Subject: + oom-avoid-killing-init-if-it-assumed-the-oom-killed-threads-mm.patch added to -mm tree
To: ming.liu@xxxxxxxxxxxxx,rientjes@xxxxxxxxxx
From: akpm@xxxxxxxxxxxxxxxxxxxx
Date: Tue, 24 Sep 2013 16:48:23 -0700
The patch titled
Subject: oom: avoid killing init if it assumed the oom killed thread's mm
has been added to the -mm tree. Its filename is
oom-avoid-killing-init-if-it-assumed-the-oom-killed-threads-mm.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/oom-avoid-killing-init-if-it-assumed-the-oom-killed-threads-mm.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/oom-avoid-killing-init-if-it-assumed-the-oom-killed-threads-mm.patch
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------------------------------------------------------
From: Ming Liu <ming.liu@xxxxxxxxxxxxx>
Subject: oom: avoid killing init if it assumed the oom killed thread's mm
After selecting a task to kill, the oom killer iterates all processes and
kills all other user threads that share the same mm_struct in different
thread groups.
But in some extreme cases, the selected task happens to be a vfork child
of init process sharing the same mm_struct with it, which causes kernel
panic on init getting killed. This panic is observed in a busybox shell
that busybox itself is init, when a kthread keeps consuming memory.
Signed-off-by: Ming Liu <ming.liu@xxxxxxxxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/oom_kill.c | 16 ++++++++--------
1 file changed, 8 insertions(+), 8 deletions(-)
diff -puN mm/oom_kill.c~oom-avoid-killing-init-if-it-assumed-the-oom-killed-threads-mm mm/oom_kill.c
--- a/mm/oom_kill.c~oom-avoid-killing-init-if-it-assumed-the-oom-killed-threads-mm
+++ a/mm/oom_kill.c
@@ -479,17 +479,17 @@ void oom_kill_process(struct task_struct
task_unlock(victim);
/*
- * Kill all user processes sharing victim->mm in other thread groups, if
- * any. They don't get access to memory reserves, though, to avoid
- * depletion of all memory. This prevents mm->mmap_sem livelock when an
- * oom killed thread cannot exit because it requires the semaphore and
- * its contended by another thread trying to allocate memory itself.
- * That thread will now get access to memory reserves since it has a
- * pending fatal signal.
+ * Kill all user processes except init sharing victim->mm in other
+ * thread groups, if any. They don't get access to memory reserves,
+ * though, to avoid depletion of all memory. This prevents mm->mmap_sem
+ * livelock when an oom killed thread cannot exit because it requires
+ * the semaphore and its contended by another thread trying to allocate
+ * memory itself. That thread will now get access to memory reserves
+ * since it has a pending fatal signal.
*/
for_each_process(p)
if (p->mm == mm && !same_thread_group(p, victim) &&
- !(p->flags & PF_KTHREAD)) {
+ !(p->flags & PF_KTHREAD) && !is_global_init(p)) {
if (p->signal->oom_score_adj == OOM_SCORE_ADJ_MIN)
continue;
_
Patches currently in -mm which might be from ming.liu@xxxxxxxxxxxxx are
oom-avoid-killing-init-if-it-assumed-the-oom-killed-threads-mm.patch
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