netdev - [PATCH] net: pktgen: fix null ptr deref in skb allocation

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Date:	Sun, 10 Jan 2016 21:38:44 -0800
From:	John Fastabend <john.fastabend@...il.com>
To:	netdev@...r.kernel.org
Cc:	bogdan.hamciuc@...escale.com, davem@...emloft.net
Subject: [PATCH] net: pktgen: fix null ptr deref in skb allocation

Fix possible null pointer dereference that may occur when calling
skb_reserve() on a null skb.

Fixes: 879c7220e82 ("net: pktgen: Observe needed_headroom of the device")
Signed-off-by: John Fastabend <john.r.fastabend@...el.com>
---
 net/core/pktgen.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/net/core/pktgen.c b/net/core/pktgen.c
index de8d5cc..4da4d51 100644
--- a/net/core/pktgen.c
+++ b/net/core/pktgen.c
@@ -2787,7 +2787,9 @@ static struct sk_buff *pktgen_alloc_skb(struct net_device *dev,
 	} else {
 		 skb = __netdev_alloc_skb(dev, size, GFP_NOWAIT);
 	}
-	skb_reserve(skb, LL_RESERVED_SPACE(dev));
+
+	if (likely(skb))
+		skb_reserve(skb, LL_RESERVED_SPACE(dev));
 
 	return skb;
 }