runtime: fix data race in findfunc()
The data race can lead to reads of partially
initialized concurrently mutated symbol data.
The change also adds a simple sanity test
for Caller() and FuncForPC().
R=rsc
CC=golang-dev
https://golang.org/cl/4817058
diff --git a/src/pkg/runtime/symtab_test.go b/src/pkg/runtime/symtab_test.go
new file mode 100644
index 0000000..bd9fe18
--- /dev/null
+++ b/src/pkg/runtime/symtab_test.go
@@ -0,0 +1,47 @@
+// Copyright 2009 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 runtime_test
+
+import (
+ "runtime"
+ "strings"
+ "testing"
+)
+
+func TestCaller(t *testing.T) {
+ procs := runtime.GOMAXPROCS(-1)
+ c := make(chan bool, procs)
+ for p := 0; p < procs; p++ {
+ go func() {
+ for i := 0; i < 1000; i++ {
+ testCallerFoo(t)
+ }
+ c <- true
+ }()
+ defer func() {
+ <-c
+ }()
+ }
+}
+
+func testCallerFoo(t *testing.T) {
+ testCallerBar(t)
+}
+
+func testCallerBar(t *testing.T) {
+ for i := 0; i < 2; i++ {
+ pc, file, line, ok := runtime.Caller(i)
+ f := runtime.FuncForPC(pc)
+ if !ok ||
+ !strings.HasSuffix(file, "symtab_test.go") ||
+ (i == 0 && !strings.HasSuffix(f.Name(), "testCallerBar")) ||
+ (i == 1 && !strings.HasSuffix(f.Name(), "testCallerFoo")) ||
+ line < 5 || line > 1000 ||
+ f.Entry() >= pc {
+ t.Errorf("incorrect symbol info %d: %t %d %d %s %s %d",
+ i, ok, f.Entry(), pc, f.Name(), file, line)
+ }
+ }
+}
