diff mbox series

[5.11,253/329] KVM: x86: Cancel pvclock_gtod_work on module removal

Message ID 20210517140310.665706942@linuxfoundation.org
State New
Headers show
Series None | expand

Commit Message

Greg Kroah-Hartman May 17, 2021, 2:02 p.m. UTC 
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 mbox series

Patch

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 3b3f96e87b8c..b010ad6cbd14 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -8005,6 +8005,7 @@  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();