[PATCH 3.16 203/217] sh_eth: fix NULL pointer dereference in sh_eth_ring_format()

From	Ben Hutchings <ben@decadent.org.uk>
Newsgroups	linux.kernel
Subject	[PATCH 3.16 203/217] sh_eth: fix NULL pointer dereference in sh_eth_ring_format()
Date	2016-04-27 02:20 +0200
Message-ID	<rslmV-92-5@gated-at.bofh.it> (permalink)
References	<rskqR-7Qj-3@gated-at.bofh.it>
Organization	linux.* mail to news gateway

Show all headers | View raw

3.16.35-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>

[ 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: Ben Hutchings <ben@decadent.org.uk>
---
 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);

Back to linux.kernel | Previous | Next | Find similar | Unroll thread

Thread

[PATCH 3.16 203/217] sh_eth: fix NULL pointer dereference in   sh_eth_ring_format() Ben Hutchings <ben@decadent.org.uk> - 2016-04-27 02:20 +0200

csiph-web