[PATCH 4.4 047/137] sh_eth: fix NULL pointer dereference in sh_eth_ring_format()
From: Greg Kroah-Hartman
Date: Sun Apr 17 2016 - 22:56:44 EST
4.4-stable review patch. If anyone has any objections, please let me know.
------------------
From: Sergei Shtylyov <sergei.shtylyov@xxxxxxxxxxxxxxxxxx>
[ 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@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Sergei Shtylyov <sergei.shtylyov@xxxxxxxxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
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);