[Qemu-devel] [PATCH v3] qdev: Avoid type assertion in qdev_build_hotpluggable_device_list()

[Jun Li <junmuzi@gmail.com>]

Currently when *obj is not a TYPE_DEVICE, qemu will abort. This patch just
fixed it. When *obj is not a TYPE_DEVICE, just do not add it to hotpluggable
device list.

This patch also fixed the following issue:
1, boot qemu using cli:
$ /opt/qemu-git-arm/bin/qemu-system-x86_64 -monitor stdio -enable-kvm \
-device virtio-scsi-pci,id=scsi0

2, device_del scsi0 via hmp using tab key(first input device_del, then press
"Tab" key).
(qemu) device_del

After step2, qemu will abort.
(qemu) device_del hw/core/qdev.c:930:qdev_build_hotpluggable_device_list:
Object 0x5555563a2460 is not an instance of type device

Signed-off-by: Jun Li <junmuzi@gmail.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
---
v3:
  According to Andreas's suggestion, do some changes. As followings:
  1, change the Subject to more meaningful.
  2, use two "return 0" to return early avoid reindentation. And I have found in qcow2_grow_l1_table has also used two "return 0". So accept Andreas's suggestion. Thanks.

v2:
  This version just do a little changes for the commit message.
As following show:
In v1,
1, boot qemu using cli:
virtio-scsi-pci,id=scsi0 -enable-kvm

In v2,
1, boot qemu using cli:
$ /opt/qemu-git-arm/bin/qemu-system-x86_64 -monitor stdio -enable-kvm \
-device virtio-scsi-pci,id=scsi0
---
 hw/core/qdev.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/hw/core/qdev.c b/hw/core/qdev.c
index b3d5196..7db3e13 100644
--- a/hw/core/qdev.c
+++ b/hw/core/qdev.c
@@ -927,7 +927,12 @@ void qdev_alias_all_properties(DeviceState *target, Object *source)
 int qdev_build_hotpluggable_device_list(Object *obj, void *opaque)
 {
     GSList **list = opaque;
-    DeviceState *dev = DEVICE(obj);
+    DeviceState *dev = (DeviceState *)object_dynamic_cast(OBJECT(obj),
+                                                          "device");
+
+    if (dev == NULL) {
+        return 0;
+    }
 
     if (dev->realized && object_property_get_bool(obj, "hotpluggable", NULL)) {
         *list = g_slist_append(*list, dev);
-- 
1.9.3