[PATCH] mm: sync rss-counters at the end of exit_mm()

From: Konstantin Khlebnikov
Date: Mon Apr 09 2012 - 16:03:38 EST


On task's exit do_exit() calls sync_mm_rss() but this is not enough,
there can be page-faults after this point, for example exit_mm() ->
mm_release() -> put_user() (for processing tsk->clear_child_tid).
Thus there may be some rss-counters delta in current->rss_stat.

Signed-off-by: Konstantin Khlebnikov <khlebnikov@xxxxxxxxxx>
Reported-by: Markus Trippelsdorf <markus@xxxxxxxxxxxxxxx>
Cc: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
---
kernel/exit.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/kernel/exit.c b/kernel/exit.c
index d8bd3b42..8e09dbe 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -683,6 +683,7 @@ static void exit_mm(struct task_struct * tsk)
enter_lazy_tlb(mm, current);
task_unlock(tsk);
mm_update_next_owner(mm);
+ sync_mm_rss(mm);
mmput(mm);
}


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