Messages in this thread | | | Date | Mon, 12 Apr 2010 11:51:41 -0400 | From | Rik van Riel <> | Subject | Re: [PATCH -v2] rmap: make anon_vma_prepare link in all the anon_vmas of a mergeable VMA |
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On 04/12/2010 11:44 AM, Linus Torvalds wrote: > On Sun, 11 Apr 2010, Rik van Riel wrote: >> >> Looking around the code some more, zap_pte_range() >> calls page_remove_rmap(), which leaves the >> page->mapping in place and has this comment: > > See my earlier email about this exact issue. It's well-known that there > are stale page->mapping pointers. The "page_mapped()" check _should_ have > meant that in that case we never follow them, though.
Good point. I wonder if we have some SMP reordering issue then?
>> I wonder if we can clear page->mapping here, if >> list_is_singular(anon_vma->head). That way we >> will not leave stale pointers behind. > > What does that help? What if list _isn't_ singular?
Yeah, that was a bad idea. Looking at the same code for 11 days straight seems to have put some knots in my brain :)
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