Re: Kernel oops with 2.6.26, padlock and ipsec: probably problem with fpu state changes

H. Peter Anvin
2008-08-09T16:12:45Z

Herbert Xu wrote:
> On Fri, Aug 08, 2008 at 04:11:21PM -0700, Suresh Siddha wrote:
>> With out the recent dynamic fpu allocation changes, while we don't see oops,
>> there is a possible race still present in older kernels(for example,
>> while kernel is using kernel_fpu_begin() in some optimized clear/copy
>> page and an interrupt/softirq happens which uses these padlock
>> instructions generating DNA fault).
>
> No this wasn't a problem because kernel_fpu_begin clears TS and
> therefore we don't get faults on SSE instructions.
>
> However, with your patch it will become a problem due to the
> fact that it wasn't designed to be nested.
>

We're invoking this code from interrupt handlers?

-hpa