KVM: Properly lock PIT creation
Otherwise, two threads can create a PIT in parallel and cause a memory leak.
Signed-off-by: Avi Kivity <avi@redhat.com>
diff --git a/arch/x86/kvm/i8254.c b/arch/x86/kvm/i8254.c
index 528daad..69d1bbff 100644
--- a/arch/x86/kvm/i8254.c
+++ b/arch/x86/kvm/i8254.c
@@ -548,9 +548,7 @@
if (!pit)
return NULL;
- mutex_lock(&kvm->lock);
pit->irq_source_id = kvm_request_irq_source_id(kvm);
- mutex_unlock(&kvm->lock);
if (pit->irq_source_id < 0) {
kfree(pit);
return NULL;
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index a1f1461..6fbc346 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1837,10 +1837,16 @@
goto out;
break;
case KVM_CREATE_PIT:
+ mutex_lock(&kvm->lock);
+ r = -EEXIST;
+ if (kvm->arch.vpit)
+ goto create_pit_unlock;
r = -ENOMEM;
kvm->arch.vpit = kvm_create_pit(kvm);
if (kvm->arch.vpit)
r = 0;
+ create_pit_unlock:
+ mutex_unlock(&kvm->lock);
break;
case KVM_IRQ_LINE: {
struct kvm_irq_level irq_event;