diff --git a/block.c b/block.c
index 6ac4711..79bc9c0 100644
--- a/block.c
+++ b/block.c
@@ -7037,6 +7037,8 @@
         return;
     }
 
+    aio_context_acquire(qemu_get_aio_context());
+
     /* Create parameter list */
     create_opts = qemu_opts_append(create_opts, drv->create_opts);
     create_opts = qemu_opts_append(create_opts, proto_drv->create_opts);
@@ -7186,6 +7188,7 @@
     qemu_opts_del(opts);
     qemu_opts_free(create_opts);
     error_propagate(errp, local_err);
+    aio_context_release(qemu_get_aio_context());
 }
 
 AioContext *bdrv_get_aio_context(BlockDriverState *bs)
diff --git a/block/block-backend.c b/block/block-backend.c
index 2644766..1d89fab 100644
--- a/block/block-backend.c
+++ b/block/block-backend.c
@@ -452,7 +452,9 @@
     }
 
     blk = blk_new(qemu_get_aio_context(), perm, shared);
+    aio_context_acquire(qemu_get_aio_context());
     bs = bdrv_open(filename, reference, options, flags, errp);
+    aio_context_release(qemu_get_aio_context());
     if (!bs) {
         blk_unref(blk);
         return NULL;
diff --git a/block/qapi-sysemu.c b/block/qapi-sysemu.c
index cec3c1a..ef07151 100644
--- a/block/qapi-sysemu.c
+++ b/block/qapi-sysemu.c
@@ -362,7 +362,10 @@
         qdict_put_str(options, "driver", format);
     }
 
+    aio_context_acquire(qemu_get_aio_context());
     medium_bs = bdrv_open(filename, NULL, options, bdrv_flags, errp);
+    aio_context_release(qemu_get_aio_context());
+
     if (!medium_bs) {
         goto fail;
     }
diff --git a/blockdev.c b/blockdev.c
index 5d56b79..db2725f 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -662,6 +662,7 @@
 /* Takes the ownership of bs_opts */
 BlockDriverState *bds_tree_init(QDict *bs_opts, Error **errp)
 {
+    BlockDriverState *bs;
     int bdrv_flags = 0;
 
     GLOBAL_STATE_CODE();
@@ -676,7 +677,11 @@
         bdrv_flags |= BDRV_O_INACTIVE;
     }
 
-    return bdrv_open(NULL, NULL, bs_opts, bdrv_flags, errp);
+    aio_context_acquire(qemu_get_aio_context());
+    bs = bdrv_open(NULL, NULL, bs_opts, bdrv_flags, errp);
+    aio_context_release(qemu_get_aio_context());
+
+    return bs;
 }
 
 void blockdev_close_all_bdrv_states(void)
@@ -1480,14 +1485,20 @@
         }
         qdict_put_str(options, "driver", format);
     }
+    aio_context_release(aio_context);
 
+    aio_context_acquire(qemu_get_aio_context());
     state->new_bs = bdrv_open(new_image_file, snapshot_ref, options, flags,
                               errp);
+    aio_context_release(qemu_get_aio_context());
+
     /* We will manually add the backing_hd field to the bs later */
     if (!state->new_bs) {
-        goto out;
+        return;
     }
 
+    aio_context_acquire(aio_context);
+
     /*
      * Allow attaching a backing file to an overlay that's already in use only
      * if the parents don't assume that they are already seeing a valid image.
@@ -1732,15 +1743,18 @@
     if (format) {
         qdict_put_str(options, "driver", format);
     }
+    aio_context_release(aio_context);
 
+    aio_context_acquire(qemu_get_aio_context());
     target_bs = bdrv_open(backup->target, NULL, options, flags, errp);
+    aio_context_release(qemu_get_aio_context());
+
     if (!target_bs) {
-        goto out;
+        return;
     }
 
     /* Honor bdrv_try_change_aio_context() context acquisition requirements. */
     old_context = bdrv_get_aio_context(target_bs);
-    aio_context_release(aio_context);
     aio_context_acquire(old_context);
 
     ret = bdrv_try_change_aio_context(target_bs, aio_context, NULL, errp);
@@ -3066,13 +3080,17 @@
     if (format) {
         qdict_put_str(options, "driver", format);
     }
+    aio_context_release(aio_context);
 
     /* Mirroring takes care of copy-on-write using the source's backing
      * file.
      */
+    aio_context_acquire(qemu_get_aio_context());
     target_bs = bdrv_open(arg->target, NULL, options, flags, errp);
+    aio_context_release(qemu_get_aio_context());
+
     if (!target_bs) {
-        goto out;
+        return;
     }
 
     zero_target = (arg->sync == MIRROR_SYNC_MODE_FULL &&
@@ -3082,7 +3100,6 @@
 
     /* Honor bdrv_try_change_aio_context() context acquisition requirements. */
     old_context = bdrv_get_aio_context(target_bs);
-    aio_context_release(aio_context);
     aio_context_acquire(old_context);
 
     ret = bdrv_try_change_aio_context(target_bs, aio_context, NULL, errp);
diff --git a/qemu-nbd.c b/qemu-nbd.c
index 6ff4530..4276163 100644
--- a/qemu-nbd.c
+++ b/qemu-nbd.c
@@ -1071,7 +1071,11 @@
         qdict_put_str(raw_opts, "driver", "raw");
         qdict_put_str(raw_opts, "file", bs->node_name);
         qdict_put_int(raw_opts, "offset", dev_offset);
+
+        aio_context_acquire(qemu_get_aio_context());
         bs = bdrv_open(NULL, NULL, raw_opts, flags, &error_fatal);
+        aio_context_release(qemu_get_aio_context());
+
         blk_remove_bs(blk);
         blk_insert_bs(blk, bs, &error_fatal);
         bdrv_unref(bs);
diff --git a/tests/unit/test-block-iothread.c b/tests/unit/test-block-iothread.c
index 3a5e1eb..1b40e65 100644
--- a/tests/unit/test-block-iothread.c
+++ b/tests/unit/test-block-iothread.c
@@ -833,8 +833,11 @@
     qdict_put_str(options, "driver", "raw");
     qdict_put_str(options, "file", "base");
 
+    /* FIXME raw_open() should take ctx's lock internally */
     aio_context_acquire(ctx);
+    aio_context_acquire(main_ctx);
     filter = bdrv_open(NULL, NULL, options, BDRV_O_RDWR, &error_abort);
+    aio_context_release(main_ctx);
     aio_context_release(ctx);
 
     g_assert(blk_get_aio_context(blk) == ctx);