From 30886390c2a59a24c23229f434453ca9ae247962 Mon Sep 17 00:00:00 2001
From: Ian Lance Taylor <iant@golang.org>
Date: Wed, 19 Apr 2023 14:16:37 -0700
Subject: [PATCH] runtime: in __tsan_fini tell scheduler we are entering non-Go
 code

__tsan_fini will call exit which will call destructors which
may in principle call back into Go functions. Prepare the scheduler
by calling entersyscall before __tsan_fini.

Fixes #59711

Change-Id: Ic4df8fba3014bafa516739408ccfc30aba4f22ad
Reviewed-on: https://go-review.googlesource.com/c/go/+/486615
Reviewed-by: Michael Pratt <mpratt@google.com>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Auto-Submit: Ian Lance Taylor <iant@google.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Run-TryBot: Ian Lance Taylor <iant@google.com>
---
 src/runtime/crash_cgo_test.go                 | 37 +++++++++++++++++++
 src/runtime/race.go                           |  7 ++++
 src/runtime/testdata/testprogcgo/destructor.c | 22 +++++++++++
 .../testdata/testprogcgo/destructor.go        | 23 ++++++++++++
 4 files changed, 89 insertions(+)
 create mode 100644 src/runtime/testdata/testprogcgo/destructor.c
 create mode 100644 src/runtime/testdata/testprogcgo/destructor.go

diff --git a/src/runtime/crash_cgo_test.go b/src/runtime/crash_cgo_test.go
index c6c018ccdf..1d8d874ca1 100644
--- a/src/runtime/crash_cgo_test.go
+++ b/src/runtime/crash_cgo_test.go
@@ -9,6 +9,7 @@ package runtime_test
 import (
 	"fmt"
 	"internal/goos"
+	"internal/platform"
 	"internal/testenv"
 	"os"
 	"os/exec"
@@ -777,3 +778,39 @@ func TestCgoSigfwd(t *testing.T) {
 		t.Fatalf("expected %q, but got:\n%s", want, got)
 	}
 }
+
+func TestDestructorCallback(t *testing.T) {
+	t.Parallel()
+	got := runTestProg(t, "testprogcgo", "DestructorCallback")
+	if want := "OK\n"; got != want {
+		t.Errorf("expected %q, but got:\n%s", want, got)
+	}
+}
+
+func TestDestructorCallbackRace(t *testing.T) {
+	// This test requires building with -race,
+	// so it's somewhat slow.
+	if testing.Short() {
+		t.Skip("skipping test in -short mode")
+	}
+
+	if !platform.RaceDetectorSupported(runtime.GOOS, runtime.GOARCH) {
+		t.Skipf("skipping on %s/%s because race detector not supported", runtime.GOOS, runtime.GOARCH)
+	}
+
+	t.Parallel()
+
+	exe, err := buildTestProg(t, "testprogcgo", "-race")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	got, err := testenv.CleanCmdEnv(exec.Command(exe, "DestructorCallback")).CombinedOutput()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if want := "OK\n"; string(got) != want {
+		t.Errorf("expected %q, but got:\n%s", want, got)
+	}
+}
diff --git a/src/runtime/race.go b/src/runtime/race.go
index f7e99fd940..7c7b78c145 100644
--- a/src/runtime/race.go
+++ b/src/runtime/race.go
@@ -407,9 +407,16 @@ func racefini() {
 	// already held it's assumed that the first caller exits the program
 	// so other calls can hang forever without an issue.
 	lock(&raceFiniLock)
+
+	// __tsan_fini will run C atexit functions and C++ destructors,
+	// which can theoretically call back into Go.
+	// Tell the scheduler we entering external code.
+	entersyscall()
+
 	// We're entering external code that may call ExitProcess on
 	// Windows.
 	osPreemptExtEnter(getg().m)
+
 	racecall(&__tsan_fini, 0, 0, 0, 0)
 }
 
diff --git a/src/runtime/testdata/testprogcgo/destructor.c b/src/runtime/testdata/testprogcgo/destructor.c
new file mode 100644
index 0000000000..8604d81570
--- /dev/null
+++ b/src/runtime/testdata/testprogcgo/destructor.c
@@ -0,0 +1,22 @@
+// Copyright 2023 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.
+
+#include "_cgo_export.h"
+
+static void callDestructorCallback() {
+	GoDestructorCallback();
+}
+
+static void (*destructorFn)(void);
+
+void registerDestructor() {
+	destructorFn = callDestructorCallback;
+}
+
+__attribute__((destructor))
+static void destructor() {
+	if (destructorFn) {
+		destructorFn();
+	}
+}
diff --git a/src/runtime/testdata/testprogcgo/destructor.go b/src/runtime/testdata/testprogcgo/destructor.go
new file mode 100644
index 0000000000..49529f09bf
--- /dev/null
+++ b/src/runtime/testdata/testprogcgo/destructor.go
@@ -0,0 +1,23 @@
+// Copyright 2023 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
+
+// extern void registerDestructor();
+import "C"
+
+import "fmt"
+
+func init() {
+	register("DestructorCallback", DestructorCallback)
+}
+
+//export GoDestructorCallback
+func GoDestructorCallback() {
+}
+
+func DestructorCallback() {
+	C.registerDestructor()
+	fmt.Println("OK")
+}
-- 
2.48.1