[PULL v2 05/16] virtio: Add corresponding memory_listener_unregister to unrealize

[Michael S. Tsirkin]

From: Eugenio Pérez <eperezma@redhat.com>

Address space is destroyed without proper removal of its listeners with
current code. They are expected to be removed in
virtio_device_instance_finalize [1], but qemu calls it through
object_deinit, after address_space_destroy call through
device_set_realized [2].

Move it to virtio_device_unrealize, called before device_set_realized
[3] and making it symmetric with memory_listener_register in
virtio_device_realize.

v2: Delete no-op call of virtio_device_instance_finalize.
    Add backtraces.

[1]

 #0  virtio_device_instance_finalize (obj=0x555557de5120)
     at /home/qemu/include/hw/virtio/virtio.h:71
 #1  0x0000555555b703c9 in object_deinit (type=0x555556639860,
      obj=<optimized out>) at ../qom/object.c:671
 #2  object_finalize (data=0x555557de5120) at ../qom/object.c:685
 #3  object_unref (objptr=0x555557de5120) at ../qom/object.c:1184
 #4  0x0000555555b4de9d in bus_free_bus_child (kid=0x555557df0660)
     at ../hw/core/qdev.c:55
 #5  0x0000555555c65003 in call_rcu_thread (opaque=opaque@entry=0x0)
     at ../util/rcu.c:281

Queued by:

 #0  bus_remove_child (bus=0x555557de5098,
     child=child@entry=0x555557de5120) at ../hw/core/qdev.c:60
 #1  0x0000555555b4ee31 in device_unparent (obj=<optimized out>)
     at ../hw/core/qdev.c:984
 #2  0x0000555555b70465 in object_finalize_child_property (
     obj=<optimized out>, name=<optimized out>, opaque=0x555557de5120)
     at ../qom/object.c:1725
 #3  0x0000555555b6fa17 in object_property_del_child (
     child=0x555557de5120, obj=0x555557ddcf90) at ../qom/object.c:645
 #4  object_unparent (obj=0x555557de5120) at ../qom/object.c:664
 #5  0x0000555555b4c071 in bus_unparent (obj=<optimized out>)
     at ../hw/core/bus.c:147
 #6  0x0000555555b70465 in object_finalize_child_property (
     obj=<optimized out>, name=<optimized out>, opaque=0x555557de5098)
     at ../qom/object.c:1725
 #7  0x0000555555b6fa17 in object_property_del_child (
     child=0x555557de5098, obj=0x555557ddcf90) at ../qom/object.c:645
 #8  object_unparent (obj=0x555557de5098) at ../qom/object.c:664
 #9  0x0000555555b4ee19 in device_unparent (obj=<optimized out>)
     at ../hw/core/qdev.c:981
 #10 0x0000555555b70465 in object_finalize_child_property (
     obj=<optimized out>, name=<optimized out>, opaque=0x555557ddcf90)
     at ../qom/object.c:1725
 #11 0x0000555555b6fa17 in object_property_del_child (
     child=0x555557ddcf90, obj=0x55555685da10) at ../qom/object.c:645
 #12 object_unparent (obj=0x555557ddcf90) at ../qom/object.c:664
 #13 0x00005555558dc331 in pci_for_each_device_under_bus (
     opaque=<optimized out>, fn=<optimized out>, bus=<optimized out>)
     at ../hw/pci/pci.c:1654

[2]

Optimizer omits pci_qdev_unrealize, called by device_set_realized, and
do_pci_unregister_device, called by pci_qdev_unrealize and caller of
address_space_destroy.

 #0  address_space_destroy (as=0x555557ddd1b8)
     at ../softmmu/memory.c:2840
 #1  0x0000555555b4fc53 in device_set_realized (obj=0x555557ddcf90,
      value=<optimized out>, errp=0x7fffeea8f1e0)
     at ../hw/core/qdev.c:850
 #2  0x0000555555b6eaa6 in property_set_bool (obj=0x555557ddcf90,
      v=<optimized out>, name=<optimized out>, opaque=0x555556650ba0,
     errp=0x7fffeea8f1e0) at ../qom/object.c:2255
 #3  0x0000555555b70e07 in object_property_set (
      obj=obj@entry=0x555557ddcf90,
      name=name@entry=0x555555db99df "realized",
      v=v@entry=0x7fffe46b7500,
      errp=errp@entry=0x5555565bbf38 <error_abort>)
     at ../qom/object.c:1400
 #4  0x0000555555b73c5f in object_property_set_qobject (
      obj=obj@entry=0x555557ddcf90,
      name=name@entry=0x555555db99df "realized",
      value=value@entry=0x7fffe44f6180,
      errp=errp@entry=0x5555565bbf38 <error_abort>)
     at ../qom/qom-qobject.c:28
 #5  0x0000555555b71044 in object_property_set_bool (
      obj=0x555557ddcf90, name=0x555555db99df "realized",
      value=<optimized out>, errp=0x5555565bbf38 <error_abort>)
     at ../qom/object.c:1470
 #6  0x0000555555921cb7 in pcie_unplug_device (bus=<optimized out>,
      dev=0x555557ddcf90,
      opaque=<optimized out>) at /home/qemu/include/hw/qdev-core.h:17
 #7  0x00005555558dc331 in pci_for_each_device_under_bus (
      opaque=<optimized out>, fn=<optimized out>,
      bus=<optimized out>) at ../hw/pci/pci.c:1654

[3]

