From 3959d54c0bd5c92fe0a5e33fedb0595723efc23b Mon Sep 17 00:00:00 2001
From: Cuong Manh Le <cuong.manhle.vn@gmail.com>
Date: Sat, 20 Jul 2024 00:55:15 +0700
Subject: [PATCH] runtime: mark lockWithRankMayAcquire as nosplit

The function is called in nosplit context already.

Fixes #68525

Change-Id: I8b9e324335b7c605d5a20cacdd58df09b7a7cf52
Reviewed-on: https://go-review.googlesource.com/c/go/+/599675
Reviewed-by: Cherry Mui <cherryyz@google.com>
Reviewed-by: Michael Knyszek <mknyszek@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Auto-Submit: Cuong Manh Le <cuong.manhle.vn@gmail.com>
---
 src/runtime/lockrank_off.go  |  3 +++
 test/fixedbugs/issue68525.go | 13 +++++++++++++
 2 files changed, 16 insertions(+)
 create mode 100644 test/fixedbugs/issue68525.go

diff --git a/src/runtime/lockrank_off.go b/src/runtime/lockrank_off.go
index edeb265f43..18aef6bd2b 100644
--- a/src/runtime/lockrank_off.go
+++ b/src/runtime/lockrank_off.go
@@ -42,6 +42,9 @@ func releaseLockRankAndM(rank lockRank) {
 	releasem(getg().m)
 }
 
+// This function may be called in nosplit context and thus must be nosplit.
+//
+//go:nosplit
 func lockWithRankMayAcquire(l *mutex, rank lockRank) {
 }
 
diff --git a/test/fixedbugs/issue68525.go b/test/fixedbugs/issue68525.go
new file mode 100644
index 0000000000..e33de38be6
--- /dev/null
+++ b/test/fixedbugs/issue68525.go
@@ -0,0 +1,13 @@
+// run -gcflags='all=-N -l'
+
+// Copyright 2024 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package main
+
+import "os"
+
+func main() {
+	os.OpenFile(os.DevNull, os.O_WRONLY, 0)
+}
-- 
2.48.1