virtio-ccw: move virtio_ccw_stop_ioeventfd to virtio_ccw_busdev_unplug

Similar to the PCI bug that prompted these patches, virtio-ccw will
segfault after the reworking of hotplug/hot-unplug.  Prepare for
this by moving virtio_ccw_stop_ioeventfd to before the freeing
of the proxy device.

A better place for this could be the device_unplugged callback
for the virtio-ccw bus.  However, we do not yet have a callback
that works: this patch avoids the problem while leaving the tree
bisectable.

Cc: qemu-stable@nongnu.org
Reported-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Suggested-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Acked-by: Andreas Faerber <afaerber@suse.de>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
(cherry picked from commit 0b81c1ef5c677c2a07be5f8bf0dfe2c62ef52115)

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

diff --git a/hw/s390x/virtio-ccw.c b/hw/s390x/virtio-ccw.c
index f93a81c7cdf194e8ba99a81d5855cfb9d2802744..e8b4547409537afb023b3ee84b1507d1acf2796f 100644 (file)
--- a/hw/s390x/virtio-ccw.c
+++ b/hw/s390x/virtio-ccw.c
@@ -631,7 +631,6 @@ static int virtio_ccw_exit(VirtioCcwDevice *dev)
 {
     SubchDev *sch = dev->sch;
 
-    virtio_ccw_stop_ioeventfd(dev);
     if (sch) {
         css_subch_assign(sch->cssid, sch->ssid, sch->schid, sch->devno, NULL);
         g_free(sch);
@@ -1228,6 +1227,8 @@ static int virtio_ccw_busdev_unplug(DeviceState *dev)
     VirtioCcwDevice *_dev = (VirtioCcwDevice *)dev;
     SubchDev *sch = _dev->sch;
 
+    virtio_ccw_stop_ioeventfd(_dev);
+
     /*
      * We should arrive here only for device_del, since we don't support
      * direct hot(un)plug of channels, but only through virtio.