From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753478AbbIIScq (ORCPT ); Wed, 9 Sep 2015 14:32:46 -0400 Received: from userp1040.oracle.com ([156.151.31.81]:20801 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750819AbbIIScm (ORCPT ); Wed, 9 Sep 2015 14:32:42 -0400 Message-ID: <55F07B41.3030306@oracle.com> Date: Wed, 09 Sep 2015 14:32:33 -0400 From: Sasha Levin User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.7.0 MIME-Version: 1.0 To: Tejun Heo CC: rostedt@goodmis.org, mingo@redhat.com, axboe@fb.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH] writeback: verify that underlying dev exists before getting its name References: <1441385118-27199-1-git-send-email-sasha.levin@oracle.com> <20150904164729.GD25329@mtj.duckdns.org> <55E9D2EA.4020106@oracle.com> <20150904173650.GF25329@mtj.duckdns.org> In-Reply-To: <20150904173650.GF25329@mtj.duckdns.org> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit X-Source-IP: userv0021.oracle.com [156.151.31.71] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 09/04/2015 01:36 PM, Tejun Heo wrote: > Hello, > > On Fri, Sep 04, 2015 at 01:20:42PM -0400, Sasha Levin wrote: >>> Do you have backtrace of this happening? There's a bug in cleanup >>> path which causes oops (patch is being tested) and this may just be a >>> symptom of the same problem. >> >> [268773.335933] kasan: GPF could be caused by NULL-ptr deref or user memory accessgeneral protection fault: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC KASAN >> [268773.337986] Modules linked in: >> [268773.338470] CPU: 3 PID: 12812 Comm: trinity-c10 Not tainted 4.2.0-next-20150902-sasha-00045-gd0866f3-dirty #2528 >> [268773.339903] task: ffff8802f56e4000 ti: ffff880322e10000 task.ti: ffff880322e10000 >> [268773.340943] RIP: 0010:[] [] trace_event_raw_event_writeback_dirty_page+0x1b4/0x420 > > Hmm.... did this happen while or around a device removal event? I'm > trying to figure out whether an unregistered bdi can have inodes. I ran some more tests, and I didn't see device removal events close to it. Thanks, Sasha