oom: multi threaded process coredump don't make deadlock
cef1d352 · KOSAKI Motohiro <[email protected]> · 2010-08-09 17:19:42 -07:00
Oleg pointed out current PF_EXITING check is wrong. Because PF_EXITING
is per-thread flag, not per-process flag. He said,
Two threads, group-leader L and its sub-thread T. T dumps the code.
In this case both threads have ->mm != NULL, L has PF_EXITING.
The first problem is, select_bad_process() always return -1 in this
case (even if the caller is T, this doesn't matter).
The second problem is that we should add TIF_MEMDIE to T, not L.
I think we can remove this dubious PF_EXITING check. but as first step,
This patch add the protection of multi threaded issue.
Signed-off-by: KOSAKI Motohiro <[email protected]>
Cc: Oleg Nesterov <[email protected]>
Cc: Minchan Kim <[email protected]>
Cc: David Rientjes <[email protected]>
Cc: KAMEZAWA Hiroyuki <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
- Commit
- cef1d3523d33ebc35fc29e454b1f4bab953fabbf
- Parents
- 93b43fa5
Changes
1 files changed · +1 −1
diff --git a/mm/oom_kill.c b/mm/oom_kill.c
index 31bd0c3..0a4ca8a 100644
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -360,7 +360,7 @@ static struct task_struct *select_bad_process(unsigned long *ppoints,
* the process of exiting and releasing its resources.
* Otherwise we could get an easy OOM deadlock.
*/
- if ((p->flags & PF_EXITING) && p->mm) {
+ if (thread_group_empty(p) && (p->flags & PF_EXITING) && p->mm) {
if (p != current)
return ERR_PTR(-1UL);