Initial commit: Go 1.23 release state

src/runtime/race/README

@@ -0,0 +1,17 @@
+runtime/race package contains the data race detector runtime library.
+It is based on ThreadSanitizer race detector, that is currently a part of
+the LLVM project (https://github.com/llvm/llvm-project/tree/main/compiler-rt).
+
+To update the .syso files use golang.org/x/build/cmd/racebuild.
+
+internal/amd64v1/race_darwin.syso built with LLVM 51bfeff0e4b0757ff773da6882f4d538996c9b04 and Go e7d582b55dda36e76ce4d0ce770139ca0915b7c5.
+internal/amd64v1/race_freebsd.syso built with LLVM 51bfeff0e4b0757ff773da6882f4d538996c9b04 and Go e7d582b55dda36e76ce4d0ce770139ca0915b7c5.
+internal/amd64v1/race_linux.syso built with LLVM 51bfeff0e4b0757ff773da6882f4d538996c9b04 and Go e7d582b55dda36e76ce4d0ce770139ca0915b7c5.
+internal/amd64v1/race_netbsd.syso built with LLVM 51bfeff0e4b0757ff773da6882f4d538996c9b04 and Go e7d582b55dda36e76ce4d0ce770139ca0915b7c5.
+internal/amd64v1/race_openbsd.syso built with LLVM fcf6ae2f070eba73074b6ec8d8281e54d29dbeeb and Go 8f2db14cd35bbd674cb2988a508306de6655e425.
+internal/amd64v1/race_windows.syso built with LLVM 51bfeff0e4b0757ff773da6882f4d538996c9b04 and Go e7d582b55dda36e76ce4d0ce770139ca0915b7c5.
+internal/amd64v3/race_linux.syso built with LLVM 51bfeff0e4b0757ff773da6882f4d538996c9b04 and Go e7d582b55dda36e76ce4d0ce770139ca0915b7c5.
+race_darwin_arm64.syso built with LLVM 51bfeff0e4b0757ff773da6882f4d538996c9b04 and Go e7d582b55dda36e76ce4d0ce770139ca0915b7c5.
+race_linux_arm64.syso built with LLVM 51bfeff0e4b0757ff773da6882f4d538996c9b04 and Go e7d582b55dda36e76ce4d0ce770139ca0915b7c5.
+race_linux_ppc64le.syso built with LLVM 51bfeff0e4b0757ff773da6882f4d538996c9b04 and Go e7d582b55dda36e76ce4d0ce770139ca0915b7c5.
+race_linux_s390x.syso built with LLVM 51bfeff0e4b0757ff773da6882f4d538996c9b04 and Go e7d582b55dda36e76ce4d0ce770139ca0915b7c5.

src/runtime/race/doc.go

@@ -0,0 +1,11 @@
+// Copyright 2013 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 race implements data race detection logic.
+// No public interface is provided.
+// For details about the race detector see
+// https://golang.org/doc/articles/race_detector.html
+package race
+
+//go:generate ./mkcgo.sh

src/runtime/race/internal/amd64v1/doc.go

@@ -0,0 +1,10 @@
+// Copyright 2022 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.
+
+// This package holds the race detector .syso for
+// amd64 architectures with GOAMD64<v3.
+
+//go:build amd64 && ((linux && !amd64.v3) || darwin || freebsd || netbsd || openbsd || windows)
+
+package amd64v1

src/runtime/race/internal/amd64v3/doc.go

@@ -0,0 +1,10 @@
+// Copyright 2022 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.
+
+// This package holds the race detector .syso for
+// amd64 architectures with GOAMD64>=v3.
+
+//go:build amd64 && linux && amd64.v3
+
+package amd64v3

src/runtime/race/mkcgo.sh

@@ -0,0 +1,20 @@
+#!/bin/bash
+
+hdr='
+// Copyright 2022 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.
+
+// Code generated by mkcgo.sh. DO NOT EDIT.
+
+//go:build race
+
+'
+
+convert() {
+	(echo "$hdr"; go tool cgo -dynpackage race -dynimport $1) | gofmt
+}
+
+convert race_darwin_arm64.syso >race_darwin_arm64.go
+convert internal/amd64v1/race_darwin.syso >race_darwin_amd64.go
+

src/runtime/race/output_test.go

@@ -0,0 +1,480 @@
+// Copyright 2013 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.
+
+//go:build race
+
+package race_test
+
+import (
+	"fmt"
+	"internal/testenv"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"regexp"
+	"runtime"
+	"strings"
+	"testing"
+)
+
+func TestOutput(t *testing.T) {
+	pkgdir := t.TempDir()
+	out, err := exec.Command(testenv.GoToolPath(t), "install", "-race", "-pkgdir="+pkgdir, "testing").CombinedOutput()
+	if err != nil {
+		t.Fatalf("go install -race: %v\n%s", err, out)
+	}
+
+	for _, test := range tests {
+		if test.goos != "" && test.goos != runtime.GOOS {
+			t.Logf("test %v runs only on %v, skipping: ", test.name, test.goos)
+			continue
+		}
+		dir := t.TempDir()
+		source := "main.go"
+		if test.run == "test" {
+			source = "main_test.go"
+		}
+		src := filepath.Join(dir, source)
+		f, err := os.Create(src)
+		if err != nil {
+			t.Fatalf("failed to create file: %v", err)
+		}
+		_, err = f.WriteString(test.source)
+		if err != nil {
+			f.Close()
+			t.Fatalf("failed to write: %v", err)
+		}
+		if err := f.Close(); err != nil {
+			t.Fatalf("failed to close file: %v", err)
+		}
+
+		cmd := exec.Command(testenv.GoToolPath(t), test.run, "-race", "-pkgdir="+pkgdir, src)
+		// GODEBUG spoils program output, GOMAXPROCS makes it flaky.
+		for _, env := range os.Environ() {
+			if strings.HasPrefix(env, "GODEBUG=") ||
+				strings.HasPrefix(env, "GOMAXPROCS=") ||
+				strings.HasPrefix(env, "GORACE=") {
+				continue
+			}
+			cmd.Env = append(cmd.Env, env)
+		}
+		cmd.Env = append(cmd.Env,
+			"GOMAXPROCS=1", // see comment in race_test.go
+			"GORACE="+test.gorace,
+		)
+		got, _ := cmd.CombinedOutput()
+		matched := false
+		for _, re := range test.re {
+			if regexp.MustCompile(re).MatchString(string(got)) {
+				matched = true
+				break
+			}
+		}
+		if !matched {
+			exp := fmt.Sprintf("expect:\n%v\n", test.re[0])
+			if len(test.re) > 1 {
+				exp = fmt.Sprintf("expected one of %d patterns:\n",
+					len(test.re))
+				for k, re := range test.re {
+					exp += fmt.Sprintf("pattern %d:\n%v\n", k, re)
+				}
+			}
+			t.Fatalf("failed test case %v, %sgot:\n%s",
+				test.name, exp, got)
+		}
+	}
+}
+
+var tests = []struct {
+	name   string
+	run    string
+	goos   string
+	gorace string
+	source string
+	re     []string
+}{
+	{"simple", "run", "", "atexit_sleep_ms=0", `
+package main
+import "time"
+var xptr *int
+var donechan chan bool
+func main() {
+	done := make(chan bool)
+	x := 0
+	startRacer(&x, done)
+	store(&x, 43)
+	<-done
+}
+func store(x *int, v int) {
+	*x = v
+}
+func startRacer(x *int, done chan bool) {
+	xptr = x
+	donechan = done
+	go racer()
+}
+func racer() {
+	time.Sleep(10*time.Millisecond)
+	store(xptr, 42)
+	donechan <- true
+}
+`, []string{`==================
+WARNING: DATA RACE
+Write at 0x[0-9,a-f]+ by goroutine [0-9]:
+  main\.store\(\)
+      .+/main\.go:14 \+0x[0-9,a-f]+
+  main\.racer\(\)
+      .+/main\.go:23 \+0x[0-9,a-f]+
+
+Previous write at 0x[0-9,a-f]+ by main goroutine:
+  main\.store\(\)
+      .+/main\.go:14 \+0x[0-9,a-f]+
+  main\.main\(\)
+      .+/main\.go:10 \+0x[0-9,a-f]+
+
+Goroutine [0-9] \(running\) created at:
+  main\.startRacer\(\)
+      .+/main\.go:19 \+0x[0-9,a-f]+
+  main\.main\(\)
+      .+/main\.go:9 \+0x[0-9,a-f]+
+==================
+Found 1 data race\(s\)
+exit status 66
+`}},
+
+	{"exitcode", "run", "", "atexit_sleep_ms=0 exitcode=13", `
+package main
+func main() {
+	done := make(chan bool)
+	x := 0; _ = x
+	go func() {
+		x = 42
+		done <- true
+	}()
+	x = 43
+	<-done
+}
+`, []string{`exit status 13`}},
+
+	{"strip_path_prefix", "run", "", "atexit_sleep_ms=0 strip_path_prefix=/main.", `
+package main
+func main() {
+	done := make(chan bool)
+	x := 0; _ = x
+	go func() {
+		x = 42
+		done <- true
+	}()
+	x = 43
+	<-done
+}
+`, []string{`
+      go:7 \+0x[0-9,a-f]+
+`}},
+
+	{"halt_on_error", "run", "", "atexit_sleep_ms=0 halt_on_error=1", `
+package main
+func main() {
+	done := make(chan bool)
+	x := 0; _ = x
+	go func() {
+		x = 42
+		done <- true
+	}()
+	x = 43
+	<-done
+}
+`, []string{`
+==================
+exit status 66
+`}},
+
+	{"test_fails_on_race", "test", "", "atexit_sleep_ms=0", `
+package main_test
+import "testing"
+func TestFail(t *testing.T) {
+	done := make(chan bool)
+	x := 0
+	_ = x
+	go func() {
+		x = 42
+		done <- true
+	}()
+	x = 43
+	<-done
+	t.Log(t.Failed())
+}
+`, []string{`
+==================
+--- FAIL: TestFail \([0-9.]+s\)
+.*testing.go:.*: race detected during execution of test
+.*main_test.go:14: true
+FAIL`}},
+
+	{"slicebytetostring_pc", "run", "", "atexit_sleep_ms=0", `
+package main
+func main() {
+	done := make(chan string)
+	data := make([]byte, 10)
+	go func() {
+		done <- string(data)
+	}()
+	data[0] = 1
+	<-done
+}
+`, []string{`
+  runtime\.slicebytetostring\(\)
+      .*/runtime/string\.go:.*
+  main\.main\.func1\(\)
+      .*/main.go:7`}},
+
+	// Test for https://golang.org/issue/33309
+	{"midstack_inlining_traceback", "run", "linux", "atexit_sleep_ms=0", `
+package main
+
+var x int
+var c chan int
+func main() {
+	c = make(chan int)
+	go f()
+	x = 1
+	<-c
+}
+
+func f() {
+	g(c)
+}
+
+func g(c chan int) {
+	h(c)
+}
+
+func h(c chan int) {
+	c <- x
+}
+`, []string{`==================
+WARNING: DATA RACE
+Read at 0x[0-9,a-f]+ by goroutine [0-9]:
+  main\.h\(\)
+      .+/main\.go:22 \+0x[0-9,a-f]+
+  main\.g\(\)
+      .+/main\.go:18 \+0x[0-9,a-f]+
+  main\.f\(\)
+      .+/main\.go:14 \+0x[0-9,a-f]+
+
+Previous write at 0x[0-9,a-f]+ by main goroutine:
+  main\.main\(\)
+      .+/main\.go:9 \+0x[0-9,a-f]+
+
+Goroutine [0-9] \(running\) created at:
+  main\.main\(\)
+      .+/main\.go:8 \+0x[0-9,a-f]+
+==================
+Found 1 data race\(s\)
+exit status 66
+`}},
+
+	// Test for https://golang.org/issue/17190
+	{"external_cgo_thread", "run", "linux", "atexit_sleep_ms=0", `
+package main
+
+/*
+#include <pthread.h>
+typedef struct cb {
+        int foo;
+} cb;
+extern void goCallback();
+static inline void *threadFunc(void *p) {
+	goCallback();
+	return 0;
+}
+static inline void startThread(cb* c) {
+	pthread_t th;
+	pthread_create(&th, 0, threadFunc, 0);
+}
+*/
+import "C"
+
+var done chan bool
+var racy int
+
+//export goCallback
+func goCallback() {
+	racy++
+	done <- true
+}
+
+func main() {
+	done = make(chan bool)
+	var c C.cb
+	C.startThread(&c)
+	racy++
+	<- done
+}
+`, []string{`==================
+WARNING: DATA RACE
+Read at 0x[0-9,a-f]+ by main goroutine:
+  main\.main\(\)
+      .*/main\.go:34 \+0x[0-9,a-f]+
+
+Previous write at 0x[0-9,a-f]+ by goroutine [0-9]:
+  main\.goCallback\(\)
+      .*/main\.go:27 \+0x[0-9,a-f]+
+  _cgoexp_[0-9a-z]+_goCallback\(\)
+      .*_cgo_gotypes\.go:[0-9]+ \+0x[0-9,a-f]+
+  _cgoexp_[0-9a-z]+_goCallback\(\)
+      <autogenerated>:1 \+0x[0-9,a-f]+
+
+Goroutine [0-9] \(running\) created at:
+  runtime\.newextram\(\)
+      .*/runtime/proc.go:[0-9]+ \+0x[0-9,a-f]+
+==================`,
+		`==================
+WARNING: DATA RACE
+Read at 0x[0-9,a-f]+ by .*:
+  main\..*
+      .*/main\.go:[0-9]+ \+0x[0-9,a-f]+(?s).*
+
+Previous write at 0x[0-9,a-f]+ by .*:
+  main\..*
+      .*/main\.go:[0-9]+ \+0x[0-9,a-f]+(?s).*
+
+Goroutine [0-9] \(running\) created at:
+  runtime\.newextram\(\)
+      .*/runtime/proc.go:[0-9]+ \+0x[0-9,a-f]+
+==================`}},
+	{"second_test_passes", "test", "", "atexit_sleep_ms=0", `
+package main_test
+import "testing"
+func TestFail(t *testing.T) {
+	done := make(chan bool)
+	x := 0
+	_ = x
+	go func() {
+		x = 42
+		done <- true
+	}()
+	x = 43
+	<-done
+}
+
+func TestPass(t *testing.T) {
+}
+`, []string{`
+==================
+--- FAIL: TestFail \([0-9.]+s\)
+.*testing.go:.*: race detected during execution of test
+FAIL`}},
+	{"mutex", "run", "", "atexit_sleep_ms=0", `
+package main
+import (
+	"sync"
+	"fmt"
+)
+func main() {
+	c := make(chan bool, 1)
+	threads := 1
+	iterations := 20000
+	data := 0
+	var wg sync.WaitGroup
+	for i := 0; i < threads; i++ {
+		wg.Add(1)
+		go func() {
+			defer wg.Done()
+			for i := 0; i < iterations; i++ {
+				c <- true
+				data += 1
+				<- c
+			}
+		}()
+	}
+	for i := 0; i < iterations; i++ {
+		c <- true
+		data += 1
+		<- c
+	}
+	wg.Wait()
+	if (data == iterations*(threads+1)) { fmt.Println("pass") }
+}`, []string{`pass`}},
+	// Test for https://github.com/golang/go/issues/37355
+	{"chanmm", "run", "", "atexit_sleep_ms=0", `
+package main
+import (
+	"sync"
+	"time"
+)
+func main() {
+	c := make(chan bool, 1)
+	var data uint64
+	var wg sync.WaitGroup
+	wg.Add(2)
+	c <- true
+	go func() {
+		defer wg.Done()
+		c <- true
+	}()
+	go func() {
+		defer wg.Done()
+		time.Sleep(time.Second)
+		<-c
+		data = 2
+	}()
+	data = 1
+	<-c
+	wg.Wait()
+	_ = data
+}
+`, []string{`==================
+WARNING: DATA RACE
+Write at 0x[0-9,a-f]+ by goroutine [0-9]:
+  main\.main\.func2\(\)
+      .*/main\.go:21 \+0x[0-9,a-f]+
+
+Previous write at 0x[0-9,a-f]+ by main goroutine:
+  main\.main\(\)
+      .*/main\.go:23 \+0x[0-9,a-f]+
+
+Goroutine [0-9] \(running\) created at:
+  main\.main\(\)
+      .*/main.go:[0-9]+ \+0x[0-9,a-f]+
+==================`}},
+	// Test symbolizing wrappers. Both (*T).f and main.gowrap1 are wrappers.
+	// go.dev/issue/60245
+	{"wrappersym", "run", "", "atexit_sleep_ms=0", `
+package main
+import "sync"
+var wg sync.WaitGroup
+var x int
+func main() {
+	f := (*T).f
+	wg.Add(2)
+	go f(new(T))
+	f(new(T))
+	wg.Wait()
+}
+type T struct{}
+func (t T) f() {
+	x = 42
+	wg.Done()
+}
+`, []string{`==================
+WARNING: DATA RACE
+Write at 0x[0-9,a-f]+ by goroutine [0-9]:
+  main\.T\.f\(\)
+      .*/main.go:15 \+0x[0-9,a-f]+
+  main\.\(\*T\)\.f\(\)
+      <autogenerated>:1 \+0x[0-9,a-f]+
+  main\.main\.gowrap1\(\)
+      .*/main.go:9 \+0x[0-9,a-f]+
+
+Previous write at 0x[0-9,a-f]+ by main goroutine:
+  main\.T\.f\(\)
+      .*/main.go:15 \+0x[0-9,a-f]+
+  main\.\(\*T\)\.f\(\)
+      <autogenerated>:1 \+0x[0-9,a-f]+
+  main\.main\(\)
+      .*/main.go:10 \+0x[0-9,a-f]+
+
+`}},
+}

