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From: Xin Xiaohui <xiaohui.xin@intel.com>
To: netdev@vger.kernel.org, herbert@gondor.apana.org.au, davem@davemloft.net
Cc: Xin Xiaohui <xiaohui.xin@intel.com>
Subject: Is it a possible bug in dev_gro_receive()?
Date: Fri, 30 Jul 2010 09:54:15 +0800	[thread overview]
Message-ID: <1280454855-7893-1-git-send-email-xiaohui.xin@intel.com> (raw)

I looked into the code dev_gro_receive(), found the code here:
if the frags[0] is pulled to 0, then the page will be released,
and memmove() frags left.
Is that right? I'm not sure if memmove do right or not, but
frags[0].size is never set after memove at least. what I think
a simple way is not to do anything if we found frags[0].size == 0.
The patch is as followed.

Or am I missing something here?

---
 net/core/dev.c |    7 -------
 1 files changed, 0 insertions(+), 7 deletions(-)

diff --git a/net/core/dev.c b/net/core/dev.c
index 264137f..28cdbbf 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -2730,13 +2730,6 @@ pull:
 
 		skb_shinfo(skb)->frags[0].page_offset += grow;
 		skb_shinfo(skb)->frags[0].size -= grow;
-
-		if (unlikely(!skb_shinfo(skb)->frags[0].size)) {
-			put_page(skb_shinfo(skb)->frags[0].page);
-			memmove(skb_shinfo(skb)->frags,
-				skb_shinfo(skb)->frags + 1,
-				--skb_shinfo(skb)->nr_frags);
-		}
 	}
 
 ok:
-- 
1.5.4.4


             reply	other threads:[~2010-07-30  1:40 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-07-30  1:54 Xin Xiaohui [this message]
2010-08-02 10:29 ` Is it a possible bug in dev_gro_receive()? Jarek Poplawski
2010-08-02 11:04   ` Herbert Xu
2010-08-03  2:33   ` Xin, Xiaohui
2010-08-03  6:45     ` Jarek Poplawski
2010-08-10  8:11       ` Xin, Xiaohui
2010-08-10  8:34         ` Jarek Poplawski
2010-08-11 12:02           ` [PATCH] net: Fix a memmove bug in dev_gro_receive() Jarek Poplawski
2010-08-18  0:37             ` David Miller

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