diff --git a/src/bthread/bthread.cpp b/src/bthread/bthread.cpp
index 0cbe628cda..dcd29c43dc 100644
--- a/src/bthread/bthread.cpp
+++ b/src/bthread/bthread.cpp
@@ -391,6 +391,10 @@ int bthread_setconcurrency_by_tag(int num, bthread_tag_t tag) {
     } else if (tag < BTHREAD_TAG_DEFAULT || tag >= FLAGS_task_group_ntags) {
         return EINVAL;
     }
+    if (num < BTHREAD_MIN_CONCURRENCY || num > BTHREAD_MAX_CONCURRENCY) {
+        LOG(ERROR) << "Invalid concurrency_by_tag=" << num;
+        return EINVAL;
+    }
     auto c = bthread::get_or_new_task_control();
     BAIDU_SCOPED_LOCK(bthread::g_task_control_mutex);
     auto ngroup = c->concurrency();