src/runtime/race/race.go

@@ -0,0 +1,20 @@
+// Copyright 2012 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.
+
+//go:build race && ((linux && (amd64 || arm64 || ppc64le || s390x)) || ((freebsd || netbsd || openbsd || windows) && amd64))
+
+package race
+
+// This file merely ensures that we link in runtime/cgo in race build,
+// this in turn ensures that runtime uses pthread_create to create threads.
+// The prebuilt race runtime lives in race_GOOS_GOARCH.syso.
+// Calls to the runtime are done directly from src/runtime/race.go.
+
+// On darwin we always use system DLLs to create threads,
+// so we use race_darwin_$GOARCH.go to provide the syso-derived
+// symbol information without needing to invoke cgo.
+// This allows -race to be used on Mac systems without a C toolchain.
+
+// void __race_unused_func(void);
+import "C"

src/runtime/race/race_darwin_amd64.go

@@ -0,0 +1,108 @@
+// Copyright 2022 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.
+
+// Code generated by mkcgo.sh. DO NOT EDIT.
+
+//go:build race
+
+package race
+
+//go:cgo_import_dynamic _Block_object_assign _Block_object_assign ""
+//go:cgo_import_dynamic _Block_object_dispose _Block_object_dispose ""
+//go:cgo_import_dynamic _NSConcreteStackBlock _NSConcreteStackBlock ""
+//go:cgo_import_dynamic _NSGetArgv _NSGetArgv ""
+//go:cgo_import_dynamic _NSGetEnviron _NSGetEnviron ""
+//go:cgo_import_dynamic _NSGetExecutablePath _NSGetExecutablePath ""
+//go:cgo_import_dynamic __bzero __bzero ""
+//go:cgo_import_dynamic __error __error ""
+//go:cgo_import_dynamic __fork __fork ""
+//go:cgo_import_dynamic __mmap __mmap ""
+//go:cgo_import_dynamic __munmap __munmap ""
+//go:cgo_import_dynamic __stack_chk_fail __stack_chk_fail ""
+//go:cgo_import_dynamic __stack_chk_guard __stack_chk_guard ""
+//go:cgo_import_dynamic _dyld_get_image_header _dyld_get_image_header ""
+//go:cgo_import_dynamic _dyld_get_image_name _dyld_get_image_name ""
+//go:cgo_import_dynamic _dyld_get_image_vmaddr_slide _dyld_get_image_vmaddr_slide ""
+//go:cgo_import_dynamic _dyld_get_shared_cache_range _dyld_get_shared_cache_range ""
+//go:cgo_import_dynamic _dyld_get_shared_cache_uuid _dyld_get_shared_cache_uuid ""
+//go:cgo_import_dynamic _dyld_image_count _dyld_image_count ""
+//go:cgo_import_dynamic _exit _exit ""
+//go:cgo_import_dynamic _sanitizer_internal_memcpy _sanitizer_internal_memcpy ""
+//go:cgo_import_dynamic _sanitizer_internal_memmove _sanitizer_internal_memmove ""
+//go:cgo_import_dynamic _sanitizer_internal_memset _sanitizer_internal_memset ""
+//go:cgo_import_dynamic abort abort ""
+//go:cgo_import_dynamic arc4random_buf arc4random_buf ""
+//go:cgo_import_dynamic close close ""
+//go:cgo_import_dynamic dlsym dlsym ""
+//go:cgo_import_dynamic dup dup ""
+//go:cgo_import_dynamic dup2 dup2 ""
+//go:cgo_import_dynamic dyld_shared_cache_iterate_text dyld_shared_cache_iterate_text ""
+//go:cgo_import_dynamic execve execve ""
+//go:cgo_import_dynamic exit exit ""
+//go:cgo_import_dynamic fstat$INODE64 fstat$INODE64 ""
+//go:cgo_import_dynamic ftruncate ftruncate ""
+//go:cgo_import_dynamic getpid getpid ""
+//go:cgo_import_dynamic getrlimit getrlimit ""
+//go:cgo_import_dynamic gettimeofday gettimeofday ""
+//go:cgo_import_dynamic getuid getuid ""
+//go:cgo_import_dynamic grantpt grantpt ""
+//go:cgo_import_dynamic ioctl ioctl ""
+//go:cgo_import_dynamic isatty isatty ""
+//go:cgo_import_dynamic lstat$INODE64 lstat$INODE64 ""
+//go:cgo_import_dynamic mach_absolute_time mach_absolute_time ""
+//go:cgo_import_dynamic mach_task_self_ mach_task_self_ ""
+//go:cgo_import_dynamic mach_timebase_info mach_timebase_info ""
+//go:cgo_import_dynamic mach_vm_region_recurse mach_vm_region_recurse ""
+//go:cgo_import_dynamic madvise madvise ""
+//go:cgo_import_dynamic malloc_num_zones malloc_num_zones ""
+//go:cgo_import_dynamic malloc_zones malloc_zones ""
+//go:cgo_import_dynamic memcpy memcpy ""
+//go:cgo_import_dynamic memset_pattern16 memset_pattern16 ""
+//go:cgo_import_dynamic mkdir mkdir ""
+//go:cgo_import_dynamic mprotect mprotect ""
+//go:cgo_import_dynamic open open ""
+//go:cgo_import_dynamic pipe pipe ""
+//go:cgo_import_dynamic posix_openpt posix_openpt ""
+//go:cgo_import_dynamic posix_spawn posix_spawn ""
+//go:cgo_import_dynamic posix_spawn_file_actions_addclose posix_spawn_file_actions_addclose ""
+//go:cgo_import_dynamic posix_spawn_file_actions_adddup2 posix_spawn_file_actions_adddup2 ""
+//go:cgo_import_dynamic posix_spawn_file_actions_destroy posix_spawn_file_actions_destroy ""
+//go:cgo_import_dynamic posix_spawn_file_actions_init posix_spawn_file_actions_init ""
+//go:cgo_import_dynamic posix_spawnattr_destroy posix_spawnattr_destroy ""
+//go:cgo_import_dynamic posix_spawnattr_init posix_spawnattr_init ""
+//go:cgo_import_dynamic posix_spawnattr_setflags posix_spawnattr_setflags ""
+//go:cgo_import_dynamic pthread_attr_getstack pthread_attr_getstack ""
+//go:cgo_import_dynamic pthread_create pthread_create ""
+//go:cgo_import_dynamic pthread_get_stackaddr_np pthread_get_stackaddr_np ""
+//go:cgo_import_dynamic pthread_get_stacksize_np pthread_get_stacksize_np ""
+//go:cgo_import_dynamic pthread_getspecific pthread_getspecific ""
+//go:cgo_import_dynamic pthread_introspection_hook_install pthread_introspection_hook_install ""
+//go:cgo_import_dynamic pthread_join pthread_join ""
+//go:cgo_import_dynamic pthread_self pthread_self ""
+//go:cgo_import_dynamic pthread_sigmask pthread_sigmask ""
+//go:cgo_import_dynamic pthread_threadid_np pthread_threadid_np ""
+//go:cgo_import_dynamic read read ""
+//go:cgo_import_dynamic readlink readlink ""
+//go:cgo_import_dynamic realpath$DARWIN_EXTSN realpath$DARWIN_EXTSN ""
+//go:cgo_import_dynamic rename rename ""
+//go:cgo_import_dynamic sched_yield sched_yield ""
+//go:cgo_import_dynamic setrlimit setrlimit ""
+//go:cgo_import_dynamic sigaction sigaction ""
+//go:cgo_import_dynamic stat$INODE64 stat$INODE64 ""
+//go:cgo_import_dynamic sysconf sysconf ""
+//go:cgo_import_dynamic sysctl sysctl ""
+//go:cgo_import_dynamic sysctlbyname sysctlbyname ""
+//go:cgo_import_dynamic task_info task_info ""
+//go:cgo_import_dynamic tcgetattr tcgetattr ""
+//go:cgo_import_dynamic tcsetattr tcsetattr ""
+//go:cgo_import_dynamic unlink unlink ""
+//go:cgo_import_dynamic unlockpt unlockpt ""
+//go:cgo_import_dynamic usleep usleep ""
+//go:cgo_import_dynamic vm_region_64 vm_region_64 ""
+//go:cgo_import_dynamic vm_region_recurse_64 vm_region_recurse_64 ""
+//go:cgo_import_dynamic waitpid waitpid ""
+//go:cgo_import_dynamic write write ""
+//go:cgo_import_dynamic memcpy memcpy ""
+//go:cgo_import_dynamic memmove memmove ""
+//go:cgo_import_dynamic memset memset ""

src/runtime/race/race_darwin_arm64.go

@@ -0,0 +1,108 @@
+// Copyright 2022 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.
+
+// Code generated by mkcgo.sh. DO NOT EDIT.
+
+//go:build race
+
+package race
+
+//go:cgo_import_dynamic _Block_object_assign _Block_object_assign ""
+//go:cgo_import_dynamic _Block_object_dispose _Block_object_dispose ""
+//go:cgo_import_dynamic _NSConcreteStackBlock _NSConcreteStackBlock ""
+//go:cgo_import_dynamic _NSGetArgv _NSGetArgv ""
+//go:cgo_import_dynamic _NSGetEnviron _NSGetEnviron ""
+//go:cgo_import_dynamic _NSGetExecutablePath _NSGetExecutablePath ""
+//go:cgo_import_dynamic __error __error ""
+//go:cgo_import_dynamic __fork __fork ""
+//go:cgo_import_dynamic __mmap __mmap ""
+//go:cgo_import_dynamic __munmap __munmap ""
+//go:cgo_import_dynamic __stack_chk_fail __stack_chk_fail ""
+//go:cgo_import_dynamic __stack_chk_guard __stack_chk_guard ""
+//go:cgo_import_dynamic _dyld_get_image_header _dyld_get_image_header ""
+//go:cgo_import_dynamic _dyld_get_image_name _dyld_get_image_name ""
+//go:cgo_import_dynamic _dyld_get_image_vmaddr_slide _dyld_get_image_vmaddr_slide ""
+//go:cgo_import_dynamic _dyld_get_shared_cache_range _dyld_get_shared_cache_range ""
+//go:cgo_import_dynamic _dyld_get_shared_cache_uuid _dyld_get_shared_cache_uuid ""
+//go:cgo_import_dynamic _dyld_image_count _dyld_image_count ""
+//go:cgo_import_dynamic _exit _exit ""
+//go:cgo_import_dynamic _sanitizer_internal_memcpy _sanitizer_internal_memcpy ""
+//go:cgo_import_dynamic _sanitizer_internal_memmove _sanitizer_internal_memmove ""
+//go:cgo_import_dynamic _sanitizer_internal_memset _sanitizer_internal_memset ""
+//go:cgo_import_dynamic abort abort ""
+//go:cgo_import_dynamic arc4random_buf arc4random_buf ""
+//go:cgo_import_dynamic bzero bzero ""
+//go:cgo_import_dynamic close close ""
+//go:cgo_import_dynamic dlsym dlsym ""
+//go:cgo_import_dynamic dup dup ""
+//go:cgo_import_dynamic dup2 dup2 ""
+//go:cgo_import_dynamic dyld_shared_cache_iterate_text dyld_shared_cache_iterate_text ""
+//go:cgo_import_dynamic execve execve ""
+//go:cgo_import_dynamic exit exit ""
+//go:cgo_import_dynamic fstat fstat ""
+//go:cgo_import_dynamic ftruncate ftruncate ""
+//go:cgo_import_dynamic getpid getpid ""
+//go:cgo_import_dynamic getrlimit getrlimit ""
+//go:cgo_import_dynamic gettimeofday gettimeofday ""
+//go:cgo_import_dynamic getuid getuid ""
+//go:cgo_import_dynamic grantpt grantpt ""
+//go:cgo_import_dynamic ioctl ioctl ""
+//go:cgo_import_dynamic isatty isatty ""
+//go:cgo_import_dynamic lstat lstat ""
+//go:cgo_import_dynamic mach_absolute_time mach_absolute_time ""
+//go:cgo_import_dynamic mach_task_self_ mach_task_self_ ""
+//go:cgo_import_dynamic mach_timebase_info mach_timebase_info ""
+//go:cgo_import_dynamic mach_vm_region_recurse mach_vm_region_recurse ""
+//go:cgo_import_dynamic madvise madvise ""
+//go:cgo_import_dynamic malloc_num_zones malloc_num_zones ""
+//go:cgo_import_dynamic malloc_zones malloc_zones ""
+//go:cgo_import_dynamic memcpy memcpy ""
+//go:cgo_import_dynamic memset_pattern16 memset_pattern16 ""
+//go:cgo_import_dynamic mkdir mkdir ""
+//go:cgo_import_dynamic mprotect mprotect ""
+//go:cgo_import_dynamic open open ""
+//go:cgo_import_dynamic pipe pipe ""
+//go:cgo_import_dynamic posix_openpt posix_openpt ""
+//go:cgo_import_dynamic posix_spawn posix_spawn ""
+//go:cgo_import_dynamic posix_spawn_file_actions_addclose posix_spawn_file_actions_addclose ""
+//go:cgo_import_dynamic posix_spawn_file_actions_adddup2 posix_spawn_file_actions_adddup2 ""
+//go:cgo_import_dynamic posix_spawn_file_actions_destroy posix_spawn_file_actions_destroy ""
+//go:cgo_import_dynamic posix_spawn_file_actions_init posix_spawn_file_actions_init ""
+//go:cgo_import_dynamic posix_spawnattr_destroy posix_spawnattr_destroy ""
+//go:cgo_import_dynamic posix_spawnattr_init posix_spawnattr_init ""
+//go:cgo_import_dynamic posix_spawnattr_setflags posix_spawnattr_setflags ""
+//go:cgo_import_dynamic pthread_attr_getstack pthread_attr_getstack ""
+//go:cgo_import_dynamic pthread_create pthread_create ""
+//go:cgo_import_dynamic pthread_get_stackaddr_np pthread_get_stackaddr_np ""
+//go:cgo_import_dynamic pthread_get_stacksize_np pthread_get_stacksize_np ""
+//go:cgo_import_dynamic pthread_getspecific pthread_getspecific ""
+//go:cgo_import_dynamic pthread_introspection_hook_install pthread_introspection_hook_install ""
+//go:cgo_import_dynamic pthread_join pthread_join ""
+//go:cgo_import_dynamic pthread_self pthread_self ""
+//go:cgo_import_dynamic pthread_sigmask pthread_sigmask ""
+//go:cgo_import_dynamic pthread_threadid_np pthread_threadid_np ""
+//go:cgo_import_dynamic read read ""
+//go:cgo_import_dynamic readlink readlink ""
+//go:cgo_import_dynamic realpath$DARWIN_EXTSN realpath$DARWIN_EXTSN ""
+//go:cgo_import_dynamic rename rename ""
+//go:cgo_import_dynamic sched_yield sched_yield ""
+//go:cgo_import_dynamic setrlimit setrlimit ""
+//go:cgo_import_dynamic sigaction sigaction ""
+//go:cgo_import_dynamic stat stat ""
+//go:cgo_import_dynamic sysconf sysconf ""
+//go:cgo_import_dynamic sysctl sysctl ""
+//go:cgo_import_dynamic sysctlbyname sysctlbyname ""
+//go:cgo_import_dynamic task_info task_info ""
+//go:cgo_import_dynamic tcgetattr tcgetattr ""
+//go:cgo_import_dynamic tcsetattr tcsetattr ""
+//go:cgo_import_dynamic unlink unlink ""
+//go:cgo_import_dynamic unlockpt unlockpt ""
+//go:cgo_import_dynamic usleep usleep ""
+//go:cgo_import_dynamic vm_region_64 vm_region_64 ""
+//go:cgo_import_dynamic vm_region_recurse_64 vm_region_recurse_64 ""
+//go:cgo_import_dynamic waitpid waitpid ""
+//go:cgo_import_dynamic write write ""
+//go:cgo_import_dynamic memcpy memcpy ""
+//go:cgo_import_dynamic memmove memmove ""
+//go:cgo_import_dynamic memset memset ""

src/runtime/race/race_linux_test.go

@@ -0,0 +1,65 @@
+// Copyright 2016 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.
+
+//go:build linux && race
+
+package race_test
+
+import (
+	"sync/atomic"
+	"syscall"
+	"testing"
+	"unsafe"
+)
+
+func TestAtomicMmap(t *testing.T) {
+	// Test that atomic operations work on "external" memory. Previously they crashed (#16206).
+	// Also do a sanity correctness check: under race detector atomic operations
+	// are implemented inside of race runtime.
+	mem, err := syscall.Mmap(-1, 0, 1<<20, syscall.PROT_READ|syscall.PROT_WRITE, syscall.MAP_ANON|syscall.MAP_PRIVATE)
+	if err != nil {
+		t.Fatalf("mmap failed: %v", err)
+	}
+	defer syscall.Munmap(mem)
+	a := (*uint64)(unsafe.Pointer(&mem[0]))
+	if *a != 0 {
+		t.Fatalf("bad atomic value: %v, want 0", *a)
+	}
+	atomic.AddUint64(a, 1)
+	if *a != 1 {
+		t.Fatalf("bad atomic value: %v, want 1", *a)
+	}
+	atomic.AddUint64(a, 1)
+	if *a != 2 {
+		t.Fatalf("bad atomic value: %v, want 2", *a)
+	}
+}
+
+func TestAtomicPageBoundary(t *testing.T) {
+	// Test that atomic access near (but not cross) a page boundary
+	// doesn't fault. See issue 60825.
+
+	// Mmap two pages of memory, and make the second page inaccessible,
+	// so we have an address at the end of a page.
+	pagesize := syscall.Getpagesize()
+	b, err := syscall.Mmap(0, 0, 2*pagesize, syscall.PROT_READ|syscall.PROT_WRITE, syscall.MAP_ANON|syscall.MAP_PRIVATE)
+	if err != nil {
+		t.Fatalf("mmap failed %s", err)
+	}
+	defer syscall.Munmap(b)
+	err = syscall.Mprotect(b[pagesize:], syscall.PROT_NONE)
+	if err != nil {
+		t.Fatalf("mprotect high failed %s\n", err)
+	}
+
+	// This should not fault.
+	a := (*uint32)(unsafe.Pointer(&b[pagesize-4]))
+	atomic.StoreUint32(a, 1)
+	if x := atomic.LoadUint32(a); x != 1 {
+		t.Fatalf("bad atomic value: %v, want 1", x)
+	}
+	if x := atomic.AddUint32(a, 1); x != 2 {
+		t.Fatalf("bad atomic value: %v, want 2", x)
+	}
+}

