From mboxrd@z Thu Jan  1 00:00:00 1970
From: Eric Dumazet <eric.dumazet@gmail.com>
Subject: Re: kernel BUG at net/core/skbuff.c:LINE! (2)
Date: Sat, 09 Dec 2017 20:51:10 -0800
Message-ID: <1512881470.25033.38.camel@gmail.com>
References: <001a1149c712d56ccc055cc48e37@google.com>
         <001a1140f5788a1817055fcfcb1f@google.com>
         <CADvbK_c5Z7rE-AABGOFKXYA5v7_XLg=V1HOGzBO1X-O13aJ8Gg@mail.gmail.com>
         <CADvbK_cnxEgU--FO+ATGL+fe2z59XVzRGzKxp1-vZxL8x8LmKA@mail.gmail.com>
         <1512838770.25033.33.camel@gmail.com>
         <CADvbK_dMfCf82LYZWeWp1EOzStwuTyjP7SzbUwa0vnT5sc38Qw@mail.gmail.com>
Mime-Version: 1.0
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: 8bit
Cc: syzbot
        <bot+ed0838d0fa4c4f2b528e20286e6dc63effc7c14d@syzkaller.appspotmail.com>,
        davem <davem@davemloft.net>, kuznet <kuznet@ms2.inr.ac.ru>,
        LKML <linux-kernel@vger.kernel.org>, linux-sctp@vger.kernel.org,
        network dev <netdev@vger.kernel.org>,
        Neil Horman <nhorman@tuxdriver.com>,
        syzkaller-bugs@googlegroups.com,
        Vlad Yasevich <vyasevich@gmail.com>,
        yoshfuji <yoshfuji@linux-ipv6.org>
To: Xin Long <lucien.xin@gmail.com>
Return-path: <netdev-owner@vger.kernel.org>
Received: from mail-pf0-f172.google.com ([209.85.192.172]:43810 "EHLO
        mail-pf0-f172.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
        with ESMTP id S1751345AbdLJEvN (ORCPT
        <rfc822;netdev@vger.kernel.org>); Sat, 9 Dec 2017 23:51:13 -0500
In-Reply-To: <CADvbK_dMfCf82LYZWeWp1EOzStwuTyjP7SzbUwa0vnT5sc38Qw@mail.gmail.com>
Sender: netdev-owner@vger.kernel.org
List-ID: <netdev.vger.kernel.org>

On Sun, 2017-12-10 at 12:36 +0800, Xin Long wrote:
> The new patch works to me, just two questions:
> 1. should it use "idev->cnf.mtu6" here for mld ?

No idea why some parts of IPv6 would use a different view of device
mtu. Maybe others can comment.

> 
> 2.  'if (int < unsigned int)' is still not nice, though in 'if
> (AVAILABLE(skb) < sizeof())'
>      AVAILABLE(skb) seems always to return >= 0 after your patch.

Really if AVAILABLE(skb) was negative, a bug already happened.