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Date: Sun, 29 Nov 2015 19:08:02 -0800
From: Andrew Morton <akpm@linux-foundation.org>
To: <chenjie6@huawei.com>
Cc: <linux-mm@kvack.org>, <linux-kernel@vger.kernel.org>,
        <David.Woodhouse@intel.com>, <zhihui.gao@huawei.com>,
        <lizefan@huawei.com>, <stable@vger.kernel.org>
Subject: Re: [PATCH] bugfix oom kill init lead panic
Message-Id: <20151129190802.dc66cf35.akpm@linux-foundation.org>
In-Reply-To: <1448880869-20506-1-git-send-email-chenjie6@huawei.com>
References: <1448880869-20506-1-git-send-email-chenjie6@huawei.com>
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On Mon, 30 Nov 2015 18:54:29 +0800 <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.
> 
> ...
>
> --- a/mm/oom_kill.c
> +++ b/mm/oom_kill.c
> @@ -513,7 +513,7 @@ void oom_kill_process(struct task_struct *p, gfp_t gfp_mask, int order,
>  	rcu_read_lock();
>  	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;

What kernel version are you using?

I don't think this can happen in current code...