 #0  virtio_device_unrealize (dev=0x555557de5120)
     at ../hw/virtio/virtio.c:3680
 #1  0x0000555555b4fc63 in device_set_realized (obj=0x555557de5120,
     value=<optimized out>, errp=0x7fffee28df90)
     at ../hw/core/qdev.c:850
 #2  0x0000555555b6eab6 in property_set_bool (obj=0x555557de5120,
     v=<optimized out>, name=<optimized out>, opaque=0x555556650ba0,
     errp=0x7fffee28df90) at ../qom/object.c:2255
 #3  0x0000555555b70e17 in object_property_set (
     obj=obj@entry=0x555557de5120,
     name=name@entry=0x555555db99ff "realized",
     v=v@entry=0x7ffdd8035040,
     errp=errp@entry=0x5555565bbf38 <error_abort>)
     at ../qom/object.c:1400
 #4  0x0000555555b73c6f in object_property_set_qobject (
     obj=obj@entry=0x555557de5120,
     name=name@entry=0x555555db99ff "realized",
     value=value@entry=0x7ffdd8035020,
     errp=errp@entry=0x5555565bbf38 <error_abort>)
     at ../qom/qom-qobject.c:28
 #5  0x0000555555b71054 in object_property_set_bool (
     obj=0x555557de5120, name=name@entry=0x555555db99ff "realized",
     value=value@entry=false, errp=0x5555565bbf38 <error_abort>)
     at ../qom/object.c:1470
 #6  0x0000555555b4edc5 in qdev_unrealize (dev=<optimized out>)
     at ../hw/core/qdev.c:403
 #7  0x0000555555b4c2a9 in bus_set_realized (obj=<optimized out>,
     value=<optimized out>, errp=<optimized out>)
     at ../hw/core/bus.c:204
 #8  0x0000555555b6eab6 in property_set_bool (obj=0x555557de5098,
     v=<optimized out>, name=<optimized out>, opaque=0x555557df04c0,
     errp=0x7fffee28e0a0) at ../qom/object.c:2255
 #9  0x0000555555b70e17 in object_property_set (
     obj=obj@entry=0x555557de5098,
     name=name@entry=0x555555db99ff "realized",
     v=v@entry=0x7ffdd8034f50,
     errp=errp@entry=0x5555565bbf38 <error_abort>)
     at ../qom/object.c:1400
 #10 0x0000555555b73c6f in object_property_set_qobject (
     obj=obj@entry=0x555557de5098,
     name=name@entry=0x555555db99ff "realized",
     value=value@entry=0x7ffdd8020630,
     errp=errp@entry=0x5555565bbf38 <error_abort>)
     at ../qom/qom-qobject.c:28
 #11 0x0000555555b71054 in object_property_set_bool (
     obj=obj@entry=0x555557de5098,
     name=name@entry=0x555555db99ff "realized",
     value=value@entry=false, errp=0x5555565bbf38 <error_abort>)
     at ../qom/object.c:1470
 #12 0x0000555555b4c725 in qbus_unrealize (
     bus=bus@entry=0x555557de5098) at ../hw/core/bus.c:178
 #13 0x0000555555b4fc00 in device_set_realized (obj=0x555557ddcf90,
     value=<optimized out>, errp=0x7fffee28e1e0)
     at ../hw/core/qdev.c:844
 #14 0x0000555555b6eab6 in property_set_bool (obj=0x555557ddcf90,
     v=<optimized out>, name=<optimized out>, opaque=0x555556650ba0,
     errp=0x7fffee28e1e0) at ../qom/object.c:2255
 #15 0x0000555555b70e17 in object_property_set (
     obj=obj@entry=0x555557ddcf90,
     name=name@entry=0x555555db99ff "realized",
     v=v@entry=0x7ffdd8020560,
     errp=errp@entry=0x5555565bbf38 <error_abort>)
     at ../qom/object.c:1400
 #16 0x0000555555b73c6f in object_property_set_qobject (
     obj=obj@entry=0x555557ddcf90,
     name=name@entry=0x555555db99ff "realized",
     value=value@entry=0x7ffdd8020540,
     errp=errp@entry=0x5555565bbf38 <error_abort>)
     at ../qom/qom-qobject.c:28
 #17 0x0000555555b71054 in object_property_set_bool (
     obj=0x555557ddcf90, name=0x555555db99ff "realized",
     value=<optimized out>, errp=0x5555565bbf38 <error_abort>)
     at ../qom/object.c:1470
 #18 0x0000555555921cb7 in pcie_unplug_device (bus=<optimized out>,
     dev=0x555557ddcf90, opaque=<optimized out>)
     at /home/qemu/include/hw/qdev-core.h:17
 #19 0x00005555558dc331 in pci_for_each_device_under_bus (
     opaque=<optimized out>, fn=<optimized out>, bus=<optimized out>)
     at ../hw/pci/pci.c:1654

Fixes: c611c76417f ("virtio: add MemoryListener to cache ring translations")
Buglink: https://bugs.launchpad.net/qemu/+bug/1912846
Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
Message-Id: <20210125192505.390554-1-eperezma@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
 hw/virtio/virtio.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c
index b308026596..1fd1917ca0 100644
--- a/hw/virtio/virtio.c
+++ b/hw/virtio/virtio.c
@@ -3680,6 +3680,7 @@ static void virtio_device_unrealize(DeviceState *dev)
     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
     VirtioDeviceClass *vdc = VIRTIO_DEVICE_GET_CLASS(dev);
 
+    memory_listener_unregister(&vdev->listener);
     virtio_bus_device_unplugged(vdev);
 
     if (vdc->unrealize != NULL) {
@@ -3710,7 +3711,6 @@ static void virtio_device_instance_finalize(Object *obj)
 {
     VirtIODevice *vdev = VIRTIO_DEVICE(obj);
 
-    memory_listener_unregister(&vdev->listener);
     virtio_device_free_virtqueues(vdev);
 
     g_free(vdev->config);
-- 
MST