From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752327AbcFEKWI (ORCPT ); Sun, 5 Jun 2016 06:22:08 -0400 Received: from wtarreau.pck.nerim.net ([62.212.114.60]:21772 "EHLO 1wt.eu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752174AbcFEKV6 (ORCPT ); Sun, 5 Jun 2016 06:21:58 -0400 From: Willy Tarreau To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Sergei Shtylyov , "David S . Miller" , Greg Kroah-Hartman , Willy Tarreau Subject: [PATCH 3.10 065/143] sh_eth: fix NULL pointer dereference in sh_eth_ring_format() Date: Sun, 5 Jun 2016 12:19:28 +0200 Message-Id: <1465122046-9645-66-git-send-email-w@1wt.eu> X-Mailer: git-send-email 2.8.0.rc2.1.gbe9624a In-Reply-To: <1465122046-9645-1-git-send-email-w@1wt.eu> References: <1465122046-9645-1-git-send-email-w@1wt.eu> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Sergei Shtylyov commit c1b7fca65070bfadca94dd53a4e6b71cd4f69715 upstream. In a low memory situation, if netdev_alloc_skb() fails on a first RX ring loop iteration in sh_eth_ring_format(), 'rxdesc' is still NULL. Avoid kernel oops by adding the 'rxdesc' check after the loop. Reported-by: Wolfram Sang Signed-off-by: Sergei Shtylyov Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman Signed-off-by: Willy Tarreau --- drivers/net/ethernet/renesas/sh_eth.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/net/ethernet/renesas/sh_eth.c b/drivers/net/ethernet/renesas/sh_eth.c index b93a0fb..93b6525 100644 --- a/drivers/net/ethernet/renesas/sh_eth.c +++ b/drivers/net/ethernet/renesas/sh_eth.c @@ -1161,7 +1161,8 @@ static void sh_eth_ring_format(struct net_device *ndev) mdp->dirty_rx = (u32) (i - mdp->num_rx_ring); /* Mark the last entry as wrapping the ring. */ - rxdesc->status |= cpu_to_edmac(mdp, RD_RDEL); + if (rxdesc) + rxdesc->status |= cpu_to_edmac(mdp, RD_RDEL); memset(mdp->tx_ring, 0, tx_ringsize); -- 2.8.0.rc2.1.gbe9624a