Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754943AbcD0AO0 (ORCPT ); Tue, 26 Apr 2016 20:14:26 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:40031 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753974AbcDZXN6 (ORCPT ); Tue, 26 Apr 2016 19:13:58 -0400 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Wolfram Sang" , "Sergei Shtylyov" , "David S. Miller" Date: Wed, 27 Apr 2016 01:02:21 +0200 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.16 203/217] sh_eth: fix NULL pointer dereference in sh_eth_ring_format() In-Reply-To: X-SA-Exim-Connect-IP: 2a02:8426:ae4:c500:9cba:69ae:962d:6167 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1163 Lines: 32 3.16.35-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Sergei Shtylyov [ Upstream commit c1b7fca65070bfadca94dd53a4e6b71cd4f69715 ] 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: Ben Hutchings --- drivers/net/ethernet/renesas/sh_eth.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/drivers/net/ethernet/renesas/sh_eth.c +++ b/drivers/net/ethernet/renesas/sh_eth.c @@ -1162,7 +1162,8 @@ static void sh_eth_ring_format(struct ne 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);