From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760567AbbIDQrf (ORCPT ); Fri, 4 Sep 2015 12:47:35 -0400 Received: from mail-yk0-f174.google.com ([209.85.160.174]:35374 "EHLO mail-yk0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1760550AbbIDQrc (ORCPT ); Fri, 4 Sep 2015 12:47:32 -0400 Date: Fri, 4 Sep 2015 12:47:29 -0400 From: Tejun Heo To: Sasha Levin 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 Message-ID: <20150904164729.GD25329@mtj.duckdns.org> References: <1441385118-27199-1-git-send-email-sasha.levin@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1441385118-27199-1-git-send-email-sasha.levin@oracle.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Sep 04, 2015 at 12:45:18PM -0400, Sasha Levin wrote: > We can't assume there is always an underlying device and must verify that > as well. Otherwise, we'd deref a NULL ptr here. 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. Thanks. -- tejun