Re: [patch 1/2] x86_64 page fault NMI-safe

[H. Peter Anvin]

On 07/15/2010 04:44 PM, Linus Torvalds wrote:
> On Thu, Jul 15, 2010 at 4:41 PM, H. Peter Anvin <hpa@xxxxxxxxx> wrote:
>>
>> No, the problem is that without IST it'll try to drop the NMI stack
>> frame itself *on the user stack*.
> 
> Oh, because SS has already been cleared, but rsp still points to the
> user stack? Ok, that does seem insurmountable.
> 

Well, SS doesn't matter for 64 bits, but yes, RSP still points to the
user stack.

	-hpa

-- 
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel.  I don't speak on their behalf.

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