[PATCH] oom kill init lead panic

[PATCH] oom kill init lead panic

[chenjie6]

From: chenjie <chenjie6@huawei.com>

when oom happened we can see:
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

That's because:
        the busybox init will vfork a process,oom_kill_process found
the init not the children,their mm is the same when vfork.

Cc: <stable@vger.kernel.org>
Signed-off-by: Chen Jie <chenjie6@huawei.com>

---
 mm/oom_kill.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/mm/oom_kill.c b/mm/oom_kill.c
index d13a339..a0ddebd 100644
--- 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;
 
-- 
1.8.0

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Re: [PATCH] oom kill init lead panic

[Michal Hocko]

On Wed 02-12-15 14:30:56, chenjie6@huawei.com wrote:
> From: chenjie <chenjie6@huawei.com>
> 
> when oom happened we can see:
> 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
> 
> That's because:
>         the busybox init will vfork a process,oom_kill_process found
> the init not the children,their mm is the same when vfork.

It is quite unlikely that killing the task would help to free much
memory so if this is really the only oom victim it is to be expected to
panic sooner or later but this is in line with oom_unkillable_task()
so it makes sense.
 
> Cc: <stable@vger.kernel.org>
> Signed-off-by: Chen Jie <chenjie6@huawei.com>

Acked-by: Michal Hocko <mhocko@suse.com>

> 
> ---
>  mm/oom_kill.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/mm/oom_kill.c b/mm/oom_kill.c
> index d13a339..a0ddebd 100644
> --- 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;
>  
> -- 
> 1.8.0
> 
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-- 
Michal Hocko
SUSE Labs

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Re: [PATCH] oom kill init lead panic

[Greg KH]

On Wed, Dec 02, 2015 at 02:30:56PM +0800, chenjie6@huawei.com wrote:
> From: chenjie <chenjie6@huawei.com>

This name should match...

> Signed-off-by: Chen Jie <chenjie6@huawei.com>

this name please.

thanks,

greg k-h

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