Re: [PATCH v3] ip: fix truesize mismatch in ip fragmentation

[David Miller]

From: Jarek Poplawski <jarkao2@xxxxxxxxx>
Date: Tue, 21 Sep 2010 21:21:54 +0200

> On Tue, Sep 21, 2010 at 08:47:45PM +0200, Eric Dumazet wrote:
>> [PATCH v4] ip: fix truesize mismatch in ip fragmentation
>> 
>> Special care should be taken when slow path is hit in ip_fragment() :
>> 
>> When walking through frags, we transfert truesize ownership from skb to
>> frags. Then if we hit a slow_path condition, we must undo this or risk
>> uncharging frags->truesize twice, and in the end, having negative socket
>> sk_wmem_alloc counter, or even freeing socket sooner than expected.
>> 
>> Many thanks to Nick Bowler, who provided a very clean bug report and
>> test program.
>> 
>> Thanks to Jarek for reviewing my first patch and providing a V2
>> 
>> While Nick bisection pointed to commit 2b85a34e911 (net: No more
>> expensive sock_hold()/sock_put() on each tx), underlying bug is older
>> (2.6.12-rc5)
>> 
>> A side effect is to extend work done in commit b2722b1c3a893e
>> (ip_fragment: also adjust skb->truesize for packets not owned by a
>> socket) to ipv6 as well.
>> 
>> Reported-and-bisected-by: Nick Bowler <nbowler@xxxxxxxxxxxxxxxx>
>> Tested-by: Nick Bowler <nbowler@xxxxxxxxxxxxxxxx>
>> Signed-off-by: Eric Dumazet <eric.dumazet@xxxxxxxxx>
>> CC: Jarek Poplawski <jarkao2@xxxxxxxxx>
>> CC: Patrick McHardy <kaber@xxxxxxxxx>
> 
> Looks perfect to me.

Great work everyone!

Applied, thanks.
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