From ba4cef31d5a397b64ba6d3ff713ce06c62f0c597 Mon Sep 17 00:00:00 2001 From: Sheng Yang Date: Tue, 6 Jan 2009 10:03:03 +0800 Subject: KVM: Fix racy in kvm_free_assigned_irq In the past, kvm_get_kvm() and kvm_put_kvm() was called in assigned device irq handler and interrupt_work, in order to prevent cancel_work_sync() in kvm_free_assigned_irq got a illegal state when waiting for interrupt_work done. But it's tricky and still got two problems: 1. A bug ignored two conditions that cancel_work_sync() would return true result in a additional kvm_put_kvm(). 2. If interrupt type is MSI, we would got a window between cancel_work_sync() and free_irq(), which interrupt would be injected again... This patch discard the reference count used for irq handler and interrupt_work, and ensure the legal state by moving the free function at the very beginning of kvm_destroy_vm(). And the patch fix the second bug by disable irq before cancel_work_sync(), which may result in nested disable of irq but OK for we are going to free it. Signed-off-by: Sheng Yang Signed-off-by: Avi Kivity --- arch/x86/kvm/x86.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'arch') diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index b0fc079f1be..fc3e329f6ad 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -4129,11 +4129,11 @@ static void kvm_free_vcpus(struct kvm *kvm) void kvm_arch_sync_events(struct kvm *kvm) { + kvm_free_all_assigned_devices(kvm); } void kvm_arch_destroy_vm(struct kvm *kvm) { - kvm_free_all_assigned_devices(kvm); kvm_iommu_unmap_guest(kvm); kvm_free_pit(kvm); kfree(kvm->arch.vpic); -- cgit v1.2.3