From mboxrd@z Thu Jan 1 00:00:00 1970 From: Neil Brown Subject: Re: Kernel 2.6.19.2 New RAID 5 Bug (oops when writing Samba -> RAID5) Date: Tue, 23 Jan 2007 08:59:36 +1100 Message-ID: <17845.13256.284461.992275@notabene.brown> References: <45B5261B.1050104@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: message from Chuck Ebbert on Monday January 22 Sender: linux-kernel-owner@vger.kernel.org To: Chuck Ebbert Cc: Justin Piszcz , linux-kernel@vger.kernel.org, linux-raid@vger.kernel.org, xfs@oss.sgi.com List-Id: linux-raid.ids On Monday January 22, cebbert@redhat.com wrote: > Justin Piszcz wrote: > > My .config is attached, please let me know if any other information is > > needed and please CC (lkml) as I am not on the list, thanks! > > > > Running Kernel 2.6.19.2 on a MD RAID5 volume. Copying files over Samba to > > the RAID5 running XFS. > > > > Any idea what happened here? .... > > > Without digging too deeply, I'd say you've hit the same bug Sami Farin > and others > have reported starting with 2.6.19: pages mapped with kmap_atomic() > become unmapped > during memcpy() or similar operations. Try disabling preempt -- that > seems to be the > common factor. That is exactly the conclusion I had just come to (a kmap_atomic page must be being unmapped during memcpy). I wasn't aware that others had reported it - thanks for that. Turning off CONFIG_PREEMPT certainly seems like a good idea. NeilBrown