Right after main_loop ends, we release various things but keep iothread
alive. The latter is not prepared to the sudden change of resources.
Specifically, after bdrv_close_all(), virtio-scsi dataplane get a
surprise at the empty BlockBackend:
(gdb) bt
at /usr/src/debug/qemu-2.6.0/hw/scsi/virtio-scsi.c:543
at /usr/src/debug/qemu-2.6.0/hw/scsi/virtio-scsi.c:577
It is because the d->conf.blk->root is set to NULL, then
blk_get_aio_context() returns qemu_aio_context, whereas s->ctx is still
pointing to the iothread:
hw/scsi/virtio-scsi.c:543:
if (s->dataplane_started) {
assert(blk_get_aio_context(d->conf.blk) == s->ctx);
}
To fix this, let's stop iothreads before doing bdrv_close_all().
Cc: qemu-stable@nongnu.org
Signed-off-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Message-id: 1473326931-9699-1-git-send-email-famz@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
dce8921b2b