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From: "H. Peter Anvin" <hpa@zytor.com>
To: Sasha Levin <sasha.levin@oracle.com>
Cc: tglx@linutronix.de, mingo@redhat.com, x86@kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH] x86-64, espfix: consider IRQs are off when initializing
Date: Thu, 17 Jul 2014 08:48:51 -0700	[thread overview]
Message-ID: <53C7F063.7030007@zytor.com> (raw)
In-Reply-To: <1405610015-27464-1-git-send-email-sasha.levin@oracle.com>

On 07/17/2014 08:13 AM, Sasha Levin wrote:
> When going through our initialization code (init_espfix_ap() ) we need to
> keep in mind IRQs are off, and we need to handle it appropriately:
> 
>  - Do not allocate with __GFP_FS.
>  - No point in using a mutex.
> 
> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>

I don't think this is safe.  The whole point was that if we do
GFP_ATOMIC we have to accept failure, and if we have a spin lock then
sleeping is not permitted.  It is unclear to me is sleeping is safe in
this context even so, so we may still have a problem, but calling
__get_free_page(GFP_ATOMIC) and then unconditionally use the results is
not right.

	-hpa


  reply	other threads:[~2014-07-17 15:49 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-07-17 15:13 [PATCH] x86-64, espfix: consider IRQs are off when initializing Sasha Levin
2014-07-17 15:48 ` H. Peter Anvin [this message]
2014-07-17 15:58   ` Sasha Levin
2014-07-17 16:16     ` H. Peter Anvin

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