Messages in this thread | | | Date | Tue, 21 Aug 2007 23:28:28 -0700 | From | Jeremy Fitzhardinge <> | Subject | Re: [PATCH] Fix lazy mode vmalloc synchronization for paravirt |
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Zachary Amsden wrote: > Found this looping Ubuntu installs with VMI. > > If unlucky enough to hit a vmalloc sync fault during a lazy mode > operation (from an IRQ handler for a module which was not yet > populated in current page directory, or from inside copy_one_pte, > which touches swap_map, and hit in an unused 4M region), the required > PDE update would never get flushed, causing an infinite page fault loop.
Ah, good catch.
> This bug affects any paravirt-ops backend which uses lazy updates, I > believe that makes it a bug in Xen, VMI and lguest. It only happens > on LOWMEM kernels.
No, under Xen the kernel/hypervisor PMD is not shared between processes, so this is still used when PAE is enabled.
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