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Date: Mon, 15 Jun 2009 18:55:36 +0200
From: Oleg Nesterov <oleg@redhat.com>
To: Vitaly Mayatskikh <v.mayatskih@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>, Ingo Molnar <mingo@elte.hu>,
       Roland McGrath <roland@redhat.com>, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 5/5] Use copy_wait_opts_to_user() in
	wait_task_continued()
Message-ID: <20090615165536.GC7425@redhat.com>
References: <1242048349-2766-1-git-send-email-v.mayatskih@gmail.com> <1242048349-2766-6-git-send-email-v.mayatskih@gmail.com>
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On 05/11, Vitaly Mayatskikh wrote:
>
> --- a/kernel/exit.c
> +++ b/kernel/exit.c
> @@ -1416,19 +1416,16 @@ static int wait_task_continued(struct wait_opts *wo, struct task_struct *p)
>  	get_task_struct(p);
>  	read_unlock(&tasklist_lock);
>
> -	if (!wo->wo_info) {
> -		retval = wo->wo_rusage
> -			? getrusage(p, RUSAGE_BOTH, wo->wo_rusage) : 0;
> -		put_task_struct(p);
> -		if (!retval && wo->wo_stat)
> -			retval = put_user(0xffff, wo->wo_stat);
> -		if (!retval)
> -			retval = pid;
> -	} else {
> -		retval = wait_noreap_copyout(wo, p, pid, uid,
> -					     CLD_CONTINUED, SIGCONT);
> -		BUG_ON(retval == 0);
> -	}
> +	retval = copy_wait_opts_to_user(wo, p, pid, uid,
> +					CLD_CONTINUED, SIGCONT, SIGCHLD);
> +	put_task_struct(p);
> +
> +	if (!retval && wo->wo_stat)
> +		retval = put_user(0xffff, wo->wo_stat);

This adds another user-visible change. Before the patch, we ignore
->wo_stat if ->wo_info != NULL.

This change looks like the fix to me, but again, this should be
documented/discussed.


I could send the fixes for 3 and 4, but unfortunately Vitaly has
the vacation now. I think it is better to drop

	wait_task_-cleanups-split-wait_noreap_copyout.patch
	wait_task_-cleanups-use-copy_wait_opts_to_user-in-wait_task_stopped.patch
	wait_task_-cleanups-use-copy_wait_opts_to_user-in-do_wait.patch
	wait_task_-cleanups-use-copy_wait_opts_to_user-in-wait_task_zombie.patch
	wait_task_-cleanups-use-copy_wait_opts_to_user-in-wait_task_continued.patch

patches, and wait for Vitaly to redo/resend.

Oleg.