Messages in this thread | | | Date | Fri, 27 Aug 2010 14:29:28 -0500 (CDT) | From | Christoph Lameter <> | Subject | Re: [PATCH] mm: fix hang on anon_vma->root->lock |
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On Fri, 27 Aug 2010, Hugh Dickins wrote:
> Eh? My solution was a second page_mapped(page) test i.e. testing an atomic.
Argh. Right. Looked like a global to me. Did not see the earlier local def.
If you still use a pointer then what does insure that the root pointer was not changed after the ACCESS_ONCE? The free semantics of an anon_vma?
Since there is no lock taken before the mapped check none of the earlier reads from the anon vma structure nor the page mapped check necessarily reflect a single state of the anon_vma.
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