Messages in this thread Patch in this message |  | | | Date | Tue, 09 Jan 2007 23:26:48 +0200 | | From | Avi Kivity <> | | Subject | Re: [kvm-devel] guest crash on 2.6.20-rc4 |
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Roland Dreier wrote: > I'm running a 64-bit Fedora 6 install as a guest on a host running > 2.6.20-rc4 with the kvm-10 userspace release. The CPU is a Xeon 5160 > and I have 6 GB of RAM. The guest is given 512 MB of memory. I left > the guest idle overnight, and the makewhatis cron job seems to have > triggered this: > > Unable to handle kernel paging request at ffff81000ba04000 RIP: > [<ffffffff8025f402>] clear_page+0x16/0x44 >
I've managed to reproduce a bug with similar characteristics: a write fault into a present, writable kernel page. The attached patch should fix it.
-- Do not meddle in the internals of kernels, for they are subtle and quick to panic.
Index: b/drivers/kvm/paging_tmpl.h =================================================================== --- a/drivers/kvm/paging_tmpl.h (revision 4270) +++ b/drivers/kvm/paging_tmpl.h (working copy) @@ -274,7 +274,7 @@ struct kvm_mmu_page *page; if (is_writeble_pte(*shadow_ent)) - return 0; + return 1; writable_shadow = *shadow_ent & PT_SHADOW_WRITABLE_MASK; if (user) { |  |