src/runtime/race/race_test.go

@@ -0,0 +1,250 @@
+// Copyright 2012 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.
+
+//go:build race
+
+// This program is used to verify the race detector
+// by running the tests and parsing their output.
+// It does not check stack correctness, completeness or anything else:
+// it merely verifies that if a test is expected to be racy
+// then the race is detected.
+package race_test
+
+import (
+	"bufio"
+	"bytes"
+	"fmt"
+	"internal/testenv"
+	"io"
+	"log"
+	"math/rand"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"strings"
+	"sync"
+	"sync/atomic"
+	"testing"
+)
+
+var (
+	passedTests = 0
+	totalTests  = 0
+	falsePos    = 0
+	falseNeg    = 0
+	failingPos  = 0
+	failingNeg  = 0
+	failed      = false
+)
+
+const (
+	visibleLen = 40
+	testPrefix = "=== RUN   Test"
+)
+
+func TestRace(t *testing.T) {
+	testOutput, err := runTests(t)
+	if err != nil {
+		t.Fatalf("Failed to run tests: %v\n%v", err, string(testOutput))
+	}
+	reader := bufio.NewReader(bytes.NewReader(testOutput))
+
+	funcName := ""
+	var tsanLog []string
+	for {
+		s, err := nextLine(reader)
+		if err != nil {
+			fmt.Printf("%s\n", processLog(funcName, tsanLog))
+			break
+		}
+		if strings.HasPrefix(s, testPrefix) {
+			fmt.Printf("%s\n", processLog(funcName, tsanLog))
+			tsanLog = make([]string, 0, 100)
+			funcName = s[len(testPrefix):]
+		} else {
+			tsanLog = append(tsanLog, s)
+		}
+	}
+
+	if totalTests == 0 {
+		t.Fatalf("failed to parse test output:\n%s", testOutput)
+	}
+	fmt.Printf("\nPassed %d of %d tests (%.02f%%, %d+, %d-)\n",
+		passedTests, totalTests, 100*float64(passedTests)/float64(totalTests), falsePos, falseNeg)
+	fmt.Printf("%d expected failures (%d has not fail)\n", failingPos+failingNeg, failingNeg)
+	if failed {
+		t.Fail()
+	}
+}
+
+// nextLine is a wrapper around bufio.Reader.ReadString.
+// It reads a line up to the next '\n' character. Error
+// is non-nil if there are no lines left, and nil
+// otherwise.
+func nextLine(r *bufio.Reader) (string, error) {
+	s, err := r.ReadString('\n')
+	if err != nil {
+		if err != io.EOF {
+			log.Fatalf("nextLine: expected EOF, received %v", err)
+		}
+		return s, err
+	}
+	return s[:len(s)-1], nil
+}
+
+// processLog verifies whether the given ThreadSanitizer's log
+// contains a race report, checks this information against
+// the name of the testcase and returns the result of this
+// comparison.
+func processLog(testName string, tsanLog []string) string {
+	if !strings.HasPrefix(testName, "Race") && !strings.HasPrefix(testName, "NoRace") {
+		return ""
+	}
+	gotRace := false
+	for _, s := range tsanLog {
+		if strings.Contains(s, "DATA RACE") {
+			gotRace = true
+			break
+		}
+	}
+
+	failing := strings.Contains(testName, "Failing")
+	expRace := !strings.HasPrefix(testName, "No")
+	for len(testName) < visibleLen {
+		testName += " "
+	}
+	if expRace == gotRace {
+		passedTests++
+		totalTests++
+		if failing {
+			failed = true
+			failingNeg++
+		}
+		return fmt.Sprintf("%s .", testName)
+	}
+	pos := ""
+	if expRace {
+		falseNeg++
+	} else {
+		falsePos++
+		pos = "+"
+	}
+	if failing {
+		failingPos++
+	} else {
+		failed = true
+	}
+	totalTests++
+	return fmt.Sprintf("%s %s%s", testName, "FAILED", pos)
+}
+
+// runTests assures that the package and its dependencies is
+// built with instrumentation enabled and returns the output of 'go test'
+// which includes possible data race reports from ThreadSanitizer.
+func runTests(t *testing.T) ([]byte, error) {
+	tests, err := filepath.Glob("./testdata/*_test.go")
+	if err != nil {
+		return nil, err
+	}
+	args := []string{"test", "-race", "-v"}
+	args = append(args, tests...)
+	cmd := exec.Command(testenv.GoToolPath(t), args...)
+	// The following flags turn off heuristics that suppress seemingly identical reports.
+	// It is required because the tests contain a lot of data races on the same addresses
+	// (the tests are simple and the memory is constantly reused).
+	for _, env := range os.Environ() {
+		if strings.HasPrefix(env, "GOMAXPROCS=") ||
+			strings.HasPrefix(env, "GODEBUG=") ||
+			strings.HasPrefix(env, "GORACE=") {
+			continue
+		}
+		cmd.Env = append(cmd.Env, env)
+	}
+	// We set GOMAXPROCS=1 to prevent test flakiness.
+	// There are two sources of flakiness:
+	// 1. Some tests rely on particular execution order.
+	//    If the order is different, race does not happen at all.
+	// 2. Ironically, ThreadSanitizer runtime contains a logical race condition
+	//    that can lead to false negatives if racy accesses happen literally at the same time.
+	// Tests used to work reliably in the good old days of GOMAXPROCS=1.
+	// So let's set it for now. A more reliable solution is to explicitly annotate tests
+	// with required execution order by means of a special "invisible" synchronization primitive
+	// (that's what is done for C++ ThreadSanitizer tests). This is issue #14119.
+	cmd.Env = append(cmd.Env,
+		"GOMAXPROCS=1",
+		"GORACE=suppress_equal_stacks=0 suppress_equal_addresses=0",
+	)
+	// There are races: we expect tests to fail and the exit code to be non-zero.
+	out, _ := cmd.CombinedOutput()
+	if bytes.Contains(out, []byte("fatal error:")) {
+		// But don't expect runtime to crash.
+		return out, fmt.Errorf("runtime fatal error")
+	}
+	return out, nil
+}
+
+func TestIssue8102(t *testing.T) {
+	// If this compiles with -race, the test passes.
+	type S struct {
+		x any
+		i int
+	}
+	c := make(chan int)
+	a := [2]*int{}
+	for ; ; c <- *a[S{}.i] {
+		if t != nil {
+			break
+		}
+	}
+}
+
+func TestIssue9137(t *testing.T) {
+	a := []string{"a"}
+	i := 0
+	a[i], a[len(a)-1], a = a[len(a)-1], "", a[:len(a)-1]
+	if len(a) != 0 || a[:1][0] != "" {
+		t.Errorf("mangled a: %q %q", a, a[:1])
+	}
+}
+
+func BenchmarkSyncLeak(b *testing.B) {
+	const (
+		G = 1000
+		S = 1000
+		H = 10
+	)
+	var wg sync.WaitGroup
+	wg.Add(G)
+	for g := 0; g < G; g++ {
+		go func() {
+			defer wg.Done()
+			hold := make([][]uint32, H)
+			for i := 0; i < b.N; i++ {
+				a := make([]uint32, S)
+				atomic.AddUint32(&a[rand.Intn(len(a))], 1)
+				hold[rand.Intn(len(hold))] = a
+			}
+			_ = hold
+		}()
+	}
+	wg.Wait()
+}
+
+func BenchmarkStackLeak(b *testing.B) {
+	done := make(chan bool, 1)
+	for i := 0; i < b.N; i++ {
+		go func() {
+			growStack(rand.Intn(100))
+			done <- true
+		}()
+		<-done
+	}
+}
+
+func growStack(i int) {
+	if i == 0 {
+		return
+	}
+	growStack(i - 1)
+}

src/runtime/race/race_unix_test.go

@@ -0,0 +1,29 @@
+// Copyright 2014 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.
+
+//go:build race && (darwin || freebsd || linux)
+
+package race_test
+
+import (
+	"sync/atomic"
+	"syscall"
+	"testing"
+	"unsafe"
+)
+
+// Test that race detector does not crash when accessing non-Go allocated memory (issue 9136).
+func TestNonGoMemory(t *testing.T) {
+	data, err := syscall.Mmap(-1, 0, 4096, syscall.PROT_READ|syscall.PROT_WRITE, syscall.MAP_ANON|syscall.MAP_PRIVATE)
+	if err != nil {
+		t.Fatalf("failed to mmap memory: %v", err)
+	}
+	defer syscall.Munmap(data)
+	p := (*uint32)(unsafe.Pointer(&data[0]))
+	atomic.AddUint32(p, 1)
+	(*p)++
+	if *p != 2 {
+		t.Fatalf("data[0] = %v, expect 2", *p)
+	}
+}

src/runtime/race/race_v1_amd64.go

@@ -0,0 +1,9 @@
+// Copyright 2022 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.
+
+//go:build (linux && !amd64.v3) || darwin || freebsd || netbsd || openbsd || windows
+
+package race
+
+import _ "runtime/race/internal/amd64v1"

src/runtime/race/race_v3_amd64.go

@@ -0,0 +1,9 @@
+// Copyright 2022 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.
+
+//go:build linux && amd64.v3
+
+package race
+
+import _ "runtime/race/internal/amd64v3"

src/runtime/race/race_windows_test.go

@@ -0,0 +1,46 @@
+// Copyright 2016 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.
+
+//go:build windows && race
+
+package race_test
+
+import (
+	"sync/atomic"
+	"syscall"
+	"testing"
+	"unsafe"
+)
+
+func TestAtomicMmap(t *testing.T) {
+	// Test that atomic operations work on "external" memory. Previously they crashed (#16206).
+	// Also do a sanity correctness check: under race detector atomic operations
+	// are implemented inside of race runtime.
+	kernel32 := syscall.NewLazyDLL("kernel32.dll")
+	VirtualAlloc := kernel32.NewProc("VirtualAlloc")
+	VirtualFree := kernel32.NewProc("VirtualFree")
+	const (
+		MEM_COMMIT     = 0x00001000
+		MEM_RESERVE    = 0x00002000
+		MEM_RELEASE    = 0x8000
+		PAGE_READWRITE = 0x04
+	)
+	mem, _, err := syscall.Syscall6(VirtualAlloc.Addr(), 4, 0, 1<<20, MEM_COMMIT|MEM_RESERVE, PAGE_READWRITE, 0, 0)
+	if err != 0 {
+		t.Fatalf("VirtualAlloc failed: %v", err)
+	}
+	defer syscall.Syscall(VirtualFree.Addr(), 3, mem, 1<<20, MEM_RELEASE)
+	a := (*uint64)(unsafe.Pointer(mem))
+	if *a != 0 {
+		t.Fatalf("bad atomic value: %v, want 0", *a)
+	}
+	atomic.AddUint64(a, 1)
+	if *a != 1 {
+		t.Fatalf("bad atomic value: %v, want 1", *a)
+	}
+	atomic.AddUint64(a, 1)
+	if *a != 2 {
+		t.Fatalf("bad atomic value: %v, want 2", *a)
+	}
+}

src/runtime/race/sched_test.go

@@ -0,0 +1,48 @@
+// Copyright 2015 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.
+
+//go:build race
+
+package race_test
+
+import (
+	"fmt"
+	"reflect"
+	"runtime"
+	"strings"
+	"testing"
+)
+
+func TestRandomScheduling(t *testing.T) {
+	// Scheduler is most consistent with GOMAXPROCS=1.
+	// Use that to make the test most likely to fail.
+	defer runtime.GOMAXPROCS(runtime.GOMAXPROCS(1))
+	const N = 10
+	out := make([][]int, N)
+	for i := 0; i < N; i++ {
+		c := make(chan int, N)
+		for j := 0; j < N; j++ {
+			go func(j int) {
+				c <- j
+			}(j)
+		}
+		row := make([]int, N)
+		for j := 0; j < N; j++ {
+			row[j] = <-c
+		}
+		out[i] = row
+	}
+
+	for i := 0; i < N; i++ {
+		if !reflect.DeepEqual(out[0], out[i]) {
+			return // found a different order
+		}
+	}
+
+	var buf strings.Builder
+	for i := 0; i < N; i++ {
+		fmt.Fprintf(&buf, "%v\n", out[i])
+	}
+	t.Fatalf("consistent goroutine execution order:\n%v", buf.String())
+}

src/runtime/race/syso_test.go

@@ -0,0 +1,33 @@
+// Copyright 2020 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.
+
+//go:build race
+
+package race
+
+import (
+	"bytes"
+	"os/exec"
+	"path/filepath"
+	"runtime"
+	"testing"
+)
+
+func TestIssue37485(t *testing.T) {
+	files, err := filepath.Glob("./*.syso")
+	if err != nil {
+		t.Fatalf("can't find syso files: %s", err)
+	}
+	for _, f := range files {
+		cmd := exec.Command(filepath.Join(runtime.GOROOT(), "bin", "go"), "tool", "nm", f)
+		res, err := cmd.CombinedOutput()
+		if err != nil {
+			t.Errorf("nm of %s failed: %s", f, err)
+			continue
+		}
+		if bytes.Contains(res, []byte("getauxval")) {
+			t.Errorf("%s contains getauxval", f)
+		}
+	}
+}

src/runtime/race/testdata/atomic_test.go

@@ -0,0 +1,325 @@
+// Copyright 2011 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 race_test
+
+import (
+	"runtime"
+	"sync"
+	"sync/atomic"
+	"testing"
+	"unsafe"
+)
+
+func TestNoRaceAtomicAddInt64(t *testing.T) {
+	var x1, x2 int8
+	_ = x1 + x2
+	var s int64
+	ch := make(chan bool, 2)
+	go func() {
+		x1 = 1
+		if atomic.AddInt64(&s, 1) == 2 {
+			x2 = 1
+		}
+		ch <- true
+	}()
+	go func() {
+		x2 = 1
+		if atomic.AddInt64(&s, 1) == 2 {
+			x1 = 1
+		}
+		ch <- true
+	}()
+	<-ch
+	<-ch
+}
+
+func TestRaceAtomicAddInt64(t *testing.T) {
+	var x1, x2 int8
+	_ = x1 + x2
+	var s int64
+	ch := make(chan bool, 2)
+	go func() {
+		x1 = 1
+		if atomic.AddInt64(&s, 1) == 1 {
+			x2 = 1
+		}
+		ch <- true
+	}()
+	go func() {
+		x2 = 1
+		if atomic.AddInt64(&s, 1) == 1 {
+			x1 = 1
+		}
+		ch <- true
+	}()
+	<-ch
+	<-ch
+}
+
+func TestNoRaceAtomicAddInt32(t *testing.T) {
+	var x1, x2 int8
+	_ = x1 + x2
+	var s int32
+	ch := make(chan bool, 2)
+	go func() {
+		x1 = 1
+		if atomic.AddInt32(&s, 1) == 2 {
+			x2 = 1
+		}
+		ch <- true
+	}()
+	go func() {
+		x2 = 1
+		if atomic.AddInt32(&s, 1) == 2 {
+			x1 = 1
+		}
+		ch <- true
+	}()
+	<-ch
+	<-ch
+}
+
+func TestNoRaceAtomicLoadAddInt32(t *testing.T) {
+	var x int64
+	_ = x
+	var s int32
+	go func() {
+		x = 2
+		atomic.AddInt32(&s, 1)
+	}()
+	for atomic.LoadInt32(&s) != 1 {
+		runtime.Gosched()
+	}
+	x = 1
+}
+
+func TestNoRaceAtomicLoadStoreInt32(t *testing.T) {
+	var x int64
+	_ = x
+	var s int32
+	go func() {
+		x = 2
+		atomic.StoreInt32(&s, 1)
+	}()
+	for atomic.LoadInt32(&s) != 1 {
+		runtime.Gosched()
+	}
+	x = 1
+}
+
+func TestNoRaceAtomicStoreCASInt32(t *testing.T) {
+	var x int64
+	_ = x
+	var s int32
+	go func() {
+		x = 2
+		atomic.StoreInt32(&s, 1)
+	}()
+	for !atomic.CompareAndSwapInt32(&s, 1, 0) {
+		runtime.Gosched()
+	}
+	x = 1
+}
+
+func TestNoRaceAtomicCASLoadInt32(t *testing.T) {
+	var x int64
+	_ = x
+	var s int32
+	go func() {
+		x = 2
+		if !atomic.CompareAndSwapInt32(&s, 0, 1) {
+			panic("")
+		}
+	}()
+	for atomic.LoadInt32(&s) != 1 {
+		runtime.Gosched()
+	}
+	x = 1
+}
+
+func TestNoRaceAtomicCASCASInt32(t *testing.T) {
+	var x int64
+	_ = x
+	var s int32
+	go func() {
+		x = 2
+		if !atomic.CompareAndSwapInt32(&s, 0, 1) {
+			panic("")
+		}
+	}()
+	for !atomic.CompareAndSwapInt32(&s, 1, 0) {
+		runtime.Gosched()
+	}
+	x = 1
+}
+
+func TestNoRaceAtomicCASCASInt32_2(t *testing.T) {
+	var x1, x2 int8
+	_ = x1 + x2
+	var s int32
+	ch := make(chan bool, 2)
+	go func() {
+		x1 = 1
+		if !atomic.CompareAndSwapInt32(&s, 0, 1) {
+			x2 = 1
+		}
+		ch <- true
+	}()
+	go func() {
+		x2 = 1
+		if !atomic.CompareAndSwapInt32(&s, 0, 1) {
+			x1 = 1
+		}
+		ch <- true
+	}()
+	<-ch
+	<-ch
+}
+
+func TestNoRaceAtomicLoadInt64(t *testing.T) {
+	var x int32
+	_ = x
+	var s int64
+	go func() {
+		x = 2
+		atomic.AddInt64(&s, 1)
+	}()
+	for atomic.LoadInt64(&s) != 1 {
+		runtime.Gosched()
+	}
+	x = 1
+}
+
+func TestNoRaceAtomicCASCASUInt64(t *testing.T) {
+	var x int64
+	_ = x
+	var s uint64
+	go func() {
+		x = 2
+		if !atomic.CompareAndSwapUint64(&s, 0, 1) {
+			panic("")
+		}
+	}()
+	for !atomic.CompareAndSwapUint64(&s, 1, 0) {
+		runtime.Gosched()
+	}
+	x = 1
+}
+
+func TestNoRaceAtomicLoadStorePointer(t *testing.T) {
+	var x int64
+	_ = x
+	var s unsafe.Pointer
+	var y int = 2
+	var p unsafe.Pointer = unsafe.Pointer(&y)
+	go func() {
+		x = 2
+		atomic.StorePointer(&s, p)
+	}()
+	for atomic.LoadPointer(&s) != p {
+		runtime.Gosched()
+	}
+	x = 1
+}
+
+func TestNoRaceAtomicStoreCASUint64(t *testing.T) {
+	var x int64
+	_ = x
+	var s uint64
+	go func() {
+		x = 2
+		atomic.StoreUint64(&s, 1)
+	}()
+	for !atomic.CompareAndSwapUint64(&s, 1, 0) {
+		runtime.Gosched()
+	}
+	x = 1
+}
+
+func TestRaceAtomicStoreLoad(t *testing.T) {
+	c := make(chan bool)
+	var a uint64
+	go func() {
+		atomic.StoreUint64(&a, 1)
+		c <- true
+	}()
+	_ = a
+	<-c
+}
+
+func TestRaceAtomicLoadStore(t *testing.T) {
+	c := make(chan bool)
+	var a uint64
+	go func() {
+		_ = atomic.LoadUint64(&a)
+		c <- true
+	}()
+	a = 1
+	<-c
+}
+
+func TestRaceAtomicAddLoad(t *testing.T) {
+	c := make(chan bool)
+	var a uint64
+	go func() {
+		atomic.AddUint64(&a, 1)
+		c <- true
+	}()
+	_ = a
+	<-c
+}
+
+func TestRaceAtomicAddStore(t *testing.T) {
+	c := make(chan bool)
+	var a uint64
+	go func() {
+		atomic.AddUint64(&a, 1)
+		c <- true
+	}()
+	a = 42
+	<-c
+}
+
+// A nil pointer in an atomic operation should not deadlock
+// the rest of the program. Used to hang indefinitely.
+func TestNoRaceAtomicCrash(t *testing.T) {
+	var mutex sync.Mutex
+	var nilptr *int32
+	panics := 0
+	defer func() {
+		if x := recover(); x != nil {
+			mutex.Lock()
+			panics++
+			mutex.Unlock()
+		} else {
+			panic("no panic")
+		}
+	}()
+	atomic.AddInt32(nilptr, 1)
+}
+
+func TestNoRaceDeferAtomicStore(t *testing.T) {
+	// Test that when an atomic function is deferred directly, the
+	// GC scans it correctly. See issue 42599.
+	type foo struct {
+		bar int64
+	}
+
+	var doFork func(f *foo, depth int)
+	doFork = func(f *foo, depth int) {
+		atomic.StoreInt64(&f.bar, 1)
+		defer atomic.StoreInt64(&f.bar, 0)
+		if depth > 0 {
+			for i := 0; i < 2; i++ {
+				f2 := &foo{}
+				go doFork(f2, depth-1)
+			}
+		}
+		runtime.GC()
+	}
+
+	f := &foo{}
+	doFork(f, 11)
+}

