netdev - [PATCH] net: fix setting of skb->tail in skb_recycle

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Message-ID: <20081108230943.GW32552@xi.wantstofly.org>
Date:	Sun, 9 Nov 2008 00:09:43 +0100
From:	Lennert Buytenhek <buytenh@...tstofly.org>
To:	davem@...emloft.net
Cc:	netdev@...r.kernel.org, linux@...rew.com, dirk@...xia.nl
Subject: [PATCH] net: fix setting of skb->tail in skb_recycle_check()

Since skb_reset_tail_pointer() reads skb->data, we need to set
skb->data before calling skb_reset_tail_pointer().  This was causing
spurious skb_over_panic()s from skb_put() being called on a recycled
skb that had its skb->tail set to beyond where it should have been.

Bug report from Peter van Valderen <linux@...rew.com>.

Signed-off-by: Lennert Buytenhek <buytenh@...vell.com>
--
Please apply for 2.6.28, thanks!

diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 2c218a0..a17117e 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -454,8 +454,8 @@ int skb_recycle_check(struct sk_buff *skb, int skb_size)
 	shinfo->frag_list = NULL;
 
 	memset(skb, 0, offsetof(struct sk_buff, tail));
-	skb_reset_tail_pointer(skb);
 	skb->data = skb->head + NET_SKB_PAD;
+	skb_reset_tail_pointer(skb);
 
 	return 1;
 }

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