Re: [PATCH] ppc64: Fix possible race with set_pte on a present PTE

From: Linus Torvalds
Date: Tue May 25 2004 - 11:21:21 EST




On Tue, 25 May 2004, Keith M Wesolowski wrote:
>
> Some sparc32 CPUs are also vulnerable to this race; in fact the
> supersparc manual describes it specifically and even outlines the
> compare-exchange loop using our rotten swap instruction. In our case,
> the race is with a hardware walker.

Yes, but the sparc32 page tables are not the same as the linux kernel page
tables, so in your case it's a different path and a different page table.
Only the shared case really matters (ie things that do hw/microcode walk
of a page table _tree_ not a hash).

Linus
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