Prev: input: Fix wrong dimensions check for synaptics
Next: x86: NMI-safe trap handlers
From: H. Peter Anvin on 4 Aug 2010 16:30
On 08/04/2010 02:46 AM, Peter Zijlstra wrote:
> On Fri, 2010-07-16 at 11:05 -0700, H. Peter Anvin wrote:
>>
>> I really hope noone ever gets the idea of touching user space from an
>> NMI handler, though, and expecting it to work...
>
> Perf actually already does that to unwind user-space stacks... ;-)
>
> See arch/x86/kernel/cpu/perf_event.c:copy_from_user_nmi() and its users.
>
> What we do is a manual page table walk (using __get_user_pages_fast) and
> simply bail when the page is not available.
>

That's not really "touching user space", though.

-hpa
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo(a)vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
First  |  Prev  | 
Pages: 1 2 3 4 5 6 7 8
Prev: input: Fix wrong dimensions check for synaptics
Next: x86: NMI-safe trap handlers