src/runtime/race/testdata/cgo_test.go

@@ -0,0 +1,21 @@
+// Copyright 2012 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 race_test
+
+import (
+	"internal/testenv"
+	"os"
+	"os/exec"
+	"testing"
+)
+
+func TestNoRaceCgoSync(t *testing.T) {
+	cmd := exec.Command(testenv.GoToolPath(t), "run", "-race", "cgo_test_main.go")
+	cmd.Stdout = os.Stdout
+	cmd.Stderr = os.Stderr
+	if err := cmd.Run(); err != nil {
+		t.Fatalf("program exited with error: %v\n", err)
+	}
+}

src/runtime/race/testdata/cgo_test_main.go

@@ -0,0 +1,30 @@
+// Copyright 2012 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
+
+/*
+int sync;
+
+void Notify(void)
+{
+	__sync_fetch_and_add(&sync, 1);
+}
+
+void Wait(void)
+{
+	while(__sync_fetch_and_add(&sync, 0) == 0) {}
+}
+*/
+import "C"
+
+func main() {
+	data := 0
+	go func() {
+		data = 1
+		C.Notify()
+	}()
+	C.Wait()
+	_ = data
+}

src/runtime/race/testdata/chan_test.go

@@ -0,0 +1,787 @@
+// Copyright 2011 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 race_test
+
+import (
+	"runtime"
+	"testing"
+	"time"
+)
+
+func TestNoRaceChanSync(t *testing.T) {
+	v := 0
+	_ = v
+	c := make(chan int)
+	go func() {
+		v = 1
+		c <- 0
+	}()
+	<-c
+	v = 2
+}
+
+func TestNoRaceChanSyncRev(t *testing.T) {
+	v := 0
+	_ = v
+	c := make(chan int)
+	go func() {
+		c <- 0
+		v = 2
+	}()
+	v = 1
+	<-c
+}
+
+func TestNoRaceChanAsync(t *testing.T) {
+	v := 0
+	_ = v
+	c := make(chan int, 10)
+	go func() {
+		v = 1
+		c <- 0
+	}()
+	<-c
+	v = 2
+}
+
+func TestRaceChanAsyncRev(t *testing.T) {
+	v := 0
+	_ = v
+	c := make(chan int, 10)
+	go func() {
+		c <- 0
+		v = 1
+	}()
+	v = 2
+	<-c
+}
+
+func TestNoRaceChanAsyncCloseRecv(t *testing.T) {
+	v := 0
+	_ = v
+	c := make(chan int, 10)
+	go func() {
+		v = 1
+		close(c)
+	}()
+	func() {
+		defer func() {
+			recover()
+			v = 2
+		}()
+		<-c
+	}()
+}
+
+func TestNoRaceChanAsyncCloseRecv2(t *testing.T) {
+	v := 0
+	_ = v
+	c := make(chan int, 10)
+	go func() {
+		v = 1
+		close(c)
+	}()
+	_, _ = <-c
+	v = 2
+}
+
+func TestNoRaceChanAsyncCloseRecv3(t *testing.T) {
+	v := 0
+	_ = v
+	c := make(chan int, 10)
+	go func() {
+		v = 1
+		close(c)
+	}()
+	for range c {
+	}
+	v = 2
+}
+
+func TestNoRaceChanSyncCloseRecv(t *testing.T) {
+	v := 0
+	_ = v
+	c := make(chan int)
+	go func() {
+		v = 1
+		close(c)
+	}()
+	func() {
+		defer func() {
+			recover()
+			v = 2
+		}()
+		<-c
+	}()
+}
+
+func TestNoRaceChanSyncCloseRecv2(t *testing.T) {
+	v := 0
+	_ = v
+	c := make(chan int)
+	go func() {
+		v = 1
+		close(c)
+	}()
+	_, _ = <-c
+	v = 2
+}
+
+func TestNoRaceChanSyncCloseRecv3(t *testing.T) {
+	v := 0
+	_ = v
+	c := make(chan int)
+	go func() {
+		v = 1
+		close(c)
+	}()
+	for range c {
+	}
+	v = 2
+}
+
+func TestRaceChanSyncCloseSend(t *testing.T) {
+	v := 0
+	_ = v
+	c := make(chan int)
+	go func() {
+		v = 1
+		close(c)
+	}()
+	func() {
+		defer func() {
+			recover()
+		}()
+		c <- 0
+	}()
+	v = 2
+}
+
+func TestRaceChanAsyncCloseSend(t *testing.T) {
+	v := 0
+	_ = v
+	c := make(chan int, 10)
+	go func() {
+		v = 1
+		close(c)
+	}()
+	func() {
+		defer func() {
+			recover()
+		}()
+		for {
+			c <- 0
+		}
+	}()
+	v = 2
+}
+
+func TestRaceChanCloseClose(t *testing.T) {
+	compl := make(chan bool, 2)
+	v1 := 0
+	v2 := 0
+	_ = v1 + v2
+	c := make(chan int)
+	go func() {
+		defer func() {
+			if recover() != nil {
+				v2 = 2
+			}
+			compl <- true
+		}()
+		v1 = 1
+		close(c)
+	}()
+	go func() {
+		defer func() {
+			if recover() != nil {
+				v1 = 2
+			}
+			compl <- true
+		}()
+		v2 = 1
+		close(c)
+	}()
+	<-compl
+	<-compl
+}
+
+func TestRaceChanSendLen(t *testing.T) {
+	v := 0
+	_ = v
+	c := make(chan int, 10)
+	go func() {
+		v = 1
+		c <- 1
+	}()
+	for len(c) == 0 {
+		runtime.Gosched()
+	}
+	v = 2
+}
+
+func TestRaceChanRecvLen(t *testing.T) {
+	v := 0
+	_ = v
+	c := make(chan int, 10)
+	c <- 1
+	go func() {
+		v = 1
+		<-c
+	}()
+	for len(c) != 0 {
+		runtime.Gosched()
+	}
+	v = 2
+}
+
+func TestRaceChanSendSend(t *testing.T) {
+	compl := make(chan bool, 2)
+	v1 := 0
+	v2 := 0
+	_ = v1 + v2
+	c := make(chan int, 1)
+	go func() {
+		v1 = 1
+		select {
+		case c <- 1:
+		default:
+			v2 = 2
+		}
+		compl <- true
+	}()
+	go func() {
+		v2 = 1
+		select {
+		case c <- 1:
+		default:
+			v1 = 2
+		}
+		compl <- true
+	}()
+	<-compl
+	<-compl
+}
+
+func TestNoRaceChanPtr(t *testing.T) {
+	type msg struct {
+		x int
+	}
+	c := make(chan *msg)
+	go func() {
+		c <- &msg{1}
+	}()
+	m := <-c
+	m.x = 2
+}
+
+func TestRaceChanWrongSend(t *testing.T) {
+	v1 := 0
+	v2 := 0
+	_ = v1 + v2
+	c := make(chan int, 2)
+	go func() {
+		v1 = 1
+		c <- 1
+	}()
+	go func() {
+		v2 = 2
+		c <- 2
+	}()
+	time.Sleep(1e7)
+	if <-c == 1 {
+		v2 = 3
+	} else {
+		v1 = 3
+	}
+}
+
+func TestRaceChanWrongClose(t *testing.T) {
+	v1 := 0
+	v2 := 0
+	_ = v1 + v2
+	c := make(chan int, 1)
+	done := make(chan bool)
+	go func() {
+		defer func() {
+			recover()
+		}()
+		v1 = 1
+		c <- 1
+		done <- true
+	}()
+	go func() {
+		time.Sleep(1e7)
+		v2 = 2
+		close(c)
+		done <- true
+	}()
+	time.Sleep(2e7)
+	if _, who := <-c; who {
+		v2 = 2
+	} else {
+		v1 = 2
+	}
+	<-done
+	<-done
+}
+
+func TestRaceChanSendClose(t *testing.T) {
+	compl := make(chan bool, 2)
+	c := make(chan int, 1)
+	go func() {
+		defer func() {
+			recover()
+			compl <- true
+		}()
+		c <- 1
+	}()
+	go func() {
+		time.Sleep(10 * time.Millisecond)
+		close(c)
+		compl <- true
+	}()
+	<-compl
+	<-compl
+}
+
+func TestRaceChanSendSelectClose(t *testing.T) {
+	compl := make(chan bool, 2)
+	c := make(chan int, 1)
+	c1 := make(chan int)
+	go func() {
+		defer func() {
+			recover()
+			compl <- true
+		}()
+		time.Sleep(10 * time.Millisecond)
+		select {
+		case c <- 1:
+		case <-c1:
+		}
+	}()
+	go func() {
+		close(c)
+		compl <- true
+	}()
+	<-compl
+	<-compl
+}
+
+func TestRaceSelectReadWriteAsync(t *testing.T) {
+	done := make(chan bool)
+	x := 0
+	c1 := make(chan int, 10)
+	c2 := make(chan int, 10)
+	c3 := make(chan int)
+	c2 <- 1
+	go func() {
+		select {
+		case c1 <- x: // read of x races with...
+		case c3 <- 1:
+		}
+		done <- true
+	}()
+	select {
+	case x = <-c2: // ... write to x here
+	case c3 <- 1:
+	}
+	<-done
+}
+
+func TestRaceSelectReadWriteSync(t *testing.T) {
+	done := make(chan bool)
+	x := 0
+	c1 := make(chan int)
+	c2 := make(chan int)
+	c3 := make(chan int)
+	// make c1 and c2 ready for communication
+	go func() {
+		<-c1
+	}()
+	go func() {
+		c2 <- 1
+	}()
+	go func() {
+		select {
+		case c1 <- x: // read of x races with...
+		case c3 <- 1:
+		}
+		done <- true
+	}()
+	select {
+	case x = <-c2: // ... write to x here
+	case c3 <- 1:
+	}
+	<-done
+}
+
+func TestNoRaceSelectReadWriteAsync(t *testing.T) {
+	done := make(chan bool)
+	x := 0
+	c1 := make(chan int)
+	c2 := make(chan int)
+	go func() {
+		select {
+		case c1 <- x: // read of x does not race with...
+		case c2 <- 1:
+		}
+		done <- true
+	}()
+	select {
+	case x = <-c1: // ... write to x here
+	case c2 <- 1:
+	}
+	<-done
+}
+
+func TestRaceChanReadWriteAsync(t *testing.T) {
+	done := make(chan bool)
+	c1 := make(chan int, 10)
+	c2 := make(chan int, 10)
+	c2 <- 10
+	x := 0
+	go func() {
+		c1 <- x // read of x races with...
+		done <- true
+	}()
+	x = <-c2 // ... write to x here
+	<-done
+}
+
+func TestRaceChanReadWriteSync(t *testing.T) {
+	done := make(chan bool)
+	c1 := make(chan int)
+	c2 := make(chan int)
+	// make c1 and c2 ready for communication
+	go func() {
+		<-c1
+	}()
+	go func() {
+		c2 <- 10
+	}()
+	x := 0
+	go func() {
+		c1 <- x // read of x races with...
+		done <- true
+	}()
+	x = <-c2 // ... write to x here
+	<-done
+}
+
+func TestNoRaceChanReadWriteAsync(t *testing.T) {
+	done := make(chan bool)
+	c1 := make(chan int, 10)
+	x := 0
+	go func() {
+		c1 <- x // read of x does not race with...
+		done <- true
+	}()
+	x = <-c1 // ... write to x here
+	<-done
+}
+
+func TestNoRaceProducerConsumerUnbuffered(t *testing.T) {
+	type Task struct {
+		f    func()
+		done chan bool
+	}
+
+	queue := make(chan Task)
+
+	go func() {
+		t := <-queue
+		t.f()
+		t.done <- true
+	}()
+
+	doit := func(f func()) {
+		done := make(chan bool, 1)
+		queue <- Task{f, done}
+		<-done
+	}
+
+	x := 0
+	doit(func() {
+		x = 1
+	})
+	_ = x
+}
+
+func TestRaceChanItselfSend(t *testing.T) {
+	compl := make(chan bool, 1)
+	c := make(chan int, 10)
+	go func() {
+		c <- 0
+		compl <- true
+	}()
+	c = make(chan int, 20)
+	<-compl
+}
+
+func TestRaceChanItselfRecv(t *testing.T) {
+	compl := make(chan bool, 1)
+	c := make(chan int, 10)
+	c <- 1
+	go func() {
+		<-c
+		compl <- true
+	}()
+	time.Sleep(1e7)
+	c = make(chan int, 20)
+	<-compl
+}
+
+func TestRaceChanItselfNil(t *testing.T) {
+	c := make(chan int, 10)
+	go func() {
+		c <- 0
+	}()
+	time.Sleep(1e7)
+	c = nil
+	_ = c
+}
+
+func TestRaceChanItselfClose(t *testing.T) {
+	compl := make(chan bool, 1)
+	c := make(chan int)
+	go func() {
+		close(c)
+		compl <- true
+	}()
+	c = make(chan int)
+	<-compl
+}
+
+func TestRaceChanItselfLen(t *testing.T) {
+	compl := make(chan bool, 1)
+	c := make(chan int)
+	go func() {
+		_ = len(c)
+		compl <- true
+	}()
+	c = make(chan int)
+	<-compl
+}
+
+func TestRaceChanItselfCap(t *testing.T) {
+	compl := make(chan bool, 1)
+	c := make(chan int)
+	go func() {
+		_ = cap(c)
+		compl <- true
+	}()
+	c = make(chan int)
+	<-compl
+}
+
+func TestNoRaceChanCloseLen(t *testing.T) {
+	c := make(chan int, 10)
+	r := make(chan int, 10)
+	go func() {
+		r <- len(c)
+	}()
+	go func() {
+		close(c)
+		r <- 0
+	}()
+	<-r
+	<-r
+}
+
+func TestNoRaceChanCloseCap(t *testing.T) {
+	c := make(chan int, 10)
+	r := make(chan int, 10)
+	go func() {
+		r <- cap(c)
+	}()
+	go func() {
+		close(c)
+		r <- 0
+	}()
+	<-r
+	<-r
+}
+
+func TestRaceChanCloseSend(t *testing.T) {
+	compl := make(chan bool, 1)
+	c := make(chan int, 10)
+	go func() {
+		close(c)
+		compl <- true
+	}()
+	c <- 0
+	<-compl
+}
+
+func TestNoRaceChanMutex(t *testing.T) {
+	done := make(chan struct{})
+	mtx := make(chan struct{}, 1)
+	data := 0
+	_ = data
+	go func() {
+		mtx <- struct{}{}
+		data = 42
+		<-mtx
+		done <- struct{}{}
+	}()
+	mtx <- struct{}{}
+	data = 43
+	<-mtx
+	<-done
+}
+
+func TestNoRaceSelectMutex(t *testing.T) {
+	done := make(chan struct{})
+	mtx := make(chan struct{}, 1)
+	aux := make(chan bool)
+	data := 0
+	_ = data
+	go func() {
+		select {
+		case mtx <- struct{}{}:
+		case <-aux:
+		}
+		data = 42
+		select {
+		case <-mtx:
+		case <-aux:
+		}
+		done <- struct{}{}
+	}()
+	select {
+	case mtx <- struct{}{}:
+	case <-aux:
+	}
+	data = 43
+	select {
+	case <-mtx:
+	case <-aux:
+	}
+	<-done
+}
+
+func TestRaceChanSem(t *testing.T) {
+	done := make(chan struct{})
+	mtx := make(chan bool, 2)
+	data := 0
+	_ = data
+	go func() {
+		mtx <- true
+		data = 42
+		<-mtx
+		done <- struct{}{}
+	}()
+	mtx <- true
+	data = 43
+	<-mtx
+	<-done
+}
+
+func TestNoRaceChanWaitGroup(t *testing.T) {
+	const N = 10
+	chanWg := make(chan bool, N/2)
+	data := make([]int, N)
+	for i := 0; i < N; i++ {
+		chanWg <- true
+		go func(i int) {
+			data[i] = 42
+			<-chanWg
+		}(i)
+	}
+	for i := 0; i < cap(chanWg); i++ {
+		chanWg <- true
+	}
+	for i := 0; i < N; i++ {
+		_ = data[i]
+	}
+}
+
+// Test that sender synchronizes with receiver even if the sender was blocked.
+func TestNoRaceBlockedSendSync(t *testing.T) {
+	c := make(chan *int, 1)
+	c <- nil
+	go func() {
+		i := 42
+		c <- &i
+	}()
+	// Give the sender time to actually block.
+	// This sleep is completely optional: race report must not be printed
+	// regardless of whether the sender actually blocks or not.
+	// It cannot lead to flakiness.
+	time.Sleep(10 * time.Millisecond)
+	<-c
+	p := <-c
+	if *p != 42 {
+		t.Fatal()
+	}
+}
+
+// The same as TestNoRaceBlockedSendSync above, but sender unblock happens in a select.
+func TestNoRaceBlockedSelectSendSync(t *testing.T) {
+	c := make(chan *int, 1)
+	c <- nil
+	go func() {
+		i := 42
+		c <- &i
+	}()
+	time.Sleep(10 * time.Millisecond)
+	<-c
+	select {
+	case p := <-c:
+		if *p != 42 {
+			t.Fatal()
+		}
+	case <-make(chan int):
+	}
+}
+
+// Test that close synchronizes with a read from the empty closed channel.
+// See https://golang.org/issue/36714.
+func TestNoRaceCloseHappensBeforeRead(t *testing.T) {
+	for i := 0; i < 100; i++ {
+		var loc int
+		var write = make(chan struct{})
+		var read = make(chan struct{})
+
+		go func() {
+			select {
+			case <-write:
+				_ = loc
+			default:
+			}
+			close(read)
+		}()
+
+		go func() {
+			loc = 1
+			close(write)
+		}()
+
+		<-read
+	}
+}
+
+// Test that we call the proper race detector function when c.elemsize==0.
+// See https://github.com/golang/go/issues/42598
+func TestNoRaceElemSize0(t *testing.T) {
+	var x, y int
+	var c = make(chan struct{}, 2)
+	c <- struct{}{}
+	c <- struct{}{}
+	go func() {
+		x += 1
+		<-c
+	}()
+	go func() {
+		y += 1
+		<-c
+	}()
+	time.Sleep(10 * time.Millisecond)
+	c <- struct{}{}
+	c <- struct{}{}
+	x += 1
+	y += 1
+}

