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Date: Thu, 21 May 2009 16:35:53 +0200
Message-ID: <8763fuwmk6.wl%vmayatsk@redhat.com>
From: Vitaly Mayatskikh <v.mayatskih@gmail.com>
To: Oleg Nesterov <oleg@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>, Vitaly Mayatskikh <v.mayatskih@gmail.com>,
       Andrew Morton <akpm@linux-foundation.org>,
       Roland McGrath <roland@redhat.com>, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/5] Split wait_noreap_copyout()
In-Reply-To: <20090521141250.GC14149@redhat.com>
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At Thu, 21 May 2009 16:12:50 +0200, Oleg Nesterov wrote:

> Roland thinks that "-EFAULT -> success" change is acceptable, and I think
> the same. So, to me the best option is just  change the changelog of this
> patch and that is all.
> 
> Or. We can make a trivial patch which adds the behavior change first:
> 
> 	Changelog: always accept the NULL infop, because it is not
> 	possible to understand the current behaviour ;)
> 
> 	User-visible change! needs Acks!
> 
> 	--- a/kernel/exit.c
> 	+++ b/kernel/exit.c
> 	@@ -1126,24 +1126,26 @@ static int eligible_child(struct wait_op
> 	 static int wait_noreap_copyout(struct wait_opts *wo, struct task_struct *p,
> 					pid_t pid, uid_t uid, int why, int status)
> 	 {
> 	-	struct siginfo __user *infop;
> 		int retval = wo->wo_rusage
> 			? getrusage(p, RUSAGE_BOTH, wo->wo_rusage) : 0;
> 	-
> 		put_task_struct(p);
> 	-	infop = wo->wo_info;
> 	-	if (!retval)
> 	-		retval = put_user(SIGCHLD, &infop->si_signo);
> 	-	if (!retval)
> 	-		retval = put_user(0, &infop->si_errno);
> 	-	if (!retval)
> 	-		retval = put_user((short)why, &infop->si_code);
> 	-	if (!retval)
> 	-		retval = put_user(pid, &infop->si_pid);
> 	-	if (!retval)
> 	-		retval = put_user(uid, &infop->si_uid);
> 	-	if (!retval)
> 	-		retval = put_user(status, &infop->si_status);
> 	+
> 	+	if (wo->wo_info) {
> 	+		struct siginfo __user *infop = wo->wo_info;
> 	+
> 	+		if (!retval)
> 	+			retval = put_user(SIGCHLD, &infop->si_signo);
> 	+		if (!retval)
> 	+			retval = put_user(0, &infop->si_errno);
> 	+		if (!retval)
> 	+			retval = put_user((short)why, &infop->si_code);
> 	+		if (!retval)
> 	+			retval = put_user(pid, &infop->si_pid);
> 	+		if (!retval)
> 	+			retval = put_user(uid, &infop->si_uid);
> 	+		if (!retval)
> 	+			retval = put_user(status, &infop->si_status);
> 	+	}
> 		if (!retval)
> 			retval = pid;
> 		return retval;
> 
> And then redo Vitaly's patches on top of this change.
> 
> What do you and Vitaly think?

I like your idea.

-- 
wbr, Vitaly