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

[Vlastimil Babka]

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