src/runtime/race/testdata/comp_test.go

@@ -0,0 +1,186 @@
+// Copyright 2012 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 race_test
+
+import (
+	"testing"
+)
+
+type P struct {
+	x, y int
+}
+
+type S struct {
+	s1, s2 P
+}
+
+func TestNoRaceComp(t *testing.T) {
+	c := make(chan bool, 1)
+	var s S
+	go func() {
+		s.s2.x = 1
+		c <- true
+	}()
+	s.s2.y = 2
+	<-c
+}
+
+func TestNoRaceComp2(t *testing.T) {
+	c := make(chan bool, 1)
+	var s S
+	go func() {
+		s.s1.x = 1
+		c <- true
+	}()
+	s.s1.y = 2
+	<-c
+}
+
+func TestRaceComp(t *testing.T) {
+	c := make(chan bool, 1)
+	var s S
+	go func() {
+		s.s2.y = 1
+		c <- true
+	}()
+	s.s2.y = 2
+	<-c
+}
+
+func TestRaceComp2(t *testing.T) {
+	c := make(chan bool, 1)
+	var s S
+	go func() {
+		s.s1.x = 1
+		c <- true
+	}()
+	s = S{}
+	<-c
+}
+
+func TestRaceComp3(t *testing.T) {
+	c := make(chan bool, 1)
+	var s S
+	go func() {
+		s.s2.y = 1
+		c <- true
+	}()
+	s = S{}
+	<-c
+}
+
+func TestRaceCompArray(t *testing.T) {
+	c := make(chan bool, 1)
+	s := make([]S, 10)
+	x := 4
+	go func() {
+		s[x].s2.y = 1
+		c <- true
+	}()
+	x = 5
+	<-c
+}
+
+type P2 P
+type S2 S
+
+func TestRaceConv1(t *testing.T) {
+	c := make(chan bool, 1)
+	var p P2
+	go func() {
+		p.x = 1
+		c <- true
+	}()
+	_ = P(p).x
+	<-c
+}
+
+func TestRaceConv2(t *testing.T) {
+	c := make(chan bool, 1)
+	var p P2
+	go func() {
+		p.x = 1
+		c <- true
+	}()
+	ptr := &p
+	_ = P(*ptr).x
+	<-c
+}
+
+func TestRaceConv3(t *testing.T) {
+	c := make(chan bool, 1)
+	var s S2
+	go func() {
+		s.s1.x = 1
+		c <- true
+	}()
+	_ = P2(S(s).s1).x
+	<-c
+}
+
+type X struct {
+	V [4]P
+}
+
+type X2 X
+
+func TestRaceConv4(t *testing.T) {
+	c := make(chan bool, 1)
+	var x X2
+	go func() {
+		x.V[1].x = 1
+		c <- true
+	}()
+	_ = P2(X(x).V[1]).x
+	<-c
+}
+
+type Ptr struct {
+	s1, s2 *P
+}
+
+func TestNoRaceCompPtr(t *testing.T) {
+	c := make(chan bool, 1)
+	p := Ptr{&P{}, &P{}}
+	go func() {
+		p.s1.x = 1
+		c <- true
+	}()
+	p.s1.y = 2
+	<-c
+}
+
+func TestNoRaceCompPtr2(t *testing.T) {
+	c := make(chan bool, 1)
+	p := Ptr{&P{}, &P{}}
+	go func() {
+		p.s1.x = 1
+		c <- true
+	}()
+	_ = p
+	<-c
+}
+
+func TestRaceCompPtr(t *testing.T) {
+	c := make(chan bool, 1)
+	p := Ptr{&P{}, &P{}}
+	go func() {
+		p.s2.x = 1
+		c <- true
+	}()
+	p.s2.x = 2
+	<-c
+}
+
+func TestRaceCompPtr2(t *testing.T) {
+	c := make(chan bool, 1)
+	p := Ptr{&P{}, &P{}}
+	go func() {
+		p.s2.x = 1
+		c <- true
+	}()
+	p.s2 = &P{}
+	<-c
+}

src/runtime/race/testdata/finalizer_test.go

@@ -0,0 +1,68 @@
+// Copyright 2012 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 race_test
+
+import (
+	"runtime"
+	"sync"
+	"testing"
+	"time"
+)
+
+func TestNoRaceFin(t *testing.T) {
+	c := make(chan bool)
+	go func() {
+		x := new(string)
+		runtime.SetFinalizer(x, func(x *string) {
+			*x = "foo"
+		})
+		*x = "bar"
+		c <- true
+	}()
+	<-c
+	runtime.GC()
+	time.Sleep(100 * time.Millisecond)
+}
+
+var finVar struct {
+	sync.Mutex
+	cnt int
+}
+
+func TestNoRaceFinGlobal(t *testing.T) {
+	c := make(chan bool)
+	go func() {
+		x := new(string)
+		runtime.SetFinalizer(x, func(x *string) {
+			finVar.Lock()
+			finVar.cnt++
+			finVar.Unlock()
+		})
+		c <- true
+	}()
+	<-c
+	runtime.GC()
+	time.Sleep(100 * time.Millisecond)
+	finVar.Lock()
+	finVar.cnt++
+	finVar.Unlock()
+}
+
+func TestRaceFin(t *testing.T) {
+	c := make(chan bool)
+	y := 0
+	_ = y
+	go func() {
+		x := new(string)
+		runtime.SetFinalizer(x, func(x *string) {
+			y = 42
+		})
+		c <- true
+	}()
+	<-c
+	runtime.GC()
+	time.Sleep(100 * time.Millisecond)
+	y = 66
+}

src/runtime/race/testdata/io_test.go

@@ -0,0 +1,75 @@
+// Copyright 2012 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 race_test
+
+import (
+	"fmt"
+	"net"
+	"net/http"
+	"os"
+	"path/filepath"
+	"sync"
+	"testing"
+	"time"
+)
+
+func TestNoRaceIOFile(t *testing.T) {
+	x := 0
+	path := t.TempDir()
+	fname := filepath.Join(path, "data")
+	go func() {
+		x = 42
+		f, _ := os.Create(fname)
+		f.Write([]byte("done"))
+		f.Close()
+	}()
+	for {
+		f, err := os.Open(fname)
+		if err != nil {
+			time.Sleep(1e6)
+			continue
+		}
+		buf := make([]byte, 100)
+		count, err := f.Read(buf)
+		if count == 0 {
+			time.Sleep(1e6)
+			continue
+		}
+		break
+	}
+	_ = x
+}
+
+var (
+	regHandler  sync.Once
+	handlerData int
+)
+
+func TestNoRaceIOHttp(t *testing.T) {
+	regHandler.Do(func() {
+		http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
+			handlerData++
+			fmt.Fprintf(w, "test")
+			handlerData++
+		})
+	})
+	ln, err := net.Listen("tcp", "127.0.0.1:0")
+	if err != nil {
+		t.Fatalf("net.Listen: %v", err)
+	}
+	defer ln.Close()
+	go http.Serve(ln, nil)
+	handlerData++
+	_, err = http.Get("http://" + ln.Addr().String())
+	if err != nil {
+		t.Fatalf("http.Get: %v", err)
+	}
+	handlerData++
+	_, err = http.Get("http://" + ln.Addr().String())
+	if err != nil {
+		t.Fatalf("http.Get: %v", err)
+	}
+	handlerData++
+}

src/runtime/race/testdata/issue12225_test.go

@@ -0,0 +1,20 @@
+// Copyright 2015 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 race_test
+
+import "unsafe"
+
+// golang.org/issue/12225
+// The test is that this compiles at all.
+
+//go:noinline
+func convert(s string) []byte {
+	return []byte(s)
+}
+
+func issue12225() {
+	println(*(*int)(unsafe.Pointer(&convert("")[0])))
+	println(*(*int)(unsafe.Pointer(&[]byte("")[0])))
+}

src/runtime/race/testdata/issue12664_test.go

@@ -0,0 +1,76 @@
+// Copyright 2015 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 race_test
+
+import (
+	"fmt"
+	"testing"
+)
+
+var issue12664 = "hi"
+
+func TestRaceIssue12664(t *testing.T) {
+	c := make(chan struct{})
+	go func() {
+		issue12664 = "bye"
+		close(c)
+	}()
+	fmt.Println(issue12664)
+	<-c
+}
+
+type MyI interface {
+	foo()
+}
+
+type MyT int
+
+func (MyT) foo() {
+}
+
+var issue12664_2 MyT = 0
+
+func TestRaceIssue12664_2(t *testing.T) {
+	c := make(chan struct{})
+	go func() {
+		issue12664_2 = 1
+		close(c)
+	}()
+	func(x MyI) {
+		// Never true, but prevents inlining.
+		if x.(MyT) == -1 {
+			close(c)
+		}
+	}(issue12664_2)
+	<-c
+}
+
+var issue12664_3 MyT = 0
+
+func TestRaceIssue12664_3(t *testing.T) {
+	c := make(chan struct{})
+	go func() {
+		issue12664_3 = 1
+		close(c)
+	}()
+	var r MyT
+	var i any = r
+	issue12664_3 = i.(MyT)
+	<-c
+}
+
+var issue12664_4 MyT = 0
+
+func TestRaceIssue12664_4(t *testing.T) {
+	c := make(chan struct{})
+	go func() {
+		issue12664_4 = 1
+		close(c)
+	}()
+	var r MyT
+	var i MyI = r
+	issue12664_4 = i.(MyT)
+	<-c
+}

src/runtime/race/testdata/issue13264_test.go

@@ -0,0 +1,13 @@
+// Copyright 2015 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 race_test
+
+// golang.org/issue/13264
+// The test is that this compiles at all.
+
+func issue13264() {
+	for ; ; []map[int]int{}[0][0] = 0 {
+	}
+}

src/runtime/race/testdata/map_test.go

@@ -0,0 +1,335 @@
+// Copyright 2012 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 race_test
+
+import (
+	"testing"
+)
+
+func TestRaceMapRW(t *testing.T) {
+	m := make(map[int]int)
+	ch := make(chan bool, 1)
+	go func() {
+		_ = m[1]
+		ch <- true
+	}()
+	m[1] = 1
+	<-ch
+}
+
+func TestRaceMapRW2(t *testing.T) {
+	m := make(map[int]int)
+	ch := make(chan bool, 1)
+	go func() {
+		_, _ = m[1]
+		ch <- true
+	}()
+	m[1] = 1
+	<-ch
+}
+
+func TestRaceMapRWArray(t *testing.T) {
+	// Check instrumentation of unaddressable arrays (issue 4578).
+	m := make(map[int][2]int)
+	ch := make(chan bool, 1)
+	go func() {
+		_ = m[1][1]
+		ch <- true
+	}()
+	m[2] = [2]int{1, 2}
+	<-ch
+}
+
+func TestNoRaceMapRR(t *testing.T) {
+	m := make(map[int]int)
+	ch := make(chan bool, 1)
+	go func() {
+		_, _ = m[1]
+		ch <- true
+	}()
+	_ = m[1]
+	<-ch
+}
+
+func TestRaceMapRange(t *testing.T) {
+	m := make(map[int]int)
+	ch := make(chan bool, 1)
+	go func() {
+		for range m {
+		}
+		ch <- true
+	}()
+	m[1] = 1
+	<-ch
+}
+
+func TestRaceMapRange2(t *testing.T) {
+	m := make(map[int]int)
+	ch := make(chan bool, 1)
+	go func() {
+		for range m {
+		}
+		ch <- true
+	}()
+	m[1] = 1
+	<-ch
+}
+
+func TestNoRaceMapRangeRange(t *testing.T) {
+	m := make(map[int]int)
+	// now the map is not empty and range triggers an event
+	// should work without this (as in other tests)
+	// so it is suspicious if this test passes and others don't
+	m[0] = 0
+	ch := make(chan bool, 1)
+	go func() {
+		for range m {
+		}
+		ch <- true
+	}()
+	for range m {
+	}
+	<-ch
+}
+
+func TestRaceMapLen(t *testing.T) {
+	m := make(map[string]bool)
+	ch := make(chan bool, 1)
+	go func() {
+		_ = len(m)
+		ch <- true
+	}()
+	m[""] = true
+	<-ch
+}
+
+func TestRaceMapDelete(t *testing.T) {
+	m := make(map[string]bool)
+	ch := make(chan bool, 1)
+	go func() {
+		delete(m, "")
+		ch <- true
+	}()
+	m[""] = true
+	<-ch
+}
+
+func TestRaceMapLenDelete(t *testing.T) {
+	m := make(map[string]bool)
+	ch := make(chan bool, 1)
+	go func() {
+		delete(m, "a")
+		ch <- true
+	}()
+	_ = len(m)
+	<-ch
+}
+
+func TestRaceMapVariable(t *testing.T) {
+	ch := make(chan bool, 1)
+	m := make(map[int]int)
+	_ = m
+	go func() {
+		m = make(map[int]int)
+		ch <- true
+	}()
+	m = make(map[int]int)
+	<-ch
+}
+
+func TestRaceMapVariable2(t *testing.T) {
+	ch := make(chan bool, 1)
+	m := make(map[int]int)
+	go func() {
+		m[1] = 1
+		ch <- true
+	}()
+	m = make(map[int]int)
+	<-ch
+}
+
+func TestRaceMapVariable3(t *testing.T) {
+	ch := make(chan bool, 1)
+	m := make(map[int]int)
+	go func() {
+		_ = m[1]
+		ch <- true
+	}()
+	m = make(map[int]int)
+	<-ch
+}
+
+type Big struct {
+	x [17]int32
+}
+
+func TestRaceMapLookupPartKey(t *testing.T) {
+	k := &Big{}
+	m := make(map[Big]bool)
+	ch := make(chan bool, 1)
+	go func() {
+		k.x[8] = 1
+		ch <- true
+	}()
+	_ = m[*k]
+	<-ch
+}
+
+func TestRaceMapLookupPartKey2(t *testing.T) {
+	k := &Big{}
+	m := make(map[Big]bool)
+	ch := make(chan bool, 1)
+	go func() {
+		k.x[8] = 1
+		ch <- true
+	}()
+	_, _ = m[*k]
+	<-ch
+}
+func TestRaceMapDeletePartKey(t *testing.T) {
+	k := &Big{}
+	m := make(map[Big]bool)
+	ch := make(chan bool, 1)
+	go func() {
+		k.x[8] = 1
+		ch <- true
+	}()
+	delete(m, *k)
+	<-ch
+}
+
+func TestRaceMapInsertPartKey(t *testing.T) {
+	k := &Big{}
+	m := make(map[Big]bool)
+	ch := make(chan bool, 1)
+	go func() {
+		k.x[8] = 1
+		ch <- true
+	}()
+	m[*k] = true
+	<-ch
+}
+
+func TestRaceMapInsertPartVal(t *testing.T) {
+	v := &Big{}
+	m := make(map[int]Big)
+	ch := make(chan bool, 1)
+	go func() {
+		v.x[8] = 1
+		ch <- true
+	}()
+	m[1] = *v
+	<-ch
+}
+
+// Test for issue 7561.
+func TestRaceMapAssignMultipleReturn(t *testing.T) {
+	connect := func() (int, error) { return 42, nil }
+	conns := make(map[int][]int)
+	conns[1] = []int{0}
+	ch := make(chan bool, 1)
+	var err error
+	_ = err
+	go func() {
+		conns[1][0], err = connect()
+		ch <- true
+	}()
+	x := conns[1][0]
+	_ = x
+	<-ch
+}
+
+// BigKey and BigVal must be larger than 256 bytes,
+// so that compiler sets KindGCProg for them.
+type BigKey [1000]*int
+
+type BigVal struct {
+	x int
+	y [1000]*int
+}
+
+func TestRaceMapBigKeyAccess1(t *testing.T) {
+	m := make(map[BigKey]int)
+	var k BigKey
+	ch := make(chan bool, 1)
+	go func() {
+		_ = m[k]
+		ch <- true
+	}()
+	k[30] = new(int)
+	<-ch
+}
+
+func TestRaceMapBigKeyAccess2(t *testing.T) {
+	m := make(map[BigKey]int)
+	var k BigKey
+	ch := make(chan bool, 1)
+	go func() {
+		_, _ = m[k]
+		ch <- true
+	}()
+	k[30] = new(int)
+	<-ch
+}
+
+func TestRaceMapBigKeyInsert(t *testing.T) {
+	m := make(map[BigKey]int)
+	var k BigKey
+	ch := make(chan bool, 1)
+	go func() {
+		m[k] = 1
+		ch <- true
+	}()
+	k[30] = new(int)
+	<-ch
+}
+
+func TestRaceMapBigKeyDelete(t *testing.T) {
+	m := make(map[BigKey]int)
+	var k BigKey
+	ch := make(chan bool, 1)
+	go func() {
+		delete(m, k)
+		ch <- true
+	}()
+	k[30] = new(int)
+	<-ch
+}
+
+func TestRaceMapBigValInsert(t *testing.T) {
+	m := make(map[int]BigVal)
+	var v BigVal
+	ch := make(chan bool, 1)
+	go func() {
+		m[1] = v
+		ch <- true
+	}()
+	v.y[30] = new(int)
+	<-ch
+}
+
+func TestRaceMapBigValAccess1(t *testing.T) {
+	m := make(map[int]BigVal)
+	var v BigVal
+	ch := make(chan bool, 1)
+	go func() {
+		v = m[1]
+		ch <- true
+	}()
+	v.y[30] = new(int)
+	<-ch
+}
+
+func TestRaceMapBigValAccess2(t *testing.T) {
+	m := make(map[int]BigVal)
+	var v BigVal
+	ch := make(chan bool, 1)
+	go func() {
+		v, _ = m[1]
+		ch <- true
+	}()
+	v.y[30] = new(int)
+	<-ch
+}

