[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] Re: One (possible) x86 get_user_pages bug
On Thu, 2011-01-27 at 16:07 +0000, Jan Beulich wrote: > > Nick, based on your doing of the initial implementation, would > you be able to estimate whether disabling get_user_pages_fast() > altogether for Xen would be performing measurably worse than > adding the locks (but continuing to avoid acquiring mm->mmap_sem) > as suggested by Xiaowei? That's of course only if the latter is correct > at all, of which I haven't fully convinced myself yet. Also, I don't think taking the pte_lock is sufficient in your case.. since x86 mmu_gather frees the page tables themselves too, your dereference of the pgd/pud/pmd will be subject to the same deref after free problems. _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-devel
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