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From: Andrea Arcangeli <andrea@suse.de>
To: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: David Mosberger <davidm@hpl.hp.com>, linux-kernel@vger.kernel.org
Subject: Re: [patch] proposed fix for ptrace() SMP race
Date: Fri, 7 Sep 2001 15:34:25 +0200	[thread overview]
Message-ID: <20010907153425.P11329@athlon.random> (raw)
In-Reply-To: <20010907032801.N11329@athlon.random> <E15fAdr-0000r7-00@the-village.bc.nu>
In-Reply-To: <E15fAdr-0000r7-00@the-village.bc.nu>; from alan@lxorguk.ukuu.org.uk on Fri, Sep 07, 2001 at 02:41:11AM +0100

On Fri, Sep 07, 2001 at 02:41:11AM +0100, Alan Cox wrote:
> > +#ifdef CONFIG_SMP
> > +	rmb(); /* read child->has_cpu after child->state */
> > +	while (child->has_cpu);
> 		rep_nop();
> 
> otherwise your PIV will overheat

indeed correct (OTOH it's a so small window [not like a contended
spinlock] that I wonder if it will make a difference in real life ;)

Andrea

  reply	other threads:[~2001-09-07 13:34 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2001-09-06 23:00 [patch] proposed fix for ptrace() SMP race David Mosberger
2001-09-07  0:19 ` Andrea Arcangeli
2001-09-07  0:40   ` David Mosberger
2001-09-07  1:28     ` Andrea Arcangeli
2001-09-07  1:41       ` Alan Cox
2001-09-07 13:34         ` Andrea Arcangeli [this message]
2001-09-07  5:21       ` David Mosberger
2001-09-07 13:28         ` Andrea Arcangeli
2001-09-07 15:35           ` David Mosberger
2001-09-08 17:11             ` Andrea Arcangeli
2001-09-10 17:20               ` David Mosberger
  -- strict thread matches above, loose matches on Subject: below --
2001-09-10 17:54 Manfred Spraul

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