Re: [PATCH 11/18] coredump: make coredump_wait wait for mma_sem for write killable

[Michal Hocko]

On Fri 11-03-16 12:54:17, Vlastimil Babka wrote:
> On 03/11/2016 12:32 PM, Vlastimil Babka wrote:
> >On 02/29/2016 02:26 PM, Michal Hocko wrote:
> >>From: Michal Hocko <mhocko@xxxxxxxx>
> >>
> >>coredump_wait waits for mmap_sem for write currently which can
> >>prevent oom_reaper to reclaim the oom victims address space
> >>asynchronously because that requires mmap_sem for read. This might
> >>happen if the oom victim is multi threaded and some thread(s) is
> >>holding mmap_sem for read (e.g. page fault) and it is stuck in
> >>the page allocator while other thread(s) reached coredump_wait
> >>already.
> >>
> >>This patch simply uses down_write_killable and bails out with EINTR
> >>if the lock got interrupted by the fatal signal. do_coredump will
> >>return right away and do_group_exit will take care to zap the whole
> >>thread group.
> >>
> >>Cc: Oleg Nesterov <oleg@xxxxxxxxxx>
> >>Signed-off-by: Michal Hocko <mhocko@xxxxxxxx>
> >
> >Acked-by: Vlastimil Babka <vbabka@xxxxxxx>
> 
> Forgot to point out typo in Subject which makes it hard to grep for mmap_sem

Fixed and thanks!

-- 
Michal Hocko
SUSE Labs