KVM: x86: Cancel pvclock_gtod_work on module removal

[ 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: 16e8d74d2d ("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>
This commit is contained in:
Thomas Gleixner 2021-05-05 23:48:17 +02:00 committed by Greg Kroah-Hartman
parent 1fe2693722
commit 8aa7227a5d

View File

@ -7981,6 +7981,7 @@ void kvm_arch_exit(void)
cpuhp_remove_state_nocalls(CPUHP_AP_X86_KVM_CLK_ONLINE); cpuhp_remove_state_nocalls(CPUHP_AP_X86_KVM_CLK_ONLINE);
#ifdef CONFIG_X86_64 #ifdef CONFIG_X86_64
pvclock_gtod_unregister_notifier(&pvclock_gtod_notifier); pvclock_gtod_unregister_notifier(&pvclock_gtod_notifier);
cancel_work_sync(&pvclock_gtod_work);
#endif #endif
kvm_x86_ops.hardware_enable = NULL; kvm_x86_ops.hardware_enable = NULL;
kvm_mmu_module_exit(); kvm_mmu_module_exit();