Messages in this thread Patch in this message | | | Date | Wed, 2 Dec 2015 15:10:28 -0800 (PST) | From | David Rientjes <> | Subject | [patch] mm, oom: avoid attempting to kill init sharing same memory |
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From: Chen Jie <chenjie6@huawei.com>
It's possible that an oom killed victim shares an ->mm with the init process and thus oom_kill_process() would end up trying to kill init as well.
This has been shown in practice:
Out of memory: Kill process 9134 (init) score 3 or sacrifice child Killed process 9134 (init) total-vm:1868kB, anon-rss:84kB, file-rss:572kB Kill process 1 (init) sharing same memory ... Kernel panic - not syncing: Attempted to kill init! exitcode=0x00000009
And this will result in a kernel panic.
If a process is forked by init and selected for oom kill while still sharing init_mm, then it's likely this system is in a recoverable state. However, it's better not to try to kill init and allow the machine to panic due to unkillable processes.
[rientjes@google.com: rewrote changelog] Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Chen Jie <chenjie6@huawei.com> Signed-off-by: David Rientjes <rientjes@google.com> --- I removed stable from this patch since the alternative would most likely be to panic the system for no killable processes anyway. There's a very small likelihood this patch would allow for a recoverable system.
mm/oom_kill.c | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/mm/oom_kill.c b/mm/oom_kill.c --- a/mm/oom_kill.c +++ b/mm/oom_kill.c @@ -608,6 +608,8 @@ void oom_kill_process(struct oom_control *oc, struct task_struct *p, continue; if (unlikely(p->flags & PF_KTHREAD)) continue; + if (!is_global_init(p)) + continue; if (p->signal->oom_score_adj == OOM_SCORE_ADJ_MIN) continue;
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