virtio-blk: fix unplug + virsh reboot

virtio-blk registers a vmstate change handler. Unfortunately this
handler is not unregistered on unplug, leading to some random
crashes if the system is restarted, e.g. via virsh reboot.
Lets unregister the vmstate change handler if the device is removed.

Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
(cherry picked from commit 69b302b2044a9a0f6d157d25b39a91ff7124c61f)

Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>

diff --git a/hw/virtio-blk.c b/hw/virtio-blk.c
index 34913ee40ee1e9478e8a1d10c0b1b92a11499477..f5e6ee90b62cd7542027509ee970be213a29f5bf 100644 (file)
--- a/hw/virtio-blk.c
+++ b/hw/virtio-blk.c
@@ -36,6 +36,7 @@ typedef struct VirtIOBlock
     VirtIOBlkConf *blk;
     unsigned short sector_mask;
     DeviceState *qdev;
+    VMChangeStateEntry *change;
 #ifdef CONFIG_VIRTIO_BLK_DATA_PLANE
     VirtIOBlockDataPlane *dataplane;
 #endif
@@ -681,7 +682,7 @@ VirtIODevice *virtio_blk_init(DeviceState *dev, VirtIOBlkConf *blk)
     }
 #endif
 
-    qemu_add_vm_change_state_handler(virtio_blk_dma_restart_cb, s);
+    s->change = qemu_add_vm_change_state_handler(virtio_blk_dma_restart_cb, s);
     s->qdev = dev;
     register_savevm(dev, "virtio-blk", virtio_blk_id++, 2,
                     virtio_blk_save, virtio_blk_load, s);
@@ -702,6 +703,7 @@ void virtio_blk_exit(VirtIODevice *vdev)
     virtio_blk_data_plane_destroy(s->dataplane);
     s->dataplane = NULL;
 #endif
+    qemu_del_vm_change_state_handler(s->change);
     unregister_savevm(s->qdev, "virtio-blk", s);
     blockdev_mark_auto_del(s->bs);
     virtio_cleanup(vdev);