From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Wolfram Sang , Sergei Shtylyov , "David S. Miller" Subject: [PATCH 4.4 047/137] sh_eth: fix NULL pointer dereference in sh_eth_ring_format() Date: Mon, 18 Apr 2016 11:28:29 +0900 Message-Id: <20160418022510.335374753@linuxfoundation.org> In-Reply-To: <20160418022507.236379264@linuxfoundation.org> References: <20160418022507.236379264@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 Sender: linux-kernel-owner@vger.kernel.org List-ID: 4.4-stable 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: Greg Kroah-Hartman --- 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 @@ -1212,7 +1212,8 @@ 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_RDLE); + if (rxdesc) + rxdesc->status |= cpu_to_edmac(mdp, RD_RDLE); memset(mdp->tx_ring, 0, tx_ringsize);