Hello,
On (06/02/16 11:21), Michal Hocko wrote:
[..]
> @@ -2863,6 +2854,7 @@ static unsigned int khugepaged_scan_mm_slot(unsigned
> int pages,
>
> collect_mm_slot(mm_slot);
> }
> + mmput(mm);
>
> return progress;
> }
this possibly sleeping mmput() is called from
under the spin_lock(&khugepaged_mm_lock).
there is also a trivial build fixup needed
(move collect_mm_slot() before __khugepaged_exit()).
it's quite hard to trigger the bug (somehow), so I can't
follow up with more information as of now.
-ss
