User space may create the PIT and forgets about setting up the irqchips. In that case, firing PIT IRQs will crash the host: BUG: unable to handle kernel NULL pointer dereference at 0000000000000128 IP: [<ffffffffa10f6280>] kvm_set_irq+0x30/0x170 [kvm] ... Call Trace: [<ffffffffa11228c1>] pit_do_work+0x51/0xd0 [kvm] [<ffffffff81071431>] process_one_work+0x111/0x4d0 [<ffffffff81071bb2>] worker_thread+0x152/0x340 [<ffffffff81075c8e>] kthread+0x7e/0x90 [<ffffffff815a4474>] kernel_thread_helper+0x4/0x10 Reference: http://permalink.gmane.org/gmane.comp.emulators.kvm.devel/83564
CVE-2011-4622 (http://nvd.nist.gov/nvd.cfm?cvename=CVE-2011-4622): The create_pit_timer function in arch/x86/kvm/i8254.c in KVM 83, and possibly other versions, does not properly handle when Programmable Interval Timer (PIT) interrupt requests (IRQs) when a virtual interrupt controller (irqchip) is not available, which allows local users to cause a denial of service (NULL pointer dereference) by starting a timer.
This only affects the Kernel side, no GLSA will be released.
kvm was merged in kernel in version 2.6.20. There are no longer any 2.x kernels available in the repository with the exception of sys-kernel/xbox-sources which is unsupported by security.