KVM: fix lock imbalance in kvm_*_irq_source_id()

commit 0c6ddcebd8303ada6faefa6f72ac18b6230320c4 upstream.

Stanse found 2 lock imbalances in kvm_request_irq_source_id and
kvm_free_irq_source_id. They omit to unlock kvm->irq_lock on fail paths.

Fix that by adding unlock labels at the end of the functions and jump
there from the fail paths.

Signed-off-by: Jiri Slaby <jirislaby@gmail.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/virt/kvm/irq_comm.c b/virt/kvm/irq_comm.c
index 03e5b217e88b9f640e9c3c3c4b1b50a96303b6f4..ddc388e565fc459aec5f5e1168bf8f6c7b7535b5 100644 (file)
--- a/virt/kvm/irq_comm.c
+++ b/virt/kvm/irq_comm.c
@@ -209,11 +209,13 @@ int kvm_request_irq_source_id(struct kvm *kvm)
 
        if (irq_source_id >= BITS_PER_LONG) {
                printk(KERN_WARNING "kvm: exhaust allocatable IRQ sources!\n");
-               return -EFAULT;
+               irq_source_id = -EFAULT;
+               goto unlock;
        }
 
        ASSERT(irq_source_id != KVM_USERSPACE_IRQ_SOURCE_ID);
        set_bit(irq_source_id, bitmap);
+unlock:
        mutex_unlock(&kvm->irq_lock);
 
        return irq_source_id;
@@ -229,11 +231,12 @@ void kvm_free_irq_source_id(struct kvm *kvm, int irq_source_id)
        if (irq_source_id < 0 ||
            irq_source_id >= BITS_PER_LONG) {
                printk(KERN_ERR "kvm: IRQ source ID out of range!\n");
-               return;
+               goto unlock;
        }
        for (i = 0; i < KVM_IOAPIC_NUM_PINS; i++)
                clear_bit(irq_source_id, &kvm->arch.irq_states[i]);
        clear_bit(irq_source_id, &kvm->arch.irq_sources_bitmap);
+unlock:
        mutex_unlock(&kvm->irq_lock);
 }