diff --git a/migration/ram.c b/migration/ram.c
index b5d03f85ab..f69d8d42b0 100644
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -3814,6 +3814,7 @@ void colo_flush_ram_cache(void)
     unsigned long offset = 0;
 
     memory_global_dirty_log_sync();
+    qemu_mutex_lock(&ram_state->bitmap_mutex);
     WITH_RCU_READ_LOCK_GUARD() {
         RAMBLOCK_FOREACH_NOT_IGNORED(block) {
             ramblock_sync_dirty_bitmap(ram_state, block);
@@ -3848,6 +3849,7 @@ void colo_flush_ram_cache(void)
             }
         }
     }
+    qemu_mutex_unlock(&ram_state->bitmap_mutex);
     trace_colo_flush_ram_cache_end();
 }