From mboxrd@z Thu Jan 1 00:00:00 1970 From: Matthias Ferdinand Subject: Re: md-raid5 with bcache member devices => kernel panic Date: Fri, 6 Dec 2013 00:08:13 +0100 Message-ID: <20131205230813.GF1848@teapot> References: <20131205212913.GE1848@teapot> <20131205225234.GA4054@kmo> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Return-path: Received: from sw.mfedv.net ([212.82.36.162]:41252 "EHLO sw.mfedv.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751699Ab3LEXIX (ORCPT ); Thu, 5 Dec 2013 18:08:23 -0500 Content-Disposition: inline In-Reply-To: <20131205225234.GA4054@kmo> Sender: linux-bcache-owner@vger.kernel.org List-Id: linux-bcache@vger.kernel.org To: Kent Overstreet Cc: nks@daterainc.com, linux-bcache@vger.kernel.org On Thu, Dec 05, 2013 at 02:52:34PM -0800, Kent Overstreet wrote: > On Thu, Dec 05, 2013 at 10:29:13PM +0100, Matthias Ferdinand wrote: > Erk. I thought I was done with these bugs. Nick, do you think you could try and > track this down? > > Looking at this: > http://dl.mfedv.net/md5raid_on_bcache_panic/mdraid5_on_bcache_panic_3.12.2.txt > > that's a null pointer deref; if Matthias could get the exact line number it I have no idea how to do that - can you help me out on that? > Matthias - I'm running bcache on top of a raid6 at home and I've never seen I only get panics when I use md-raid on top of bcaches: LVM | md-raid5 / | \ bcache0 bcache1 bcache2 | | | sdb6 sdc6 sdd6 (probably an unusual setup; just playing around...) To reproduce, just writing anything to an LV on top of this should do (linear writes). If some r/w random i/o is then added (start of VM in my setup), it breaks. Regards Matthias