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Date: Thu, 6 Dec 2007 20:01:45 +0300
From: Oleg Nesterov <oleg@tv-sign.ru>
To: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Andrew Morton <akpm@linux-foundation.org>, linux-kernel@vger.kernel.org,
       Linux Containers <containers@lists.osdl.org>,
       Pavel Emelyanov <xemul@openvz.org>, sukadev@us.ibm.com
Subject: Re: [PATCH] pid: sys_wait... fixes
Message-ID: <20071206170145.GA10674@tv-sign.ru>
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On 12/05, Eric W. Biederman wrote:
> 
> This modifies do_wait and eligible_child to take a pair of
> enum pid_type and struct pid *pid to precisely specify what
> set of processes are eligible to be waited for,  instead of the
> raw pid_t value from sys_wait4.

Personally, I like this patch very much. Not only it fixes the bug,
in my opinion it also makes the code more clean.

However at first glance it has a minor fixable problem,

> +	if (type < PIDTYPE_MAX) {
> +		if (p->pids[type].pid != pid)
>  			return 0;
>  	}

If type != PIDTYPE_PID we can't trust p->pids[type].pid unless p is a
group leader. This .pid could be just a "random value".

Oleg.