Re: race with page_referenced_one->ptep_test_and_clear_young and pagetable setup/pulldown

Nick Piggin
2007-10-08T02:24:39Z

On Friday 05 October 2007 12:44, Andrew Morton wrote:
> On Thu, 04 Oct 2007 18:43:32 -0700 Jeremy Fitzhardinge <jeremy@goop.org>
wrote:
> > David's change 10a8d6ae4b3182d6588a5809a8366343bc295c20, "i386: add
> > ptep_test_and_clear_{dirty,young}" has introduced an SMP race which
> > affects the Xen pv-ops backend.
>
> y'know, I think I think it's been several years since I saw a report of an
> honest to goodness, genuine SMP race in core kernel. We used to be
> infested by them, but the term has fallen into disuse. Interesting, but
> OT.

Does that include data races on weakly ordered systems, or UP races
(ie. with sleeping locks rather than spinning ones)? ;) Because we had
and have a few of those...