From: Thomas Gleixner tglx@linutronix.de
[ Upstream commit 594b27e677b35f9734b1969d175ebc6146741109 ]
Nothing prevents the following:
pvclock_gtod_notify() queue_work(system_long_wq, &pvclock_gtod_work); ... remove_module(kvm); ... work_queue_run() pvclock_gtod_work() <- UAF
Ditto for any other operation on that workqueue list head which touches pvclock_gtod_work after module removal.
Cancel the work in kvm_arch_exit() to prevent that.
Fixes: 16e8d74d2da9 ("KVM: x86: notifier for clocksource changes") Signed-off-by: Thomas Gleixner tglx@linutronix.de Message-Id: 87czu4onry.ffs@nanos.tec.linutronix.de Cc: stable@vger.kernel.org Signed-off-by: Paolo Bonzini pbonzini@redhat.com Signed-off-by: Sasha Levin sashal@kernel.org --- arch/x86/kvm/x86.c | 1 + 1 file changed, 1 insertion(+)
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 3406ff421c1a..f1fd52eddabf 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -8096,6 +8096,7 @@ void kvm_arch_exit(void) cpuhp_remove_state_nocalls(CPUHP_AP_X86_KVM_CLK_ONLINE); #ifdef CONFIG_X86_64 pvclock_gtod_unregister_notifier(&pvclock_gtod_notifier); + cancel_work_sync(&pvclock_gtod_work); #endif kvm_x86_ops.hardware_enable = NULL; kvm_mmu_module_exit();