Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756076AbdLPJ3Q (ORCPT ); Sat, 16 Dec 2017 04:29:16 -0500 Received: from mail-wm0-f54.google.com ([74.125.82.54]:39799 "EHLO mail-wm0-f54.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752388AbdLPJ3M (ORCPT ); Sat, 16 Dec 2017 04:29:12 -0500 X-Google-Smtp-Source: ACJfBovHb7M+s34viHXm+3BBUqU+JZcueeWWL4OHxH17WLYkRBPyWp/1/zTj+3GAYyrsdCpg9OMFtg== Subject: Re: BUG: unable to handle kernel NULL pointer dereference in fdb_find_rcu From: Nikolay Aleksandrov To: Andrei Vagin , Linux Kernel Network Developers , LKML References: <415b4093-4c58-c671-0df1-a6f650414416@cumulusnetworks.com> Message-ID: <8791c6f9-e69d-2269-f840-d8e05b0b44da@cumulusnetworks.com> Date: Sat, 16 Dec 2017 11:29:09 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.4.0 MIME-Version: 1.0 In-Reply-To: <415b4093-4c58-c671-0df1-a6f650414416@cumulusnetworks.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 810 Lines: 27 On 16/12/17 11:17, Nikolay Aleksandrov wrote: > On 16/12/17 02:37, Andrei Vagin wrote: >> Hi, >> >> We run criu tests for linux-next and today we get this bug: >> >> The kernel version is 4.15.0-rc3-next-20171215 >> >> [ 235.397328] BUG: unable to handle kernel NULL pointer dereference >> at 000000000000000c >> [ 235.398624] IP: fdb_find_rcu+0x3c/0x130 > [snip] > > Hi, > Thanks for the report, I've missed the changelink before dev creation case when I did err, s/changelink/br_stp_change_bridge_id/ the other options are set after register_netdevice, this is the only one changed before > the rhashtable conversion, some of the options do fdb lookups as part of their routine > but we don't have the table initialized yet at that point. > I'll send a fix after some testing. > > Thanks, > Nik > >