From: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx>
Subject: mm, oom: fix missing tlb_finish_mmu() in __oom_reap_task_mm().
93065ac753e44438 ("mm, oom: distinguish blockable mode for mmu notifiers")
has added an ability to skip over vmas with blockable mmu notifiers. This
however didn't call tlb_finish_mmu as it should. As a result
inc_tlb_flush_pending has been called without its pairing
dec_tlb_flush_pending and all callers mm_tlb_flush_pending would flush
even though this is not really needed. This alone is not harmful and it
seems there shouldn't be any such callers for oom victims at all but there
is no real reason to skip tlb_finish_mmu on early skip either so call it.
[mhocko@xxxxxxxx: new changelog]
Link: http://lkml.kernel.org/r/b752d1d5-81ad-7a35-2394-7870641be51c@xxxxxxxxxxxxxxxxxxx
Signed-off-by: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx>
Acked-by: Michal Hocko <mhocko@xxxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/oom_kill.c | 1 +
1 file changed, 1 insertion(+)
--- a/mm/oom_kill.c~mm-oom-fix-missing-tlb_finish_mmu-in-__oom_reap_task_mm
+++ a/mm/oom_kill.c
@@ -522,6 +522,7 @@ bool __oom_reap_task_mm(struct mm_struct
tlb_gather_mmu(&tlb, mm, start, end);
if (mmu_notifier_invalidate_range_start_nonblock(mm, start, end)) {
+ tlb_finish_mmu(&tlb, start, end);
ret = false;
continue;
}
_
