linux-kernel - [PATCH][next] dpaa2-mac: Fix potential null pointer dereference

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Message-ID: <20200925170323.GA20546@embeddedor>
Date:   Fri, 25 Sep 2020 12:03:23 -0500
From:   "Gustavo A. R. Silva" <gustavoars@...nel.org>
To:     Ioana Ciornei <ioana.ciornei@....com>,
        Ioana Radulescu <ruxandra.radulescu@....com>,
        "David S. Miller" <davem@...emloft.net>,
        Jakub Kicinski <kuba@...nel.org>, Andrew Lunn <andrew@...n.ch>
Cc:     netdev@...r.kernel.org, linux-kernel@...r.kernel.org,
        "Gustavo A. R. Silva" <gustavoars@...nel.org>
Subject: [PATCH][next] dpaa2-mac: Fix potential null pointer dereference

There is a null-check for _pcs_, but it is being dereferenced
prior to this null-check. So, if _pcs_ can actually be null,
then there is a potential null pointer dereference that should
be fixed by null-checking _pcs_ before being dereferenced.

Addresses-Coverity-ID: 1497159 ("Dereference before null check")
Fixes: 94ae899b2096 ("dpaa2-mac: add PCS support through the Lynx module")
Signed-off-by: Gustavo A. R. Silva <gustavoars@...nel.org>
---
 drivers/net/ethernet/freescale/dpaa2/dpaa2-mac.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/freescale/dpaa2/dpaa2-mac.c b/drivers/net/ethernet/freescale/dpaa2/dpaa2-mac.c
index 6ff64dd1cf27..283c5b1dbaad 100644
--- a/drivers/net/ethernet/freescale/dpaa2/dpaa2-mac.c
+++ b/drivers/net/ethernet/freescale/dpaa2/dpaa2-mac.c
@@ -291,9 +291,9 @@ static int dpaa2_pcs_create(struct dpaa2_mac *mac,
 static void dpaa2_pcs_destroy(struct dpaa2_mac *mac)
 {
 	struct lynx_pcs *pcs = mac->pcs;
-	struct device *dev = &pcs->mdio->dev;
 
 	if (pcs) {
+		struct device *dev = &pcs->mdio->dev;
 		lynx_pcs_destroy(pcs);
 		put_device(dev);
 		mac->pcs = NULL;
-- 
2.27.0