diff --git a/block/backup.c b/block/backup.c
index 581269b29a..f87f8d539b 100644
--- a/block/backup.c
+++ b/block/backup.c
@@ -489,7 +489,6 @@ void backup_start(BlockDriverState *bs, BlockDriverState *target,
 
     assert(bs);
     assert(target);
-    assert(cb);
 
     if (bs == target) {
         error_setg(errp, "Source and target cannot be the same");
diff --git a/blockjob.c b/blockjob.c
index 90c4e262b0..205da9df4e 100644
--- a/blockjob.c
+++ b/blockjob.c
@@ -110,6 +110,7 @@ void *block_job_create(const BlockJobDriver *driver, BlockDriverState *bs,
     BlockBackend *blk;
     BlockJob *job;
 
+    assert(cb);
     if (bs->job) {
         error_setg(errp, QERR_DEVICE_IN_USE, bdrv_get_device_name(bs));
         return NULL;