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From: Andi Kleen <andi@firstfloor.org>
To: Ingo Molnar <public-mingo-X9Un+BFzKDI@hugh.gmane.org>
Cc: Neil Horman 
	<public-nhorman-2XuSBdqkA4R54TAoqtyWWQ@hugh.gmane.org>,
	public-kexec-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@hugh.gmane.org,
	public-linux-kernel-u79uwXL29TY76Z2rM5mHXA@hugh.gmane.org,
	public-mingo-H+wXaHxf7aLQT0dZR+AlfA@hugh.gmane.org,
	"Eric W. Biederman" 
	<public-ebiederm-aS9lmoZGLiVWk0Htik3J/w@hugh.gmane.org>,
	"H. Peter Anvin"
	<public-hpa-YMNOUZJC4hwAvxtiuMwx3w@hugh.gmane.org>,
	public-tglx-hfZtesqFncYOwBW4kG4KsQ@hugh.gmane.org,
	Vivek Goyal <public-vgoyal-H+wXaHxf7aLQT0dZR+AlfA@hugh.gmane.org>
Subject: Re: [PATCH], issue EOI to APIC prior to calling crash_kexec in die_nmi path
Date: Fri, 08 Feb 2008 17:54:29 +0100	[thread overview]
Message-ID: <p73ir0z2xtm.fsf@bingen.suse.de> (raw)
In-Reply-To: <20080207122404.GA8195@elte.hu> (Ingo Molnar's message of "Thu\, 7 Feb 2008 13\:24\:04 +0100")



Ingo Molnar <mingo-X9Un+BFzKDI@public.gmane.org> writes:
>
> try a dummy iret, something like:
>
>   asm volatile ("pushf; push $1f; iret; 1: \n");
>
> to get the CPU out of its 'nested NMI' state. (totally untested)

Just if you do this while running on the NMI stack (and I think
you do if you insert it at the same place as Neil's original patch)
and another NMI happens for some reason you will be dead
because your stack will corrupt.

If you really want nested NMIs you would need to fix up the NMI
stacks first by pointing them below your own stack.

-Andi


      parent reply	other threads:[~2008-02-08 17:23 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-02-06 19:25 Neil Horman
2008-02-06 19:40 ` Vivek Goyal
2008-02-06 20:12   ` Neil Horman
2008-02-06 20:21     ` H. Peter Anvin
2008-02-06 21:04       ` Neil Horman
2008-02-06 20:35     ` Vivek Goyal
2008-02-06 22:00 ` Ingo Molnar
2008-02-06 22:48   ` Vivek Goyal
2008-02-06 22:53     ` Ingo Molnar
2008-02-06 22:56     ` H. Peter Anvin
2008-02-06 23:36       ` Ingo Molnar
2008-02-06 23:50         ` Vivek Goyal
2008-02-07  0:31         ` Eric W. Biederman
2008-02-07  0:39           ` Ingo Molnar
2008-02-07  1:30             ` Eric W. Biederman
2008-02-07 12:17           ` Neil Horman
2008-02-07 12:24             ` Ingo Molnar
2008-02-07 20:37               ` Neil Horman
2008-02-08 16:14               ` Neil Horman
2008-02-08 16:45                 ` Vivek Goyal
2008-02-08 17:26                   ` Neil Horman
2008-02-12 21:08                   ` Neil Horman
2008-02-15 14:02                     ` Eric W. Biederman
2008-02-20 14:57                     ` Neil Horman
2008-02-08 16:54               ` Andi Kleen [this message]

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