On 03/11/2016 12:32 PM, Vlastimil Babka wrote:

On 02/29/2016 02:26 PM, Michal Hocko wrote:

quoted

From: Michal Hocko <mhocko@suse.com>

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@redhat.com>
Signed-off-by: Michal Hocko <mhocko@suse.com>

Acked-by: Vlastimil Babka <redacted>

Forgot to point out typo in Subject which makes it hard to grep for mmap_sem