VFIO: unregister IOMMU notifier on error recovery path

On error recovery path in function vfio_create_group(), it should
unregister the IOMMU notifier for the new VFIO group. Otherwise it may
cause invalid memory access later when handling bus notifications.

Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c
index 56097c6d072d0797ecc9c13c9d2d231aa3e9afa8..3b7fa7967221dfa85c72fddb61123641df8c5fae 100644 (file)
--- a/drivers/vfio/vfio.c
+++ b/drivers/vfio/vfio.c
@@ -191,6 +191,17 @@ static void vfio_container_put(struct vfio_container *container)
        kref_put(&container->kref, vfio_container_release);
 }
 
+static void vfio_group_unlock_and_free(struct vfio_group *group)
+{
+       mutex_unlock(&vfio.group_lock);
+       /*
+        * Unregister outside of lock.  A spurious callback is harmless now
+        * that the group is no longer in vfio.group_list.
+        */
+       iommu_group_unregister_notifier(group->iommu_group, &group->nb);
+       kfree(group);
+}
+
 /**
  * Group objects - create, release, get, put, search
  */
@@ -229,8 +240,7 @@ static struct vfio_group *vfio_create_group(struct iommu_group *iommu_group)
 
        minor = vfio_alloc_group_minor(group);
        if (minor < 0) {
-               mutex_unlock(&vfio.group_lock);
-               kfree(group);
+               vfio_group_unlock_and_free(group);
                return ERR_PTR(minor);
        }
 
@@ -239,8 +249,7 @@ static struct vfio_group *vfio_create_group(struct iommu_group *iommu_group)
                if (tmp->iommu_group == iommu_group) {
                        vfio_group_get(tmp);
                        vfio_free_group_minor(minor);
-                       mutex_unlock(&vfio.group_lock);
-                       kfree(group);
+                       vfio_group_unlock_and_free(group);
                        return tmp;
                }
        }
@@ -249,8 +258,7 @@ static struct vfio_group *vfio_create_group(struct iommu_group *iommu_group)
                            group, "%d", iommu_group_id(iommu_group));
        if (IS_ERR(dev)) {
                vfio_free_group_minor(minor);
-               mutex_unlock(&vfio.group_lock);
-               kfree(group);
+               vfio_group_unlock_and_free(group);
                return (struct vfio_group *)dev; /* ERR_PTR */
        }
 
@@ -274,16 +282,7 @@ static void vfio_group_release(struct kref *kref)
        device_destroy(vfio.class, MKDEV(MAJOR(vfio.devt), group->minor));
        list_del(&group->vfio_next);
        vfio_free_group_minor(group->minor);
-
-       mutex_unlock(&vfio.group_lock);
-
-       /*
-        * Unregister outside of lock.  A spurious callback is harmless now
-        * that the group is no longer in vfio.group_list.
-        */
-       iommu_group_unregister_notifier(group->iommu_group, &group->nb);
-
-       kfree(group);
+       vfio_group_unlock_and_free(group);
 }
 
 static void vfio_group_put(struct vfio_group *group)