virt/kvm/assigned-dev.c: Set 'dev->irq_source_id' to '-1' after free it

As a generic function, deassign_guest_irq() assumes it can be called
even if assign_guest_irq() is not be called successfully (which can be
triggered by ioctl from user mode, indirectly).

So for assign_guest_irq() failure process, need set 'dev->irq_source_id'
to -1 after free 'dev->irq_source_id', or deassign_guest_irq() may free
it again.

Signed-off-by: Chen Gang <gang.chen.5i5j@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 3 insertions, 1 deletions

diff --git a/virt/kvm/assigned-dev.c b/virt/kvm/assigned-dev.c
index bf06577fea51..5819a2708d7e 100644
--- a/virt/kvm/assigned-dev.c
+++ b/virt/kvm/assigned-dev.c
@@ -526,8 +526,10 @@ static int assign_guest_irq(struct kvm *kvm,
                 dev->irq_requested_type |= guest_irq_type;
                 if (dev->ack_notifier.gsi != -1)
                         kvm_register_irq_ack_notifier(kvm, &dev->ack_notifier);
-        } else
+        } else {
                 kvm_free_irq_source_id(kvm, dev->irq_source_id);
+                dev->irq_source_id = -1;
+        }
 
         return r;
 }