diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index d9bbb20..29a667c 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -466,6 +466,7 @@
 	struct kvm_assigned_dev_kernel *match;
 	struct pci_dev *dev;
 
+	down_read(&kvm->slots_lock);
 	mutex_lock(&kvm->lock);
 
 	match = kvm_find_assigned_dev(&kvm->arch.assigned_dev_head,
@@ -527,6 +528,7 @@
 
 out:
 	mutex_unlock(&kvm->lock);
+	up_read(&kvm->slots_lock);
 	return r;
 out_list_del:
 	list_del(&match->list);
@@ -538,6 +540,7 @@
 out_free:
 	kfree(match);
 	mutex_unlock(&kvm->lock);
+	up_read(&kvm->slots_lock);
 	return r;
 }
 #endif