tree 7ce86f8702cdf9ad93ad37064654fa21a43f411b
parent 137d1a26c842a384c98dd2a6a605014fddf5c777
author Anton Vorontsov <anton.vorontsov@linaro.org> 1338506786 -0700
committer Linus Torvalds <torvalds@linux-foundation.org> 1338511770 -0700

um: properly check all process' threads for a live mm

kill_off_processes() might miss a valid process, this is because checking
for process->mm is not enough.  Process' main thread may exit or detach
its mm via use_mm(), but other threads may still have a valid mm.

To catch this we use find_lock_task_mm(), which walks up all threads and
returns an appropriate task (with task lock held).

Suggested-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Anton Vorontsov <anton.vorontsov@linaro.org>
Cc: Richard Weinberger <richard@nod.at>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>