From 8aa7227a5d9b4ff8ea42bf653fbf8c08d7744e9d Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Wed, 5 May 2021 23:48:17 +0200 Subject: [PATCH] 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: 16e8d74d2da9 ("KVM: x86: notifier for clocksource changes") Signed-off-by: Thomas Gleixner Message-Id: <87czu4onry.ffs@nanos.tec.linutronix.de> Cc: stable@vger.kernel.org Signed-off-by: Paolo Bonzini Signed-off-by: Sasha Levin --- 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 25660cac6ad42..4bd99f046b0cc 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -7981,6 +7981,7 @@ 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();