runtime/race: don't crash on invalid PCs

Currently raceSymbolizeCode uses funcline, which is internal runtime
function which crashes on incorrect PCs. Use FileLine instead,
it is public and does not crash on invalid data.

Note: FileLine returns "?" file on failure. That string is not NUL-terminated,
so we need to additionally check what FileLine returns.

Fixes #17190

Change-Id: Ic6fbd4f0e68ddd52e9b2dd25e625b50adcb69a98
Reviewed-on: https://go-review.googlesource.com/29714
Run-TryBot: Dmitry Vyukov <dvyukov@google.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

src/runtime/race.go

@@ -91,23 +91,23 @@ func racecallback(cmd uintptr, ctx unsafe.Pointer) {
 }
 
 func raceSymbolizeCode(ctx *symbolizeCodeContext) {
-	f := findfunc(ctx.pc)
-	if f == nil {
+	f := FuncForPC(ctx.pc)
+	if f != nil {
+		file, line := f.FileLine(ctx.pc)
+		if line != 0 {
+			ctx.fn = cfuncname(f.raw())
+			ctx.line = uintptr(line)
+			ctx.file = &bytes(file)[0] // assume NUL-terminated
+			ctx.off = ctx.pc - f.Entry()
+			ctx.res = 1
+			return
+		}
+	}
 	ctx.fn = &qq[0]
 	ctx.file = &dash[0]
 	ctx.line = 0
 	ctx.off = ctx.pc
 	ctx.res = 1
-		return
-	}
-
-	ctx.fn = cfuncname(f)
-	file, line := funcline(f, ctx.pc)
-	ctx.line = uintptr(line)
-	ctx.file = &bytes(file)[0] // assume NUL-terminated
-	ctx.off = ctx.pc - f.entry
-	ctx.res = 1
-	return
 }
 
 type symbolizeDataContext struct {

src/runtime/race/output_test.go

@@ -13,12 +13,17 @@ import (
 	"os/exec"
 	"path/filepath"
 	"regexp"
+	"runtime"
 	"strings"
 	"testing"
 )
 
 func TestOutput(t *testing.T) {
 	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, err := ioutil.TempDir("", "go-build")
 		if err != nil {
 			t.Fatalf("failed to create temp directory: %v", err)
@@ -67,11 +72,12 @@ func TestOutput(t *testing.T) {
 var tests = []struct {
 	name   string
 	run    string
+	goos   string
 	gorace string
 	source string
 	re     string
 }{
-	{"simple", "run", "atexit_sleep_ms=0", `
+	{"simple", "run", "", "atexit_sleep_ms=0", `
 package main
 import "time"
 func main() {
@@ -116,7 +122,7 @@ Found 1 data race\(s\)
 exit status 66
 `},
 
-	{"exitcode", "run", "atexit_sleep_ms=0 exitcode=13", `
+	{"exitcode", "run", "", "atexit_sleep_ms=0 exitcode=13", `
 package main
 func main() {
 	done := make(chan bool)
@@ -130,7 +136,7 @@ func main() {
 }
 `, `exit status 13`},
 
-	{"strip_path_prefix", "run", "atexit_sleep_ms=0 strip_path_prefix=/main.", `
+	{"strip_path_prefix", "run", "", "atexit_sleep_ms=0 strip_path_prefix=/main.", `
 package main
 func main() {
 	done := make(chan bool)
@@ -146,7 +152,7 @@ func main() {
       go:7 \+0x[0-9,a-f]+
 `},
 
-	{"halt_on_error", "run", "atexit_sleep_ms=0 halt_on_error=1", `
+	{"halt_on_error", "run", "", "atexit_sleep_ms=0 halt_on_error=1", `
 package main
 func main() {
 	done := make(chan bool)
@@ -163,7 +169,7 @@ func main() {
 exit status 66
 `},
 
-	{"test_fails_on_race", "test", "atexit_sleep_ms=0", `
+	{"test_fails_on_race", "test", "", "atexit_sleep_ms=0", `
 package main_test
 import "testing"
 func TestFail(t *testing.T) {
@@ -182,7 +188,7 @@ PASS
 Found 1 data race\(s\)
 FAIL`},
 
-	{"slicebytetostring_pc", "run", "atexit_sleep_ms=0", `
+	{"slicebytetostring_pc", "run", "", "atexit_sleep_ms=0", `
 package main
 func main() {
 	done := make(chan string)
@@ -198,4 +204,57 @@ func main() {
       .*/runtime/string\.go:.*
   main\.main\.func1\(\)
       .*/main.go:7`},
+
+	// Test for http://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"
+
+import "time"
+
+var racy int
+
+//export goCallback
+func goCallback() {
+	racy++
+}
+
+func main() {
+	var c C.cb
+	C.startThread(&c)
+	time.Sleep(time.Second)
+	racy++
+}
+`, `==================
+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]+
+  main._cgoexpwrap_[0-9a-z]+_goCallback\(\)
+      .*/_cgo_gotypes\.go:[0-9]+ \+0x[0-9,a-f]+
+
+Goroutine [0-9] \(running\) created at:
+  runtime\.newextram\(\)
+      .*/runtime/proc.go:[0-9]+ \+0x[0-9,a-f]+
+==================`},
 }