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| author | Oleg Nesterov <oleg@redhat.com> | 2011-07-30 16:35:02 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2011-08-03 12:42:51 -0700 |
| commit | 64b1641d7c7b9a65619522a11ce4abe9b8fd2d9c (patch) | |
| tree | e1c654ed7e27649b7d0152d8ad02115175b92554 | |
| parent | 95df2d8860b2fd0759722fe691c244f0769829c6 (diff) | |
| download | linux-rt-64b1641d7c7b9a65619522a11ce4abe9b8fd2d9c.tar.gz | |
oom: task->mm == NULL doesn't mean the memory was freed
commit c027a474a68065391c8773f6e83ed5412657e369 upstream.
exit_mm() sets ->mm == NULL then it does mmput()->exit_mmap() which
frees the memory.
However select_bad_process() checks ->mm != NULL before TIF_MEMDIE,
so it continues to kill other tasks even if we have the oom-killed
task freeing its memory.
Change select_bad_process() to check ->mm after TIF_MEMDIE, but skip
the tasks which have already passed exit_notify() to ensure a zombie
with TIF_MEMDIE set can't block oom-killer. Alternatively we could
probably clear TIF_MEMDIE after exit_mmap().
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
| -rw-r--r-- | mm/oom_kill.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/mm/oom_kill.c b/mm/oom_kill.c index f52e85c80e8d..5299cb8756ff 100644 --- a/mm/oom_kill.c +++ b/mm/oom_kill.c @@ -285,7 +285,7 @@ static struct task_struct *select_bad_process(unsigned int *ppoints, do_each_thread(g, p) { unsigned int points; - if (!p->mm) + if (p->exit_state) continue; if (oom_unkillable_task(p, mem, nodemask)) continue; @@ -301,6 +301,8 @@ static struct task_struct *select_bad_process(unsigned int *ppoints, */ if (test_tsk_thread_flag(p, TIF_MEMDIE)) return ERR_PTR(-1UL); + if (!p->mm) + continue; if (p->flags & PF_EXITING) { /* |