On 1/22/07, Neil Brown <[EMAIL PROTECTED]> wrote:
On Monday January 22, [EMAIL PROTECTED] 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
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