CVE request -- kernel: kvm: irqchip_in_kernel() and vcpu->arch.apic inconsistency

[Petr Matousek <pmatouse () redhat com>]

If some vcpus are created before KVM_CREATE_IRQCHIP, then
irqchip_in_kernel() and vcpu->arch.apic will be inconsistent, leading to
potential NULL pointer dereferences.

A unprivileged local user could use this flaw to crash the system.

Upstream fix:
http://git.kernel.org/?p=virt/kvm/kvm.git;a=commit;h=5b40572ed5f0344b9dbee486a17c589ce1abe1a3

References:
http://comments.gmane.org/gmane.comp.emulators.kvm.devel/86217
https://bugzilla.redhat.com/show_bug.cgi?id=808199

Thanks,
-- 
Petr Matousek / Red Hat Security Response Team