src/runtime/race/testdata/mutex_test.go

@@ -0,0 +1,150 @@
+// Copyright 2012 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 race_test
+
+import (
+	"sync"
+	"testing"
+	"time"
+)
+
+func TestNoRaceMutex(t *testing.T) {
+	var mu sync.Mutex
+	var x int16 = 0
+	_ = x
+	ch := make(chan bool, 2)
+	go func() {
+		mu.Lock()
+		defer mu.Unlock()
+		x = 1
+		ch <- true
+	}()
+	go func() {
+		mu.Lock()
+		x = 2
+		mu.Unlock()
+		ch <- true
+	}()
+	<-ch
+	<-ch
+}
+
+func TestRaceMutex(t *testing.T) {
+	var mu sync.Mutex
+	var x int16 = 0
+	_ = x
+	ch := make(chan bool, 2)
+	go func() {
+		x = 1
+		mu.Lock()
+		defer mu.Unlock()
+		ch <- true
+	}()
+	go func() {
+		x = 2
+		mu.Lock()
+		mu.Unlock()
+		ch <- true
+	}()
+	<-ch
+	<-ch
+}
+
+func TestRaceMutex2(t *testing.T) {
+	var mu1 sync.Mutex
+	var mu2 sync.Mutex
+	var x int8 = 0
+	_ = x
+	ch := make(chan bool, 2)
+	go func() {
+		mu1.Lock()
+		defer mu1.Unlock()
+		x = 1
+		ch <- true
+	}()
+	go func() {
+		mu2.Lock()
+		x = 2
+		mu2.Unlock()
+		ch <- true
+	}()
+	<-ch
+	<-ch
+}
+
+func TestNoRaceMutexPureHappensBefore(t *testing.T) {
+	var mu sync.Mutex
+	var x int16 = 0
+	_ = x
+	written := false
+	ch := make(chan bool, 2)
+	go func() {
+		x = 1
+		mu.Lock()
+		written = true
+		mu.Unlock()
+		ch <- true
+	}()
+	go func() {
+		time.Sleep(100 * time.Microsecond)
+		mu.Lock()
+		for !written {
+			mu.Unlock()
+			time.Sleep(100 * time.Microsecond)
+			mu.Lock()
+		}
+		mu.Unlock()
+		x = 1
+		ch <- true
+	}()
+	<-ch
+	<-ch
+}
+
+func TestNoRaceMutexSemaphore(t *testing.T) {
+	var mu sync.Mutex
+	ch := make(chan bool, 2)
+	x := 0
+	_ = x
+	mu.Lock()
+	go func() {
+		x = 1
+		mu.Unlock()
+		ch <- true
+	}()
+	go func() {
+		mu.Lock()
+		x = 2
+		mu.Unlock()
+		ch <- true
+	}()
+	<-ch
+	<-ch
+}
+
+// from doc/go_mem.html
+func TestNoRaceMutexExampleFromHtml(t *testing.T) {
+	var l sync.Mutex
+	a := ""
+
+	l.Lock()
+	go func() {
+		a = "hello, world"
+		l.Unlock()
+	}()
+	l.Lock()
+	_ = a
+}
+
+func TestRaceMutexOverwrite(t *testing.T) {
+	c := make(chan bool, 1)
+	var mu sync.Mutex
+	go func() {
+		mu = sync.Mutex{}
+		c <- true
+	}()
+	mu.Lock()
+	<-c
+}

src/runtime/race/testdata/pool_test.go

@@ -0,0 +1,47 @@
+// Copyright 2016 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 race_test
+
+import (
+	"sync"
+	"testing"
+	"time"
+)
+
+func TestRacePool(t *testing.T) {
+	// Pool randomly drops the argument on the floor during Put.
+	// Repeat so that at least one iteration gets reuse.
+	for i := 0; i < 10; i++ {
+		c := make(chan int)
+		p := &sync.Pool{New: func() any { return make([]byte, 10) }}
+		x := p.Get().([]byte)
+		x[0] = 1
+		p.Put(x)
+		go func() {
+			y := p.Get().([]byte)
+			y[0] = 2
+			c <- 1
+		}()
+		x[0] = 3
+		<-c
+	}
+}
+
+func TestNoRacePool(t *testing.T) {
+	for i := 0; i < 10; i++ {
+		p := &sync.Pool{New: func() any { return make([]byte, 10) }}
+		x := p.Get().([]byte)
+		x[0] = 1
+		p.Put(x)
+		go func() {
+			y := p.Get().([]byte)
+			y[0] = 2
+			p.Put(y)
+		}()
+		time.Sleep(100 * time.Millisecond)
+		x = p.Get().([]byte)
+		x[0] = 3
+	}
+}

src/runtime/race/testdata/rangefunc_test.go

@@ -0,0 +1,77 @@
+// 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.
+
+//go:build goexperiment.rangefunc
+
+package race_test
+
+import (
+	"runtime"
+	"sync/atomic"
+	"testing"
+)
+
+type Seq2[T1, T2 any] func(yield func(T1, T2) bool)
+
+// ofSliceIndex returns a Seq over the elements of s. It is equivalent
+// to range s, except that it splits s into two halves and iterates
+// in two separate goroutines.  This is racy if yield is racy, and yield
+// will be racy if it contains an early exit.
+func ofSliceIndex[T any, S ~[]T](s S) Seq2[int, T] {
+	return func(yield func(int, T) bool) {
+		c := make(chan bool, 2)
+		var done atomic.Bool
+		go func() {
+			for i := 0; i < len(s)/2; i++ {
+				if !done.Load() && !yield(i, s[i]) {
+					done.Store(true)
+					c <- false
+				}
+			}
+			c <- true
+		}()
+		go func() {
+			for i := len(s) / 2; i < len(s); i++ {
+				if !done.Load() && !yield(i, s[i]) {
+					done.Store(true)
+					c <- false
+				}
+			}
+			c <- true
+			return
+		}()
+		if !<-c {
+			return
+		}
+		<-c
+	}
+}
+
+// foo is racy, or not, depending on the value of v
+// (0-4 == racy, otherwise, not racy).
+func foo(v int) int64 {
+	var asum atomic.Int64
+	for i, x := range ofSliceIndex([]int64{1, 2, 3, 4, 5, 6, 7, 8, 9, 10}) {
+		if i%5 == v {
+			break
+		}
+		asum.Add(x) // don't race on asum
+		runtime.Gosched()
+	}
+	return 100 + asum.Load()
+}
+
+// TestRaceRangeFuncIterator races because x%5 can be equal to 4,
+// therefore foo can early exit.
+func TestRaceRangeFuncIterator(t *testing.T) {
+	x := foo(4)
+	t.Logf("foo(4)=%d", x)
+}
+
+// TestNoRaceRangeFuncIterator does not race because x%5 is never 5,
+// therefore foo's loop will not exit early, and this it will not race.
+func TestNoRaceRangeFuncIterator(t *testing.T) {
+	x := foo(5)
+	t.Logf("foo(5)=%d", x)
+}

src/runtime/race/testdata/reflect_test.go

@@ -0,0 +1,46 @@
+// Copyright 2016 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 race_test
+
+import (
+	"reflect"
+	"testing"
+)
+
+func TestRaceReflectRW(t *testing.T) {
+	ch := make(chan bool, 1)
+	i := 0
+	v := reflect.ValueOf(&i)
+	go func() {
+		v.Elem().Set(reflect.ValueOf(1))
+		ch <- true
+	}()
+	_ = v.Elem().Int()
+	<-ch
+}
+
+func TestRaceReflectWW(t *testing.T) {
+	ch := make(chan bool, 1)
+	i := 0
+	v := reflect.ValueOf(&i)
+	go func() {
+		v.Elem().Set(reflect.ValueOf(1))
+		ch <- true
+	}()
+	v.Elem().Set(reflect.ValueOf(2))
+	<-ch
+}
+
+func TestRaceReflectCopyWW(t *testing.T) {
+	ch := make(chan bool, 1)
+	a := make([]byte, 2)
+	v := reflect.ValueOf(a)
+	go func() {
+		reflect.Copy(v, v)
+		ch <- true
+	}()
+	reflect.Copy(v, v)
+	<-ch
+}

src/runtime/race/testdata/regression_test.go

@@ -0,0 +1,189 @@
+// Copyright 2012 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.
+
+// Code patterns that caused problems in the past.
+
+package race_test
+
+import (
+	"testing"
+)
+
+type LogImpl struct {
+	x int
+}
+
+func NewLog() (l LogImpl) {
+	c := make(chan bool)
+	go func() {
+		_ = l
+		c <- true
+	}()
+	l = LogImpl{}
+	<-c
+	return
+}
+
+var _ LogImpl = NewLog()
+
+func MakeMap() map[int]int {
+	return make(map[int]int)
+}
+
+func InstrumentMapLen() {
+	_ = len(MakeMap())
+}
+
+func InstrumentMapLen2() {
+	m := make(map[int]map[int]int)
+	_ = len(m[0])
+}
+
+func InstrumentMapLen3() {
+	m := make(map[int]*map[int]int)
+	_ = len(*m[0])
+}
+
+func TestRaceUnaddressableMapLen(t *testing.T) {
+	m := make(map[int]map[int]int)
+	ch := make(chan int, 1)
+	m[0] = make(map[int]int)
+	go func() {
+		_ = len(m[0])
+		ch <- 0
+	}()
+	m[0][0] = 1
+	<-ch
+}
+
+type Rect struct {
+	x, y int
+}
+
+type Image struct {
+	min, max Rect
+}
+
+//go:noinline
+func NewImage() Image {
+	return Image{}
+}
+
+func AddrOfTemp() {
+	_ = NewImage().min
+}
+
+type TypeID int
+
+func (t *TypeID) encodeType(x int) (tt TypeID, err error) {
+	switch x {
+	case 0:
+		return t.encodeType(x * x)
+	}
+	return 0, nil
+}
+
+type stack []int
+
+func (s *stack) push(x int) {
+	*s = append(*s, x)
+}
+
+func (s *stack) pop() int {
+	i := len(*s)
+	n := (*s)[i-1]
+	*s = (*s)[:i-1]
+	return n
+}
+
+func TestNoRaceStackPushPop(t *testing.T) {
+	var s stack
+	go func(s *stack) {}(&s)
+	s.push(1)
+	x := s.pop()
+	_ = x
+}
+
+type RpcChan struct {
+	c chan bool
+}
+
+var makeChanCalls int
+
+//go:noinline
+func makeChan() *RpcChan {
+	makeChanCalls++
+	c := &RpcChan{make(chan bool, 1)}
+	c.c <- true
+	return c
+}
+
+func call() bool {
+	x := <-makeChan().c
+	return x
+}
+
+func TestNoRaceRpcChan(t *testing.T) {
+	makeChanCalls = 0
+	_ = call()
+	if makeChanCalls != 1 {
+		t.Fatalf("makeChanCalls %d, expected 1\n", makeChanCalls)
+	}
+}
+
+func divInSlice() {
+	v := make([]int64, 10)
+	i := 1
+	_ = v[(i*4)/3]
+}
+
+func TestNoRaceReturn(t *testing.T) {
+	c := make(chan int)
+	noRaceReturn(c)
+	<-c
+}
+
+// Return used to do an implicit a = a, causing a read/write race
+// with the goroutine. Compiler has an optimization to avoid that now.
+// See issue 4014.
+func noRaceReturn(c chan int) (a, b int) {
+	a = 42
+	go func() {
+		_ = a
+		c <- 1
+	}()
+	return a, 10
+}
+
+func issue5431() {
+	var p **inltype
+	if inlinetest(p).x && inlinetest(p).y {
+	} else if inlinetest(p).x || inlinetest(p).y {
+	}
+}
+
+type inltype struct {
+	x, y bool
+}
+
+func inlinetest(p **inltype) *inltype {
+	return *p
+}
+
+type iface interface {
+	Foo() *struct{ b bool }
+}
+
+type Int int
+
+func (i Int) Foo() *struct{ b bool } {
+	return &struct{ b bool }{false}
+}
+
+func TestNoRaceForInfiniteLoop(t *testing.T) {
+	var x Int
+	// interface conversion causes nodes to be put on init list
+	for iface(x).Foo().b {
+	}
+}

src/runtime/race/testdata/rwmutex_test.go

@@ -0,0 +1,154 @@
+// Copyright 2012 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 race_test
+
+import (
+	"sync"
+	"testing"
+	"time"
+)
+
+func TestRaceMutexRWMutex(t *testing.T) {
+	var mu1 sync.Mutex
+	var mu2 sync.RWMutex
+	var x int16 = 0
+	_ = x
+	ch := make(chan bool, 2)
+	go func() {
+		mu1.Lock()
+		defer mu1.Unlock()
+		x = 1
+		ch <- true
+	}()
+	go func() {
+		mu2.Lock()
+		x = 2
+		mu2.Unlock()
+		ch <- true
+	}()
+	<-ch
+	<-ch
+}
+
+func TestNoRaceRWMutex(t *testing.T) {
+	var mu sync.RWMutex
+	var x, y int64 = 0, 1
+	_ = y
+	ch := make(chan bool, 2)
+	go func() {
+		mu.Lock()
+		defer mu.Unlock()
+		x = 2
+		ch <- true
+	}()
+	go func() {
+		mu.RLock()
+		y = x
+		mu.RUnlock()
+		ch <- true
+	}()
+	<-ch
+	<-ch
+}
+
+func TestRaceRWMutexMultipleReaders(t *testing.T) {
+	var mu sync.RWMutex
+	var x, y int64 = 0, 1
+	ch := make(chan bool, 4)
+	go func() {
+		mu.Lock()
+		defer mu.Unlock()
+		x = 2
+		ch <- true
+	}()
+	// Use three readers so that no matter what order they're
+	// scheduled in, two will be on the same side of the write
+	// lock above.
+	go func() {
+		mu.RLock()
+		y = x + 1
+		mu.RUnlock()
+		ch <- true
+	}()
+	go func() {
+		mu.RLock()
+		y = x + 2
+		mu.RUnlock()
+		ch <- true
+	}()
+	go func() {
+		mu.RLock()
+		y = x + 3
+		mu.RUnlock()
+		ch <- true
+	}()
+	<-ch
+	<-ch
+	<-ch
+	<-ch
+	_ = y
+}
+
+func TestNoRaceRWMutexMultipleReaders(t *testing.T) {
+	var mu sync.RWMutex
+	x := int64(0)
+	ch := make(chan bool, 4)
+	go func() {
+		mu.Lock()
+		defer mu.Unlock()
+		x = 2
+		ch <- true
+	}()
+	go func() {
+		mu.RLock()
+		y := x + 1
+		_ = y
+		mu.RUnlock()
+		ch <- true
+	}()
+	go func() {
+		mu.RLock()
+		y := x + 2
+		_ = y
+		mu.RUnlock()
+		ch <- true
+	}()
+	go func() {
+		mu.RLock()
+		y := x + 3
+		_ = y
+		mu.RUnlock()
+		ch <- true
+	}()
+	<-ch
+	<-ch
+	<-ch
+	<-ch
+}
+
+func TestNoRaceRWMutexTransitive(t *testing.T) {
+	var mu sync.RWMutex
+	x := int64(0)
+	ch := make(chan bool, 2)
+	go func() {
+		mu.RLock()
+		_ = x
+		mu.RUnlock()
+		ch <- true
+	}()
+	go func() {
+		time.Sleep(1e7)
+		mu.RLock()
+		_ = x
+		mu.RUnlock()
+		ch <- true
+	}()
+	time.Sleep(2e7)
+	mu.Lock()
+	x = 42
+	mu.Unlock()
+	<-ch
+	<-ch
+}

