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) {
