From 08c8a416ea2fb7e2ef3abe76454c4a8dc5ae995a Mon Sep 17 00:00:00 2001
From: "github-actions[bot]"
 <41898282+github-actions[bot]@users.noreply.github.com>
Date: Fri, 6 Dec 2024 16:25:33 +0800
Subject: [PATCH] branch-2.1: [fix](runtime_profile) fix race condition in
 to_thrift #45047 (#45099)

Cherry-picked from #45047

Co-authored-by: Kaijie Chen <chenkaijie@selectdb.com>
---
 be/src/util/runtime_profile.cpp | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/be/src/util/runtime_profile.cpp b/be/src/util/runtime_profile.cpp
index 782009d443..93f1406f2a 100644
--- a/be/src/util/runtime_profile.cpp
+++ b/be/src/util/runtime_profile.cpp
@@ -576,8 +576,6 @@ void RuntimeProfile::to_thrift(TRuntimeProfileTree* tree) {
 }
 
 void RuntimeProfile::to_thrift(std::vector<TRuntimeProfileNode>* nodes) {
-    nodes->reserve(nodes->size() + _children.size());
-
     int index = nodes->size();
     nodes->push_back(TRuntimeProfileNode());
     TRuntimeProfileNode& node = (*nodes)[index];
@@ -607,10 +605,13 @@ void RuntimeProfile::to_thrift(std::vector<TRuntimeProfileNode>* nodes) {
 
     ChildVector children;
     {
+        // _children may be modified during to_thrift(),
+        // so we have to lock and copy _children to avoid race condition
         std::lock_guard<std::mutex> l(_children_lock);
         children = _children;
     }
     node.num_children = children.size();
+    nodes->reserve(nodes->size() + children.size());
 
     for (int i = 0; i < children.size(); ++i) {
         int child_idx = nodes->size();