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authorAvi Kivity <avi@redhat.com>2009-01-05 15:21:42 +0200
committerAvi Kivity <avi@redhat.com>2009-03-24 11:03:01 +0200
commit269e05e48502f1cc06802e9fba90f5100dd6bb0d (patch)
tree9b3501dc1f5e137c2dca7eacf15c0353f627be97 /arch/x86/kvm
parentKVM: x86 emulator: implement 'ret far' instruction (opcode 0xcb) (diff)
downloadlinux-dev-269e05e48502f1cc06802e9fba90f5100dd6bb0d.tar.xz
linux-dev-269e05e48502f1cc06802e9fba90f5100dd6bb0d.zip
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>
Diffstat (limited to 'arch/x86/kvm')
-rw-r--r--arch/x86/kvm/i8254.c2
-rw-r--r--arch/x86/kvm/x86.c6
2 files changed, 6 insertions, 2 deletions
diff --git a/arch/x86/kvm/i8254.c b/arch/x86/kvm/i8254.c
index 528daadeba49..69d1bbff3fd3 100644
--- a/arch/x86/kvm/i8254.c
+++ b/arch/x86/kvm/i8254.c
@@ -548,9 +548,7 @@ struct kvm_pit *kvm_create_pit(struct kvm *kvm)
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 a1f14611f4b9..6fbc34603375 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1837,10 +1837,16 @@ long kvm_arch_vm_ioctl(struct file *filp,
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;