Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 migration/block.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/migration/block.c b/migration/block.c
index 2bcfcbfdf6..6ec6a1d6e6 100644
--- a/migration/block.c
+++ b/migration/block.c
@@ -311,10 +311,17 @@ static int mig_save_device_bulk(QEMUFile *f, BlkMigDevState *bmds)
     block_mig_state.submitted++;
     blk_mig_unlock();
 
+    /*
+     * The migration thread does not have an AioContext. Lock the BQL so that
+     * I/O runs in the main loop AioContext (see
+     * qemu_get_current_aio_context()).
+     */
+    qemu_mutex_lock_iothread();
     bdrv_reset_dirty_bitmap(bmds->dirty_bitmap, cur_sector * BDRV_SECTOR_SIZE,
                             nr_sectors * BDRV_SECTOR_SIZE);
     blk->aiocb = blk_aio_preadv(bb, cur_sector * BDRV_SECTOR_SIZE, &blk->qiov,
                                 0, blk_mig_read_cb, blk);
+    qemu_mutex_unlock_iothread();
 
     bmds->cur_sector = cur_sector + nr_sectors;
     return (bmds->cur_sector >= total_sectors);
-- 
2.43.0