The patch titled
oom: PF_EXITING check should take mm into account
has been added to the -mm tree. Its filename is
oom-pf_exiting-check-should-take-mm-into-account.patch
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Subject: oom: PF_EXITING check should take mm into account
From: Oleg Nesterov <oleg@xxxxxxxxxx>
select_bad_process() checks PF_EXITING to detect the task which is going
to release its memory, but the logic is very wrong.
- a single process P with the dead group leader disables
select_bad_process() completely, it will always return
ERR_PTR() while P can live forever
- if the PF_EXITING task has already released its ->mm
it doesn't make sense to expect it is goiing to free
more memory (except task_struct/etc)
Change the code to ignore the PF_EXITING tasks without ->mm.
Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx>
Signed-off-by: David Rientjes <rientjes@xxxxxxxxxx>
Cc: Balbir Singh <balbir@xxxxxxxxxx>
Cc: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/oom_kill.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff -puN mm/oom_kill.c~oom-pf_exiting-check-should-take-mm-into-account mm/oom_kill.c
--- a/mm/oom_kill.c~oom-pf_exiting-check-should-take-mm-into-account
+++ a/mm/oom_kill.c
@@ -300,7 +300,7 @@ static struct task_struct *select_bad_pr
* the process of exiting and releasing its resources.
* Otherwise we could get an easy OOM deadlock.
*/
- if (p->flags & PF_EXITING) {
+ if ((p->flags & PF_EXITING) && p->mm) {
if (p != current)
return ERR_PTR(-1UL);
_
Patches currently in -mm which might be from oleg@xxxxxxxxxx are
oom-check-pf_kthread-instead-of-mm-to-skip-kthreads.patch
oom-introduce-find_lock_task_mm-to-fix-mm-false-positives.patch
oom-dump_tasks-use-find_lock_task_mm-too.patch
oom-pf_exiting-check-should-take-mm-into-account.patch
sys_personality-remove-the-bogus-checks-in-sys_personality-__set_personality-path.patch
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