Messages in this thread | | | Date | Sat, 9 Aug 2008 11:14:06 -0700 | From | Suresh Siddha <> | Subject | Re: Kernel oops with 2.6.26, padlock and ipsec: probably problem with fpu state changes |
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On Sat, Aug 09, 2008 at 09:05:50AM -0700, H. Peter Anvin wrote: > 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?
Yes. Padlock/ipsec usage seems to be happening in the interrupt context and this triggered the bug that started this thread.
thanks, suresh
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