lkml.org 
[lkml]   [2007]   [Jan]   [22]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: Kernel 2.6.19.2 New RAID 5 Bug (oops when writing Samba -> RAID5)
On 1/22/07, Neil Brown <neilb@suse.de> wrote:
> 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.
>
Coming from an ARM background I am not yet versed in the inner
workings of kmap_atomic, but if you have time for a question I am
curious as to why spin_lock(&sh->lock) is not sufficient pre-emption
protection for copy_data() in this case?

> NeilBrown

Regards,
Dan
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2007-01-23 03:37    [W:0.297 / U:1.004 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site