From ef64bc1e0ac036a94b1ea358e4ea55c447ed684a Mon Sep 17 00:00:00 2001
From: altman08 <936396749@qq.com>
Date: Fri, 17 Jul 2026 18:45:26 +0800
Subject: [PATCH] bthread: use BAIDU_GET_VOLATILE_THREAD_LOCAL to access
 tls_unique_user_ptr in sched_to

tls_unique_user_ptr was read directly without going through the
BAIDU_GET_VOLATILE_THREAD_LOCAL macro in TaskGroup::sched_to, while
the paired write later in the same function correctly used
BAIDU_SET_VOLATILE_THREAD_LOCAL. sched_to contains jump_stack, a
suspend-point where GCC (aarch64) and Clang may incorrectly cache
the address of a thread_local variable, which is exactly the hazard
BAIDU_GET_VOLATILE_THREAD_LOCAL is designed to avoid. Fix the read to
use the macro for consistency and correctness.
---
 src/bthread/task_group.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/bthread/task_group.cpp b/src/bthread/task_group.cpp
index e54f947542..72a6b91836 100644
--- a/src/bthread/task_group.cpp
+++ b/src/bthread/task_group.cpp
@@ -817,7 +817,7 @@ void TaskGroup::sched_to(TaskGroup** pg, TaskMeta* next_meta) {
 #endif
     // Save errno so that errno is bthread-specific.
     int saved_errno = errno;
-    void* saved_unique_user_ptr = tls_unique_user_ptr;
+    void* saved_unique_user_ptr = BAIDU_GET_VOLATILE_THREAD_LOCAL(tls_unique_user_ptr);
 
     TaskMeta* const cur_meta = g->_cur_meta;
     int64_t now = butil::cpuwide_time_ns();