmann <arnd@arndb.de>, Petr Machata <petrm@mellanox.com>,
        Arkadi Sharshevsky <arkadis@mellanox.com>,
        David Ahern <dsahern@gmail.com>, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: [PATCH net-next] mlxsw: spectrum_router: avoid uninitialized variable access
Date:   Fri,  6 Jul 2018 14:44:45 +0200
Message-Id: <20180706124455.3151925-1-arnd@arndb.de>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

When CONFIG_BRIDGE_VLAN_FILTERING is disabled, gcc correctly points out
that the 'vid' variable is uninitialized whenever br_vlan_get_pvid
returns an error:

drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c: In function 'mlxsw_sp_rif_vlan_fid_get':
drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c:6881:6: error: 'vid' may be used uninitialized in this function [-Werror=maybe-uninitialized]

This changes the condition check to always return -EINVAL here,
which I guess is what the author intended here.

Fixes: e6f1960ae6c7 ("mlxsw: spectrum_router: Allocate FID according to PVID")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c b/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c
index 071428227b91..60c352ddd6fd 100644
--- a/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c
+++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c
@@ -6878,11 +6878,9 @@ mlxsw_sp_rif_vlan_fid_get(struct mlxsw_sp_rif *rif,
 		vid = vlan_dev_vlan_id(rif->dev);
 	} else {
 		err = br_vlan_get_pvid(rif->dev, &vid);
-		if (!vid)
-			err = -EINVAL;
-		if (err) {
+		if (err < 0 || !vid) {
 			NL_SET_ERR_MSG_MOD(extack, "Couldn't determine bridge PVID");
-			return ERR_PTR(err);
+			return ERR_PTR(-EINVAL);
 		}
 	}
 
-- 
2.9.0