From mboxrd@z Thu Jan  1 00:00:00 1970
From: Oleg Nesterov <oleg@redhat.com>
Subject: Re: [PATCH 5/7] pid: rewrite task helper function is_global_init()
	avoiding task->pid
Date: Thu, 20 Feb 2014 19:39:58 +0100
Message-ID: <20140220183958.GB23993@redhat.com>
References: <cover.1390495874.git.rgb@redhat.com>
	<a8c13f38e0ecfa2c842f0075dbbde77f3e6befc9.1390495874.git.rgb@redhat.com>
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To: Richard Guy Briggs <rgb@redhat.com>
Cc: peterz@infradead.org, linux-kernel@vger.kernel.org, linux-audit@redhat.com, "Eric W. Biederman" <ebiederm@xmission.com>, akpm@linux-foundation.org
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On 01/23, Richard Guy Briggs wrote:
>
>  static inline int is_global_init(struct task_struct *tsk)
>  {
> -	return tsk->pid == 1;
> +	return task_pid_nr(tsk) == 1;
>  }

ACK, but we need to fix it.

With or without this change is_global_init() actually means
is-the-main-thread-of-global-init.

This is not what the callers actually want. Just look at
oom_unkillable_task(). Suppose that p is the sub-thread of
/sbin/init, if we kill this thread we kill the whole process.

The same of other callers. is_global_init() should return T
if this task is the part of init's thread group.

Oleg.