The function reads the parents list, so it needs to hold the graph lock.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Message-ID: <20230911094620.45040-19-kwolf@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 block.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/block.c b/block.c
index e024a6ccec..8e589bb2e4 100644
--- a/block.c
+++ b/block.c
@@ -7688,17 +7688,21 @@ static bool bdrv_change_aio_context(BlockDriverState *bs, AioContext *ctx,
         return true;
     }
 
+    bdrv_graph_rdlock_main_loop();
     QLIST_FOREACH(c, &bs->parents, next_parent) {
         if (!bdrv_parent_change_aio_context(c, ctx, visited, tran, errp)) {
+            bdrv_graph_rdunlock_main_loop();
             return false;
         }
     }
 
     QLIST_FOREACH(c, &bs->children, next) {
         if (!bdrv_child_change_aio_context(c, ctx, visited, tran, errp)) {
+            bdrv_graph_rdunlock_main_loop();
             return false;
         }
     }
+    bdrv_graph_rdunlock_main_loop();
 
     state = g_new(BdrvStateSetAioContext, 1);
     *state = (BdrvStateSetAioContext) {
-- 
2.41.0