src/runtime/race/testdata/select_test.go

@@ -0,0 +1,293 @@
+// Copyright 2012 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 race_test
+
+import (
+	"runtime"
+	"testing"
+)
+
+func TestNoRaceSelect1(t *testing.T) {
+	var x int
+	_ = x
+	compl := make(chan bool)
+	c := make(chan bool)
+	c1 := make(chan bool)
+
+	go func() {
+		x = 1
+		// At least two channels are needed because
+		// otherwise the compiler optimizes select out.
+		// See comment in runtime/select.go:^func selectgo.
+		select {
+		case c <- true:
+		case c1 <- true:
+		}
+		compl <- true
+	}()
+	select {
+	case <-c:
+	case c1 <- true:
+	}
+	x = 2
+	<-compl
+}
+
+func TestNoRaceSelect2(t *testing.T) {
+	var x int
+	_ = x
+	compl := make(chan bool)
+	c := make(chan bool)
+	c1 := make(chan bool)
+	go func() {
+		select {
+		case <-c:
+		case <-c1:
+		}
+		x = 1
+		compl <- true
+	}()
+	x = 2
+	close(c)
+	runtime.Gosched()
+	<-compl
+}
+
+func TestNoRaceSelect3(t *testing.T) {
+	var x int
+	_ = x
+	compl := make(chan bool)
+	c := make(chan bool, 10)
+	c1 := make(chan bool)
+	go func() {
+		x = 1
+		select {
+		case c <- true:
+		case <-c1:
+		}
+		compl <- true
+	}()
+	<-c
+	x = 2
+	<-compl
+}
+
+func TestNoRaceSelect4(t *testing.T) {
+	type Task struct {
+		f    func()
+		done chan bool
+	}
+
+	queue := make(chan Task)
+	dummy := make(chan bool)
+
+	go func() {
+		for {
+			select {
+			case t := <-queue:
+				t.f()
+				t.done <- true
+			}
+		}
+	}()
+
+	doit := func(f func()) {
+		done := make(chan bool, 1)
+		select {
+		case queue <- Task{f, done}:
+		case <-dummy:
+		}
+		select {
+		case <-done:
+		case <-dummy:
+		}
+	}
+
+	var x int
+	doit(func() {
+		x = 1
+	})
+	_ = x
+}
+
+func TestNoRaceSelect5(t *testing.T) {
+	test := func(sel, needSched bool) {
+		var x int
+		_ = x
+		ch := make(chan bool)
+		c1 := make(chan bool)
+
+		done := make(chan bool, 2)
+		go func() {
+			if needSched {
+				runtime.Gosched()
+			}
+			// println(1)
+			x = 1
+			if sel {
+				select {
+				case ch <- true:
+				case <-c1:
+				}
+			} else {
+				ch <- true
+			}
+			done <- true
+		}()
+
+		go func() {
+			// println(2)
+			if sel {
+				select {
+				case <-ch:
+				case <-c1:
+				}
+			} else {
+				<-ch
+			}
+			x = 1
+			done <- true
+		}()
+		<-done
+		<-done
+	}
+
+	test(true, true)
+	test(true, false)
+	test(false, true)
+	test(false, false)
+}
+
+func TestRaceSelect1(t *testing.T) {
+	var x int
+	_ = x
+	compl := make(chan bool, 2)
+	c := make(chan bool)
+	c1 := make(chan bool)
+
+	go func() {
+		<-c
+		<-c
+	}()
+	f := func() {
+		select {
+		case c <- true:
+		case c1 <- true:
+		}
+		x = 1
+		compl <- true
+	}
+	go f()
+	go f()
+	<-compl
+	<-compl
+}
+
+func TestRaceSelect2(t *testing.T) {
+	var x int
+	_ = x
+	compl := make(chan bool)
+	c := make(chan bool)
+	c1 := make(chan bool)
+	go func() {
+		x = 1
+		select {
+		case <-c:
+		case <-c1:
+		}
+		compl <- true
+	}()
+	close(c)
+	x = 2
+	<-compl
+}
+
+func TestRaceSelect3(t *testing.T) {
+	var x int
+	_ = x
+	compl := make(chan bool)
+	c := make(chan bool)
+	c1 := make(chan bool)
+	go func() {
+		x = 1
+		select {
+		case c <- true:
+		case c1 <- true:
+		}
+		compl <- true
+	}()
+	x = 2
+	select {
+	case <-c:
+	}
+	<-compl
+}
+
+func TestRaceSelect4(t *testing.T) {
+	done := make(chan bool, 1)
+	var x int
+	go func() {
+		select {
+		default:
+			x = 2
+		}
+		done <- true
+	}()
+	_ = x
+	<-done
+}
+
+// The idea behind this test:
+// there are two variables, access to one
+// of them is synchronized, access to the other
+// is not.
+// Select must (unconditionally) choose the non-synchronized variable
+// thus causing exactly one race.
+// Currently this test doesn't look like it accomplishes
+// this goal.
+func TestRaceSelect5(t *testing.T) {
+	done := make(chan bool, 1)
+	c1 := make(chan bool, 1)
+	c2 := make(chan bool)
+	var x, y int
+	go func() {
+		select {
+		case c1 <- true:
+			x = 1
+		case c2 <- true:
+			y = 1
+		}
+		done <- true
+	}()
+	_ = x
+	_ = y
+	<-done
+}
+
+// select statements may introduce
+// flakiness: whether this test contains
+// a race depends on the scheduling
+// (some may argue that the code contains
+// this race by definition)
+/*
+func TestFlakyDefault(t *testing.T) {
+	var x int
+	c := make(chan bool, 1)
+	done := make(chan bool, 1)
+	go func() {
+		select {
+		case <-c:
+			x = 2
+		default:
+			x = 3
+		}
+		done <- true
+	}()
+	x = 1
+	c <- true
+	_ = x
+	<-done
+}
+*/

src/runtime/race/testdata/slice_test.go

@@ -0,0 +1,608 @@
+// Copyright 2012 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 race_test
+
+import (
+	"sync"
+	"testing"
+)
+
+func TestRaceSliceRW(t *testing.T) {
+	ch := make(chan bool, 1)
+	a := make([]int, 2)
+	go func() {
+		a[1] = 1
+		ch <- true
+	}()
+	_ = a[1]
+	<-ch
+}
+
+func TestNoRaceSliceRW(t *testing.T) {
+	ch := make(chan bool, 1)
+	a := make([]int, 2)
+	go func() {
+		a[0] = 1
+		ch <- true
+	}()
+	_ = a[1]
+	<-ch
+}
+
+func TestRaceSliceWW(t *testing.T) {
+	a := make([]int, 10)
+	ch := make(chan bool, 1)
+	go func() {
+		a[1] = 1
+		ch <- true
+	}()
+	a[1] = 2
+	<-ch
+}
+
+func TestNoRaceArrayWW(t *testing.T) {
+	var a [5]int
+	ch := make(chan bool, 1)
+	go func() {
+		a[0] = 1
+		ch <- true
+	}()
+	a[1] = 2
+	<-ch
+}
+
+func TestRaceArrayWW(t *testing.T) {
+	var a [5]int
+	ch := make(chan bool, 1)
+	go func() {
+		a[1] = 1
+		ch <- true
+	}()
+	a[1] = 2
+	<-ch
+}
+
+func TestNoRaceSliceWriteLen(t *testing.T) {
+	ch := make(chan bool, 1)
+	a := make([]bool, 1)
+	go func() {
+		a[0] = true
+		ch <- true
+	}()
+	_ = len(a)
+	<-ch
+}
+
+func TestNoRaceSliceWriteCap(t *testing.T) {
+	ch := make(chan bool, 1)
+	a := make([]uint64, 100)
+	go func() {
+		a[50] = 123
+		ch <- true
+	}()
+	_ = cap(a)
+	<-ch
+}
+
+func TestRaceSliceCopyRead(t *testing.T) {
+	ch := make(chan bool, 1)
+	a := make([]int, 10)
+	b := make([]int, 10)
+	go func() {
+		_ = a[5]
+		ch <- true
+	}()
+	copy(a, b)
+	<-ch
+}
+
+func TestNoRaceSliceWriteCopy(t *testing.T) {
+	ch := make(chan bool, 1)
+	a := make([]int, 10)
+	b := make([]int, 10)
+	go func() {
+		a[5] = 1
+		ch <- true
+	}()
+	copy(a[:5], b[:5])
+	<-ch
+}
+
+func TestRaceSliceCopyWrite2(t *testing.T) {
+	ch := make(chan bool, 1)
+	a := make([]int, 10)
+	b := make([]int, 10)
+	go func() {
+		b[5] = 1
+		ch <- true
+	}()
+	copy(a, b)
+	<-ch
+}
+
+func TestRaceSliceCopyWrite3(t *testing.T) {
+	ch := make(chan bool, 1)
+	a := make([]byte, 10)
+	go func() {
+		a[7] = 1
+		ch <- true
+	}()
+	copy(a, "qwertyqwerty")
+	<-ch
+}
+
+func TestNoRaceSliceCopyRead(t *testing.T) {
+	ch := make(chan bool, 1)
+	a := make([]int, 10)
+	b := make([]int, 10)
+	go func() {
+		_ = b[5]
+		ch <- true
+	}()
+	copy(a, b)
+	<-ch
+}
+
+func TestRacePointerSliceCopyRead(t *testing.T) {
+	ch := make(chan bool, 1)
+	a := make([]*int, 10)
+	b := make([]*int, 10)
+	go func() {
+		_ = a[5]
+		ch <- true
+	}()
+	copy(a, b)
+	<-ch
+}
+
+func TestNoRacePointerSliceWriteCopy(t *testing.T) {
+	ch := make(chan bool, 1)
+	a := make([]*int, 10)
+	b := make([]*int, 10)
+	go func() {
+		a[5] = new(int)
+		ch <- true
+	}()
+	copy(a[:5], b[:5])
+	<-ch
+}
+
+func TestRacePointerSliceCopyWrite2(t *testing.T) {
+	ch := make(chan bool, 1)
+	a := make([]*int, 10)
+	b := make([]*int, 10)
+	go func() {
+		b[5] = new(int)
+		ch <- true
+	}()
+	copy(a, b)
+	<-ch
+}
+
+func TestNoRacePointerSliceCopyRead(t *testing.T) {
+	ch := make(chan bool, 1)
+	a := make([]*int, 10)
+	b := make([]*int, 10)
+	go func() {
+		_ = b[5]
+		ch <- true
+	}()
+	copy(a, b)
+	<-ch
+}
+
+func TestNoRaceSliceWriteSlice2(t *testing.T) {
+	ch := make(chan bool, 1)
+	a := make([]float64, 10)
+	go func() {
+		a[2] = 1.0
+		ch <- true
+	}()
+	_ = a[0:5]
+	<-ch
+}
+
+func TestRaceSliceWriteSlice(t *testing.T) {
+	ch := make(chan bool, 1)
+	a := make([]float64, 10)
+	go func() {
+		a[2] = 1.0
+		ch <- true
+	}()
+	a = a[5:10]
+	<-ch
+}
+
+func TestNoRaceSliceWriteSlice(t *testing.T) {
+	ch := make(chan bool, 1)
+	a := make([]float64, 10)
+	go func() {
+		a[2] = 1.0
+		ch <- true
+	}()
+	_ = a[5:10]
+	<-ch
+}
+
+func TestNoRaceSliceLenCap(t *testing.T) {
+	ch := make(chan bool, 1)
+	a := make([]struct{}, 10)
+	go func() {
+		_ = len(a)
+		ch <- true
+	}()
+	_ = cap(a)
+	<-ch
+}
+
+func TestNoRaceStructSlicesRangeWrite(t *testing.T) {
+	type Str struct {
+		a []int
+		b []int
+	}
+	ch := make(chan bool, 1)
+	var s Str
+	s.a = make([]int, 10)
+	s.b = make([]int, 10)
+	go func() {
+		for range s.a {
+		}
+		ch <- true
+	}()
+	s.b[5] = 5
+	<-ch
+}
+
+func TestRaceSliceDifferent(t *testing.T) {
+	c := make(chan bool, 1)
+	s := make([]int, 10)
+	s2 := s
+	go func() {
+		s[3] = 3
+		c <- true
+	}()
+	// false negative because s2 is PAUTO w/o PHEAP
+	// so we do not instrument it
+	s2[3] = 3
+	<-c
+}
+
+func TestRaceSliceRangeWrite(t *testing.T) {
+	c := make(chan bool, 1)
+	s := make([]int, 10)
+	go func() {
+		s[3] = 3
+		c <- true
+	}()
+	for _, v := range s {
+		_ = v
+	}
+	<-c
+}
+
+func TestNoRaceSliceRangeWrite(t *testing.T) {
+	c := make(chan bool, 1)
+	s := make([]int, 10)
+	go func() {
+		s[3] = 3
+		c <- true
+	}()
+	for range s {
+	}
+	<-c
+}
+
+func TestRaceSliceRangeAppend(t *testing.T) {
+	c := make(chan bool, 1)
+	s := make([]int, 10)
+	go func() {
+		s = append(s, 3)
+		c <- true
+	}()
+	for range s {
+	}
+	<-c
+}
+
+func TestNoRaceSliceRangeAppend(t *testing.T) {
+	c := make(chan bool, 1)
+	s := make([]int, 10)
+	go func() {
+		_ = append(s, 3)
+		c <- true
+	}()
+	for range s {
+	}
+	<-c
+}
+
+func TestRaceSliceVarWrite(t *testing.T) {
+	c := make(chan bool, 1)
+	s := make([]int, 10)
+	go func() {
+		s[3] = 3
+		c <- true
+	}()
+	s = make([]int, 20)
+	<-c
+}
+
+func TestRaceSliceVarRead(t *testing.T) {
+	c := make(chan bool, 1)
+	s := make([]int, 10)
+	go func() {
+		_ = s[3]
+		c <- true
+	}()
+	s = make([]int, 20)
+	<-c
+}
+
+func TestRaceSliceVarRange(t *testing.T) {
+	c := make(chan bool, 1)
+	s := make([]int, 10)
+	go func() {
+		for range s {
+		}
+		c <- true
+	}()
+	s = make([]int, 20)
+	<-c
+}
+
+func TestRaceSliceVarAppend(t *testing.T) {
+	c := make(chan bool, 1)
+	s := make([]int, 10)
+	go func() {
+		_ = append(s, 10)
+		c <- true
+	}()
+	s = make([]int, 20)
+	<-c
+}
+
+func TestRaceSliceVarCopy(t *testing.T) {
+	c := make(chan bool, 1)
+	s := make([]int, 10)
+	go func() {
+		s2 := make([]int, 10)
+		copy(s, s2)
+		c <- true
+	}()
+	s = make([]int, 20)
+	<-c
+}
+
+func TestRaceSliceVarCopy2(t *testing.T) {
+	c := make(chan bool, 1)
+	s := make([]int, 10)
+	go func() {
+		s2 := make([]int, 10)
+		copy(s2, s)
+		c <- true
+	}()
+	s = make([]int, 20)
+	<-c
+}
+
+func TestRaceSliceAppend(t *testing.T) {
+	c := make(chan bool, 1)
+	s := make([]int, 10, 20)
+	go func() {
+		_ = append(s, 1)
+		c <- true
+	}()
+	_ = append(s, 2)
+	<-c
+}
+
+func TestRaceSliceAppendWrite(t *testing.T) {
+	c := make(chan bool, 1)
+	s := make([]int, 10)
+	go func() {
+		_ = append(s, 1)
+		c <- true
+	}()
+	s[0] = 42
+	<-c
+}
+
+func TestRaceSliceAppendSlice(t *testing.T) {
+	c := make(chan bool, 1)
+	s := make([]int, 10)
+	go func() {
+		s2 := make([]int, 10)
+		_ = append(s, s2...)
+		c <- true
+	}()
+	s[0] = 42
+	<-c
+}
+
+func TestRaceSliceAppendSlice2(t *testing.T) {
+	c := make(chan bool, 1)
+	s := make([]int, 10)
+	s2foobar := make([]int, 10)
+	go func() {
+		_ = append(s, s2foobar...)
+		c <- true
+	}()
+	s2foobar[5] = 42
+	<-c
+}
+
+func TestRaceSliceAppendString(t *testing.T) {
+	c := make(chan bool, 1)
+	s := make([]byte, 10)
+	go func() {
+		_ = append(s, "qwerty"...)
+		c <- true
+	}()
+	s[0] = 42
+	<-c
+}
+
+func TestRacePointerSliceAppend(t *testing.T) {
+	c := make(chan bool, 1)
+	s := make([]*int, 10, 20)
+	go func() {
+		_ = append(s, new(int))
+		c <- true
+	}()
+	_ = append(s, new(int))
+	<-c
+}
+
+func TestRacePointerSliceAppendWrite(t *testing.T) {
+	c := make(chan bool, 1)
+	s := make([]*int, 10)
+	go func() {
+		_ = append(s, new(int))
+		c <- true
+	}()
+	s[0] = new(int)
+	<-c
+}
+
+func TestRacePointerSliceAppendSlice(t *testing.T) {
+	c := make(chan bool, 1)
+	s := make([]*int, 10)
+	go func() {
+		s2 := make([]*int, 10)
+		_ = append(s, s2...)
+		c <- true
+	}()
+	s[0] = new(int)
+	<-c
+}
+
+func TestRacePointerSliceAppendSlice2(t *testing.T) {
+	c := make(chan bool, 1)
+	s := make([]*int, 10)
+	s2foobar := make([]*int, 10)
+	go func() {
+		_ = append(s, s2foobar...)
+		c <- true
+	}()
+	println("WRITE:", &s2foobar[5])
+	s2foobar[5] = nil
+	<-c
+}
+
+func TestNoRaceSliceIndexAccess(t *testing.T) {
+	c := make(chan bool, 1)
+	s := make([]int, 10)
+	v := 0
+	go func() {
+		_ = v
+		c <- true
+	}()
+	s[v] = 1
+	<-c
+}
+
+func TestNoRaceSliceIndexAccess2(t *testing.T) {
+	c := make(chan bool, 1)
+	s := make([]int, 10)
+	v := 0
+	go func() {
+		_ = v
+		c <- true
+	}()
+	_ = s[v]
+	<-c
+}
+
+func TestRaceSliceIndexAccess(t *testing.T) {
+	c := make(chan bool, 1)
+	s := make([]int, 10)
+	v := 0
+	go func() {
+		v = 1
+		c <- true
+	}()
+	s[v] = 1
+	<-c
+}
+
+func TestRaceSliceIndexAccess2(t *testing.T) {
+	c := make(chan bool, 1)
+	s := make([]int, 10)
+	v := 0
+	go func() {
+		v = 1
+		c <- true
+	}()
+	_ = s[v]
+	<-c
+}
+
+func TestRaceSliceByteToString(t *testing.T) {
+	c := make(chan string)
+	s := make([]byte, 10)
+	go func() {
+		c <- string(s)
+	}()
+	s[0] = 42
+	<-c
+}
+
+func TestRaceSliceRuneToString(t *testing.T) {
+	c := make(chan string)
+	s := make([]rune, 10)
+	go func() {
+		c <- string(s)
+	}()
+	s[9] = 42
+	<-c
+}
+
+func TestRaceConcatString(t *testing.T) {
+	s := "hello"
+	c := make(chan string, 1)
+	go func() {
+		c <- s + " world"
+	}()
+	s = "world"
+	<-c
+}
+
+func TestRaceCompareString(t *testing.T) {
+	s1 := "hello"
+	s2 := "world"
+	c := make(chan bool, 1)
+	go func() {
+		c <- s1 == s2
+	}()
+	s1 = s2
+	<-c
+}
+
+func TestRaceSlice3(t *testing.T) {
+	done := make(chan bool)
+	x := make([]int, 10)
+	i := 2
+	go func() {
+		i = 3
+		done <- true
+	}()
+	_ = x[:1:i]
+	<-done
+}
+
+var saved string
+
+func TestRaceSlice4(t *testing.T) {
+	// See issue 36794.
+	data := []byte("hello there")
+	var wg sync.WaitGroup
+	wg.Add(1)
+	go func() {
+		_ = string(data)
+		wg.Done()
+	}()
+	copy(data, data[2:])
+	wg.Wait()
+}

