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

Herbert Xu
2008-08-09T14:37:53Z

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.

Cheers,
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