diff --git a/block.c b/block.c
index 7d1eb847a4..a921066d4d 100644
--- a/block.c
+++ b/block.c
@@ -1069,6 +1069,7 @@ int refresh_total_sectors(BlockDriverState *bs, int64_t hint)
 static void bdrv_join_options(BlockDriverState *bs, QDict *options,
                               QDict *old_options)
 {
+    g_assert(qemu_in_main_thread());
     if (bs->drv && bs->drv->bdrv_join_options) {
         bs->drv->bdrv_join_options(options, old_options);
     } else {
@@ -1561,6 +1562,7 @@ static int bdrv_open_driver(BlockDriverState *bs, BlockDriver *drv,
 {
     Error *local_err = NULL;
     int i, ret;
+    g_assert(qemu_in_main_thread());
 
     bdrv_assign_node_name(bs, node_name, &local_err);
     if (local_err) {
@@ -1932,6 +1934,8 @@ static int bdrv_fill_options(QDict **options, const char *filename,
     BlockDriver *drv = NULL;
     Error *local_err = NULL;
 
+    g_assert(qemu_in_main_thread());
+
     /*
      * Caution: while qdict_get_try_str() is fine, getting non-string
      * types would require more care.  When @options come from
@@ -2125,6 +2129,7 @@ static void bdrv_child_perm(BlockDriverState *bs, BlockDriverState *child_bs,
                             uint64_t *nperm, uint64_t *nshared)
 {
     assert(bs->drv && bs->drv->bdrv_child_perm);
+    g_assert(qemu_in_main_thread());
     bs->drv->bdrv_child_perm(bs, c, role, reopen_queue,
                              parent_perm, parent_shared,
                              nperm, nshared);
@@ -2208,6 +2213,7 @@ static void bdrv_drv_set_perm_commit(void *opaque)
 {
     BlockDriverState *bs = opaque;
     uint64_t cumulative_perms, cumulative_shared_perms;
+    g_assert(qemu_in_main_thread());
 
     if (bs->drv->bdrv_set_perm) {
         bdrv_get_cumulative_perm(bs, &cumulative_perms,
@@ -2219,6 +2225,7 @@ static void bdrv_drv_set_perm_commit(void *opaque)
 static void bdrv_drv_set_perm_abort(void *opaque)
 {
     BlockDriverState *bs = opaque;
+    g_assert(qemu_in_main_thread());
 
     if (bs->drv->bdrv_abort_perm_update) {
         bs->drv->bdrv_abort_perm_update(bs);
@@ -2234,6 +2241,7 @@ static int bdrv_drv_set_perm(BlockDriverState *bs, uint64_t perm,
                              uint64_t shared_perm, Transaction *tran,
                              Error **errp)
 {
+    g_assert(qemu_in_main_thread());
     if (!bs->drv) {
         return 0;
     }
@@ -4198,6 +4206,7 @@ int bdrv_reopen_multiple(BlockReopenQueue *bs_queue, Error **errp)
 
     assert(qemu_get_current_aio_context() == qemu_get_aio_context());
     assert(bs_queue != NULL);
+    g_assert(qemu_in_main_thread());
 
     QTAILQ_FOREACH(bs_entry, bs_queue, entry) {
         ctx = bdrv_get_aio_context(bs_entry->state.bs);
@@ -4461,6 +4470,7 @@ static int bdrv_reopen_prepare(BDRVReopenState *reopen_state,
 
     assert(reopen_state != NULL);
     assert(reopen_state->bs->drv != NULL);
+    g_assert(qemu_in_main_thread());
     drv = reopen_state->bs->drv;
 
     /* This function and each driver's bdrv_reopen_prepare() remove
@@ -4671,6 +4681,7 @@ static void bdrv_reopen_commit(BDRVReopenState *reopen_state)
     bs = reopen_state->bs;
     drv = bs->drv;
     assert(drv != NULL);
+    g_assert(qemu_in_main_thread());
 
     /* If there are any driver level actions to take */
     if (drv->bdrv_reopen_commit) {
@@ -4712,6 +4723,7 @@ static void bdrv_reopen_abort(BDRVReopenState *reopen_state)
     assert(reopen_state != NULL);
     drv = reopen_state->bs->drv;
     assert(drv != NULL);
+    g_assert(qemu_in_main_thread());
 
     if (drv->bdrv_reopen_abort) {
         drv->bdrv_reopen_abort(reopen_state);
@@ -4725,6 +4737,7 @@ static void bdrv_close(BlockDriverState *bs)
     BdrvChild *child, *next;
 
     assert(!bs->refcnt);
+    g_assert(qemu_in_main_thread());
 
     bdrv_drained_begin(bs); /* complete I/O */
     bdrv_flush(bs);
@@ -6409,6 +6422,7 @@ static int bdrv_inactivate_recurse(BlockDriverState *bs)
 {
     BdrvChild *child, *parent;
     int ret;
+    g_assert(qemu_in_main_thread());
 
     if (!bs->drv) {
         return -ENOMEDIUM;
@@ -6911,6 +6925,7 @@ static void bdrv_detach_aio_context(BlockDriverState *bs)
     BdrvAioNotifier *baf, *baf_tmp;
 
     assert(!bs->walking_aio_notifiers);
+    g_assert(qemu_in_main_thread());
     bs->walking_aio_notifiers = true;
     QLIST_FOREACH_SAFE(baf, &bs->aio_notifiers, list, baf_tmp) {
         if (baf->deleted) {
@@ -6938,6 +6953,7 @@ static void bdrv_attach_aio_context(BlockDriverState *bs,
                                     AioContext *new_context)
 {
     BdrvAioNotifier *ban, *ban_tmp;
+    g_assert(qemu_in_main_thread());
 
     if (bs->quiesce_counter) {
         aio_disable_external(new_context);
