Messages in this thread | | | Date | Fri, 5 Aug 2022 15:25:52 +0200 | From | Borislav Petkov <> | Subject | Re: [PATCH v2] x86,mm: print likely CPU at segfault time |
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On Fri, Aug 05, 2022 at 08:53:46AM -0400, Rik van Riel wrote: > Having a small percentage of the segfaults show up on > cores other than the broken one does not cause issues with > detection or diagnosis.
I'm sorry but I'm not buying any of this: this should either be 100% correct or it can stay on your kernels.
> We could, but then we would be reading the CPU number > on every page fault, just in case it's a segfault. > > That does not seem like a worthwhile tradeoff, given > how much of a hot path page faults are, and how rare > segfaults are.
Oh wow, a whopping single instruction:
movl %gs:cpu_number(%rip), %eax # cpu_number, pfo_val__
What tradeoff?
-- Regards/Gruss, Boris.
https://people.kernel.org/tglx/notes-about-netiquette
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