From f6cb92d7acff81dc45586fbfc4d5bbf7eec86dcf Mon Sep 17 00:00:00 2001 From: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com> Date: Tue, 8 Mar 2016 01:36:28 +0300 Subject: [PATCH] sh_eth: fix NULL pointer dereference in sh_eth_ring_format() [ 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 <wsa+renesas@sang-engineering.com> Signed-off-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Kamal Mostafa <kamal@canonical.com> --- 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 8fd0a6b6d99f..b03d8583fb39 100644 --- a/drivers/net/ethernet/renesas/sh_eth.c +++ b/drivers/net/ethernet/renesas/sh_eth.c @@ -1168,7 +1168,8 @@ 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); -- 2.30.9