qemu_savevm_state_complete_precopy() requires that BQL is held.

This fixes a crash when running with TCG accel.

Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Lukas Straub <lukasstraub2@web.de>
---
 migration/colo.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/migration/colo.c b/migration/colo.c
index dc7cfa81ef7db78e3ee372642de48567c5bc06eb..3297aa593cd9f87bf1013598464cc581a9d23531 100644
--- a/migration/colo.c
+++ b/migration/colo.c
@@ -455,9 +455,8 @@ static int colo_do_checkpoint_transaction(MigrationState *s,
 
     /* Note: device state is saved into buffer */
     ret = qemu_save_device_state(fb, &local_err);
-
-    bql_unlock();
     if (ret < 0) {
+        bql_unlock();
         goto out;
     }
 
@@ -471,6 +470,7 @@ static int colo_do_checkpoint_transaction(MigrationState *s,
      */
     qemu_savevm_state_complete_precopy_iterable(s->to_dst_file, false);
     qemu_savevm_state_end(s->to_dst_file);
+    bql_unlock();
 
     /*
      * We need the size of the VMstate data in Secondary side,

-- 
2.39.5