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 <[email protected]>
Reviewed-by: Michael Knyszek <[email protected]>
LUCI-TryBot-Result: Go LUCI <[email protected]>
Auto-Submit: Cuong Manh Le <[email protected]>

Author: cuonglm

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) {
 }
 

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)
+}