From: David Miller <davem@davemloft.net>
To: andreyknvl@google.com
Cc: eric.dumazet@gmail.com, netdev@vger.kernel.org
Subject: Re: [PATCH net] tcp: do not underestimate skb->truesize in tcp_trim_head()
Date: Fri, 28 Apr 2017 16:05:56 -0400 (EDT) [thread overview]
Message-ID: <20170428.160556.2072008893563794166.davem@davemloft.net> (raw)
In-Reply-To: <CAAeHK+xWDnPu05g4Hqt3wkHEsuW=Ry7p7rLnxL3ct1MuSLBXLw@mail.gmail.com>
From: Andrey Konovalov <andreyknvl@google.com>
Date: Thu, 27 Apr 2017 13:49:57 +0200
> On Thu, Apr 27, 2017 at 2:15 AM, Eric Dumazet <eric.dumazet@gmail.com> wrote:
>> From: Eric Dumazet <edumazet@google.com>
>>
>> Andrey found a way to trigger the WARN_ON_ONCE(delta < len) in
>> skb_try_coalesce() using syzkaller and a filter attached to a TCP
>> socket over loopback interface.
>>
>> I believe one issue with looped skbs is that tcp_trim_head() can end up
>> producing skb with under estimated truesize.
>>
>> It hardly matters for normal conditions, since packets sent over
>> loopback are never truncated.
>>
>> Bytes trimmed from skb->head should not change skb truesize, since
>> skb->head is not reallocated.
>
> Hi Eric,
>
> With all 3 of your patches applied to net-next I don't see the warning any more.
>
> Thanks!
>
> Tested-by: Andrey Konovalov <andreyknvl@google.com>
Applied and queued up for -stable, thanks Eric.
next prev parent reply other threads:[~2017-04-28 20:05 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-04-26 16:07 [PATCH net] net: adjust skb->truesize in ___pskb_trim() Eric Dumazet
2017-04-26 17:08 ` Andrey Konovalov
2017-04-27 18:43 ` Willem de Bruijn
2017-04-27 0:15 ` [PATCH net] tcp: do not underestimate skb->truesize in tcp_trim_head() Eric Dumazet
2017-04-27 11:49 ` Andrey Konovalov
2017-04-28 20:05 ` David Miller [this message]
2017-04-28 20:07 ` [PATCH net] net: adjust skb->truesize in ___pskb_trim() David Miller
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