netdev - Re: net/tcp: warning in tcp_try_coalesce/skb_try

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Date:   Wed, 26 Apr 2017 07:16:13 -0700
From:   Eric Dumazet <edumazet@...gle.com>
To:     Andrey Konovalov <andreyknvl@...gle.com>
Cc:     "David S. Miller" <davem@...emloft.net>,
        Alexey Kuznetsov <kuznet@....inr.ac.ru>,
        Hideaki YOSHIFUJI <yoshfuji@...ux-ipv6.org>,
        Patrick McHardy <kaber@...sh.net>,
        netdev <netdev@...r.kernel.org>,
        LKML <linux-kernel@...r.kernel.org>,
        Dmitry Vyukov <dvyukov@...gle.com>,
        Kostya Serebryany <kcc@...gle.com>,
        syzkaller <syzkaller@...glegroups.com>
Subject: Re: net/tcp: warning in tcp_try_coalesce/skb_try_coalesce

On Wed, Apr 26, 2017 at 5:08 AM, Andrey Konovalov <andreyknvl@...gle.com> wrote:
> On Tue, Jan 31, 2017 at 2:17 PM, Andrey Konovalov <andreyknvl@...gle.com> wrote:
>> Hi,
>>
>> I've got the following error report while running the syzkaller fuzzer.
>>
>> On commit 566cf877a1fcb6d6dc0126b076aad062054c2637 (4.10-rc6).
>>
>> The fuzzer hits this issue quite often, but I don't have a working reproducer.
>
> I still see this on 5a7ad1146caa895ad718a534399e38bd2ba721b7 (4.11-rc8).
>
> I also have a reproducer now, attached.
>
> It takes around 10 seconds for the warning to trigger.
>

It does not trigger for me, but seeing that you use SO_ATTACH_FILTER,
I have a pretty good idea how to remove this splat.

A call to skb_condense() from ___pskb_trim() will likely help, I will
post a patch after my commute.

Thanks.