From owner-freebsd-threads@FreeBSD.ORG  Thu Feb 19 05:48:15 2004
Return-Path: <owner-freebsd-threads@FreeBSD.ORG>
Delivered-To: freebsd-threads@freebsd.org
Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125])
	by hub.freebsd.org (Postfix) with ESMTP id 4B5F316A4D0
	for <freebsd-threads@freebsd.org>;
	Thu, 19 Feb 2004 05:48:15 -0800 (PST)
Received: from smtp02.syd.iprimus.net.au (smtp02.syd.iprimus.net.au
	[210.50.76.52])	by mx1.FreeBSD.org (Postfix) with ESMTP id 20FFD43D1D
	for <freebsd-threads@freebsd.org>;
	Thu, 19 Feb 2004 05:48:15 -0800 (PST)
	(envelope-from tim@robbins.dropbear.id.au)
Received: from robbins.dropbear.id.au (210.50.217.1) by
	smtp02.syd.iprimus.net.au (7.0.024)
	id 402CF87000199257; Fri, 20 Feb 2004 00:48:13 +1100
Received: by robbins.dropbear.id.au (Postfix, from userid 1000)
	id 6D96341C0; Fri, 20 Feb 2004 00:47:33 +1100 (EST)
Date: Fri, 20 Feb 2004 00:47:33 +1100
From: Tim Robbins <tjr@freebsd.org>
To: Mike Makonnen <mtm@identd.net>
Message-ID: <20040219134733.GA38023@cat.robbins.dropbear.id.au>
References: <20040219062850.GC1074@mobile.acs-et.com>
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20040219062850.GC1074@mobile.acs-et.com>
User-Agent: Mutt/1.4.1i
cc: freebsd-threads@freebsd.org
Subject: Re: libthr patch
X-BeenThere: freebsd-threads@freebsd.org
X-Mailman-Version: 2.1.1
Precedence: list
List-Id: Threading on FreeBSD <freebsd-threads.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-threads>,
	<mailto:freebsd-threads-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-threads>
List-Post: <mailto:freebsd-threads@freebsd.org>
List-Help: <mailto:freebsd-threads-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-threads>,
	<mailto:freebsd-threads-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Thu, 19 Feb 2004 13:48:15 -0000

On Thu, Feb 19, 2004 at 09:28:50AM +0300, Mike Makonnen wrote:

> Index: sys/kern/kern_thr.c
[...]
> +int
> +thr_wake(struct thread *td, struct thr_wake_args *uap)
> +	/* thr_id_t id */
> +{
> +	PROC_LOCK(((struct thread *)uap->id)->td_proc);
> +	((struct thread *)uap->id)->td_lthrflags |= LTF_THRWAKEUP;
> +	PROC_UNLOCK(((struct thread *)uap->id)->td_proc);
> +	wakeup_one((void *)uap->id);
> +	return (0);
> +}
[...]

Make sure you fix thr_wake() to check that uap->id is valid before you
commit this patch. Something like this would be safer but slower:

	struct thread *td1;

	PROC_LOCK(td->td_proc);
	FOREACH_THREAD_IN_PROC(td->td_proc, td1)
		if (td1 == (struct thread *)uap->id)
			break;
	if (td1 == NULL) {
		PROC_UNLOCK(td->td_proc);
		return (ESRCH);
	}
	td1->td_lthrflags |= LTF_THRWAKEUP;
	wakeup_one(td1);
	PROC_UNLOCK(td->td_proc);
	return (0);

(I'm not sure that it's safe to call wakeup_one() on a thread pointer
that isn't curthread without holding the proc lock, so I changed that too.)


Tim