src/runtime/race/testdata/sync_test.go

@@ -0,0 +1,202 @@
+// Copyright 2011 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 race_test
+
+import (
+	"sync"
+	"testing"
+	"time"
+)
+
+func TestNoRaceCond(t *testing.T) {
+	x := 0
+	_ = x
+	condition := 0
+	var mu sync.Mutex
+	cond := sync.NewCond(&mu)
+	go func() {
+		x = 1
+		mu.Lock()
+		condition = 1
+		cond.Signal()
+		mu.Unlock()
+	}()
+	mu.Lock()
+	for condition != 1 {
+		cond.Wait()
+	}
+	mu.Unlock()
+	x = 2
+}
+
+func TestRaceCond(t *testing.T) {
+	done := make(chan bool)
+	var mu sync.Mutex
+	cond := sync.NewCond(&mu)
+	x := 0
+	_ = x
+	condition := 0
+	go func() {
+		time.Sleep(10 * time.Millisecond) // Enter cond.Wait loop
+		x = 1
+		mu.Lock()
+		condition = 1
+		cond.Signal()
+		mu.Unlock()
+		time.Sleep(10 * time.Millisecond) // Exit cond.Wait loop
+		mu.Lock()
+		x = 3
+		mu.Unlock()
+		done <- true
+	}()
+	mu.Lock()
+	for condition != 1 {
+		cond.Wait()
+	}
+	mu.Unlock()
+	x = 2
+	<-done
+}
+
+// We do not currently automatically
+// parse this test. It is intended that the creation
+// stack is observed manually not to contain
+// off-by-one errors
+func TestRaceAnnounceThreads(t *testing.T) {
+	const N = 7
+	allDone := make(chan bool, N)
+
+	var x int
+	_ = x
+
+	var f, g, h func()
+	f = func() {
+		x = 1
+		go g()
+		go func() {
+			x = 1
+			allDone <- true
+		}()
+		x = 2
+		allDone <- true
+	}
+
+	g = func() {
+		for i := 0; i < 2; i++ {
+			go func() {
+				x = 1
+				allDone <- true
+			}()
+			allDone <- true
+		}
+	}
+
+	h = func() {
+		x = 1
+		x = 2
+		go f()
+		allDone <- true
+	}
+
+	go h()
+
+	for i := 0; i < N; i++ {
+		<-allDone
+	}
+}
+
+func TestNoRaceAfterFunc1(t *testing.T) {
+	i := 2
+	c := make(chan bool)
+	var f func()
+	f = func() {
+		i--
+		if i >= 0 {
+			time.AfterFunc(0, f)
+		} else {
+			c <- true
+		}
+	}
+
+	time.AfterFunc(0, f)
+	<-c
+}
+
+func TestNoRaceAfterFunc2(t *testing.T) {
+	var x int
+	_ = x
+	timer := time.AfterFunc(10, func() {
+		x = 1
+	})
+	defer timer.Stop()
+}
+
+func TestNoRaceAfterFunc3(t *testing.T) {
+	c := make(chan bool, 1)
+	x := 0
+	_ = x
+	time.AfterFunc(1e7, func() {
+		x = 1
+		c <- true
+	})
+	<-c
+}
+
+func TestRaceAfterFunc3(t *testing.T) {
+	c := make(chan bool, 2)
+	x := 0
+	_ = x
+	time.AfterFunc(1e7, func() {
+		x = 1
+		c <- true
+	})
+	time.AfterFunc(2e7, func() {
+		x = 2
+		c <- true
+	})
+	<-c
+	<-c
+}
+
+// This test's output is intended to be
+// observed manually. One should check
+// that goroutine creation stack is
+// comprehensible.
+func TestRaceGoroutineCreationStack(t *testing.T) {
+	var x int
+	_ = x
+	var ch = make(chan bool, 1)
+
+	f1 := func() {
+		x = 1
+		ch <- true
+	}
+	f2 := func() { go f1() }
+	f3 := func() { go f2() }
+	f4 := func() { go f3() }
+
+	go f4()
+	x = 2
+	<-ch
+}
+
+// A nil pointer in a mutex method call should not
+// corrupt the race detector state.
+// Used to hang indefinitely.
+func TestNoRaceNilMutexCrash(t *testing.T) {
+	var mutex sync.Mutex
+	panics := 0
+	defer func() {
+		if x := recover(); x != nil {
+			mutex.Lock()
+			panics++
+			mutex.Unlock()
+		} else {
+			panic("no panic")
+		}
+	}()
+	var othermutex *sync.RWMutex
+	othermutex.RLock()
+}

src/runtime/race/testdata/time_test.go

@@ -0,0 +1,116 @@
+// Copyright 2011 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 race_test
+
+import (
+	"testing"
+	"time"
+)
+
+func TestNoRaceAfterFunc(_ *testing.T) {
+	v := 0
+	_ = v
+	c := make(chan int)
+	f := func() {
+		v = 1
+		c <- 0
+	}
+	v = 2
+	time.AfterFunc(1, f)
+	<-c
+	v = 3
+}
+
+func TestNoRaceAfterFuncReset(_ *testing.T) {
+	v := 0
+	_ = v
+	c := make(chan int)
+	f := func() {
+		v = 1
+		c <- 0
+	}
+	t := time.AfterFunc(time.Hour, f)
+	t.Stop()
+	v = 2
+	t.Reset(1)
+	<-c
+	v = 3
+}
+
+func TestNoRaceTimer(_ *testing.T) {
+	v := 0
+	_ = v
+	c := make(chan int)
+	f := func() {
+		v = 1
+		c <- 0
+	}
+	v = 2
+	t := time.NewTimer(1)
+	go func() {
+		<-t.C
+		f()
+	}()
+	<-c
+	v = 3
+}
+
+func TestNoRaceTimerReset(_ *testing.T) {
+	v := 0
+	_ = v
+	c := make(chan int)
+	f := func() {
+		v = 1
+		c <- 0
+	}
+	t := time.NewTimer(time.Hour)
+	go func() {
+		<-t.C
+		f()
+	}()
+	t.Stop()
+	v = 2
+	t.Reset(1)
+	<-c
+	v = 3
+}
+
+func TestNoRaceTicker(_ *testing.T) {
+	v := 0
+	_ = v
+	c := make(chan int)
+	f := func() {
+		v = 1
+		c <- 0
+	}
+	v = 2
+	t := time.NewTicker(1)
+	go func() {
+		<-t.C
+		f()
+	}()
+	<-c
+	v = 3
+}
+
+func TestNoRaceTickerReset(_ *testing.T) {
+	v := 0
+	_ = v
+	c := make(chan int)
+	f := func() {
+		v = 1
+		c <- 0
+	}
+	t := time.NewTicker(time.Hour)
+	go func() {
+		<-t.C
+		f()
+	}()
+	t.Stop()
+	v = 2
+	t.Reset(1)
+	<-c
+	v = 3
+}

src/runtime/race/testdata/waitgroup_test.go

@@ -0,0 +1,360 @@
+// Copyright 2012 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 race_test
+
+import (
+	"runtime"
+	"sync"
+	"testing"
+	"time"
+)
+
+func TestNoRaceWaitGroup(t *testing.T) {
+	var x int
+	_ = x
+	var wg sync.WaitGroup
+	n := 1
+	for i := 0; i < n; i++ {
+		wg.Add(1)
+		j := i
+		go func() {
+			x = j
+			wg.Done()
+		}()
+	}
+	wg.Wait()
+}
+
+func TestRaceWaitGroup(t *testing.T) {
+	var x int
+	_ = x
+	var wg sync.WaitGroup
+	n := 2
+	for i := 0; i < n; i++ {
+		wg.Add(1)
+		j := i
+		go func() {
+			x = j
+			wg.Done()
+		}()
+	}
+	wg.Wait()
+}
+
+func TestNoRaceWaitGroup2(t *testing.T) {
+	var x int
+	_ = x
+	var wg sync.WaitGroup
+	wg.Add(1)
+	go func() {
+		x = 1
+		wg.Done()
+	}()
+	wg.Wait()
+	x = 2
+}
+
+// incrementing counter in Add and locking wg's mutex
+func TestRaceWaitGroupAsMutex(t *testing.T) {
+	var x int
+	_ = x
+	var wg sync.WaitGroup
+	c := make(chan bool, 2)
+	go func() {
+		wg.Wait()
+		time.Sleep(100 * time.Millisecond)
+		wg.Add(+1)
+		x = 1
+		wg.Add(-1)
+		c <- true
+	}()
+	go func() {
+		wg.Wait()
+		time.Sleep(100 * time.Millisecond)
+		wg.Add(+1)
+		x = 2
+		wg.Add(-1)
+		c <- true
+	}()
+	<-c
+	<-c
+}
+
+// Incorrect usage: Add is too late.
+func TestRaceWaitGroupWrongWait(t *testing.T) {
+	c := make(chan bool, 2)
+	var x int
+	_ = x
+	var wg sync.WaitGroup
+	go func() {
+		wg.Add(1)
+		runtime.Gosched()
+		x = 1
+		wg.Done()
+		c <- true
+	}()
+	go func() {
+		wg.Add(1)
+		runtime.Gosched()
+		x = 2
+		wg.Done()
+		c <- true
+	}()
+	wg.Wait()
+	<-c
+	<-c
+}
+
+func TestRaceWaitGroupWrongAdd(t *testing.T) {
+	c := make(chan bool, 2)
+	var wg sync.WaitGroup
+	go func() {
+		wg.Add(1)
+		time.Sleep(100 * time.Millisecond)
+		wg.Done()
+		c <- true
+	}()
+	go func() {
+		wg.Add(1)
+		time.Sleep(100 * time.Millisecond)
+		wg.Done()
+		c <- true
+	}()
+	time.Sleep(50 * time.Millisecond)
+	wg.Wait()
+	<-c
+	<-c
+}
+
+func TestNoRaceWaitGroupMultipleWait(t *testing.T) {
+	c := make(chan bool, 2)
+	var wg sync.WaitGroup
+	go func() {
+		wg.Wait()
+		c <- true
+	}()
+	go func() {
+		wg.Wait()
+		c <- true
+	}()
+	wg.Wait()
+	<-c
+	<-c
+}
+
+func TestNoRaceWaitGroupMultipleWait2(t *testing.T) {
+	c := make(chan bool, 2)
+	var wg sync.WaitGroup
+	wg.Add(2)
+	go func() {
+		wg.Done()
+		wg.Wait()
+		c <- true
+	}()
+	go func() {
+		wg.Done()
+		wg.Wait()
+		c <- true
+	}()
+	wg.Wait()
+	<-c
+	<-c
+}
+
+func TestNoRaceWaitGroupMultipleWait3(t *testing.T) {
+	const P = 3
+	var data [P]int
+	done := make(chan bool, P)
+	var wg sync.WaitGroup
+	wg.Add(P)
+	for p := 0; p < P; p++ {
+		go func(p int) {
+			data[p] = 42
+			wg.Done()
+		}(p)
+	}
+	for p := 0; p < P; p++ {
+		go func() {
+			wg.Wait()
+			for p1 := 0; p1 < P; p1++ {
+				_ = data[p1]
+			}
+			done <- true
+		}()
+	}
+	for p := 0; p < P; p++ {
+		<-done
+	}
+}
+
+// Correct usage but still a race
+func TestRaceWaitGroup2(t *testing.T) {
+	var x int
+	_ = x
+	var wg sync.WaitGroup
+	wg.Add(2)
+	go func() {
+		x = 1
+		wg.Done()
+	}()
+	go func() {
+		x = 2
+		wg.Done()
+	}()
+	wg.Wait()
+}
+
+func TestNoRaceWaitGroupPanicRecover(t *testing.T) {
+	var x int
+	_ = x
+	var wg sync.WaitGroup
+	defer func() {
+		err := recover()
+		if err != "sync: negative WaitGroup counter" {
+			t.Fatalf("Unexpected panic: %#v", err)
+		}
+		x = 2
+	}()
+	x = 1
+	wg.Add(-1)
+}
+
+// TODO: this is actually a panic-synchronization test, not a
+// WaitGroup test. Move it to another *_test file
+// Is it possible to get a race by synchronization via panic?
+func TestNoRaceWaitGroupPanicRecover2(t *testing.T) {
+	var x int
+	_ = x
+	var wg sync.WaitGroup
+	ch := make(chan bool, 1)
+	var f func() = func() {
+		x = 2
+		ch <- true
+	}
+	go func() {
+		defer func() {
+			err := recover()
+			if err != "sync: negative WaitGroup counter" {
+			}
+			go f()
+		}()
+		x = 1
+		wg.Add(-1)
+	}()
+
+	<-ch
+}
+
+func TestNoRaceWaitGroupTransitive(t *testing.T) {
+	x, y := 0, 0
+	var wg sync.WaitGroup
+	wg.Add(2)
+	go func() {
+		x = 42
+		wg.Done()
+	}()
+	go func() {
+		time.Sleep(1e7)
+		y = 42
+		wg.Done()
+	}()
+	wg.Wait()
+	_ = x
+	_ = y
+}
+
+func TestNoRaceWaitGroupReuse(t *testing.T) {
+	const P = 3
+	var data [P]int
+	var wg sync.WaitGroup
+	for try := 0; try < 3; try++ {
+		wg.Add(P)
+		for p := 0; p < P; p++ {
+			go func(p int) {
+				data[p]++
+				wg.Done()
+			}(p)
+		}
+		wg.Wait()
+		for p := 0; p < P; p++ {
+			data[p]++
+		}
+	}
+}
+
+func TestNoRaceWaitGroupReuse2(t *testing.T) {
+	const P = 3
+	var data [P]int
+	var wg sync.WaitGroup
+	for try := 0; try < 3; try++ {
+		wg.Add(P)
+		for p := 0; p < P; p++ {
+			go func(p int) {
+				data[p]++
+				wg.Done()
+			}(p)
+		}
+		done := make(chan bool)
+		go func() {
+			wg.Wait()
+			for p := 0; p < P; p++ {
+				data[p]++
+			}
+			done <- true
+		}()
+		wg.Wait()
+		<-done
+		for p := 0; p < P; p++ {
+			data[p]++
+		}
+	}
+}
+
+func TestRaceWaitGroupReuse(t *testing.T) {
+	const P = 3
+	const T = 3
+	done := make(chan bool, T)
+	var wg sync.WaitGroup
+	for try := 0; try < T; try++ {
+		var data [P]int
+		wg.Add(P)
+		for p := 0; p < P; p++ {
+			go func(p int) {
+				time.Sleep(50 * time.Millisecond)
+				data[p]++
+				wg.Done()
+			}(p)
+		}
+		go func() {
+			wg.Wait()
+			for p := 0; p < P; p++ {
+				data[p]++
+			}
+			done <- true
+		}()
+		time.Sleep(100 * time.Millisecond)
+		wg.Wait()
+	}
+	for try := 0; try < T; try++ {
+		<-done
+	}
+}
+
+func TestNoRaceWaitGroupConcurrentAdd(t *testing.T) {
+	const P = 4
+	waiting := make(chan bool, P)
+	var wg sync.WaitGroup
+	for p := 0; p < P; p++ {
+		go func() {
+			wg.Add(1)
+			waiting <- true
+			wg.Done()
+		}()
+	}
+	for p := 0; p < P; p++ {
+		<-waiting
+	}
+	wg.Wait()
+}

src/runtime/race/timer_test.go

@@ -0,0 +1,33 @@
+// Copyright 2019 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.
+
+//go:build race
+
+package race_test
+
+import (
+	"sync"
+	"testing"
+	"time"
+)
+
+func TestTimers(t *testing.T) {
+	const goroutines = 8
+	var wg sync.WaitGroup
+	wg.Add(goroutines)
+	var mu sync.Mutex
+	for i := 0; i < goroutines; i++ {
+		go func() {
+			defer wg.Done()
+			ticker := time.NewTicker(1)
+			defer ticker.Stop()
+			for c := 0; c < 1000; c++ {
+				<-ticker.C
+				mu.Lock()
+				mu.Unlock()
+			}
+		}()
+	}
+	wg.Wait()
+}