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

[Linus Torvalds]

On Thu, Jul 15, 2010 at 4:20 PM, H. Peter Anvin <hpa@xxxxxxxxx> wrote:
> On 07/15/2010 03:58 PM, Andi Kleen wrote:
>>> Why do we force IST use for NMI, btw? Maybe we shouldn't, and just use
>>> the normal kernel stack mechanisms?
>>
>> If you don't use IST the SYSCALL entry is racy during the window
>> when RSP is not set up yet (same for MCE etc.)
>>
>
> Right, the kernel stack is not ready.

Well, it may not be ready for the _current_ NMI handler, but if we're
going to do a stack switch in sw on NMI anyway... ?

                 Linus
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/