From: Marc Zyngier <marc.zyngier@arm.com>
Date: Tue, 5 Aug 2014 15:44:39 +0000 (+0100)
Subject: net: sun4i-emac: fix memory leak on bad packet
X-Git-Tag: v3.17-rc1~106^2^2~1
X-Git-Url: http://git.samba.org/samba.git/?a=commitdiff_plain;h=2670cc699a66c4cf268cb3e3f6dfc325ec14f224;p=sfrench%2Fcifs-2.6.git

net: sun4i-emac: fix memory leak on bad packet

Upon reception of a new frame, the emac driver checks for a number
of error conditions, and flag the packet as "bad" if any of these
are present. It then allocates a skb unconditionally, but only uses
it if the packet is "good". On the error path, the skb is just forgotten,
and the system leaks memory.

The piece of junk I have on my desk seems to encounter such error
frequently enough so that the box goes OOM after a couple of days,
which makes me grumpy.

Fix this by moving the allocation on the "good_packet" path (and
convert it to netdev_alloc_skb while we're at it).

Tested on a random Allwinner A20 board.

Cc: Stefan Roese <sr@denx.de>
Cc: Maxime Ripard <maxime.ripard@free-electrons.com>
Cc: <stable@vger.kernel.org> # 3.11+
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Acked-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---

diff --git a/drivers/net/ethernet/allwinner/sun4i-emac.c b/drivers/net/ethernet/allwinner/sun4i-emac.c
index d81e7167a8b5..29b9f082475d 100644
--- a/drivers/net/ethernet/allwinner/sun4i-emac.c
+++ b/drivers/net/ethernet/allwinner/sun4i-emac.c
@@ -633,8 +633,10 @@ static void emac_rx(struct net_device *dev)
 		}
 
 		/* Move data from EMAC */
-		skb = dev_alloc_skb(rxlen + 4);
-		if (good_packet && skb) {
+		if (good_packet) {
+			skb = netdev_alloc_skb(dev, rxlen + 4);
+			if (!skb)
+				continue;
 			skb_reserve(skb, 2);
 			rdptr = (u8 *) skb_put(skb, rxlen - 4);