runtime: regression test for semasleep indefinite hang
A regression test in which: for a program that invokes semasleep,
we send non-terminal signals such as SIGIO.
Since the signal wakes up pthread_cond_timedwait_relative_np,
after CL 133655, we should only re-spin for the amount of
time left, instead of re-spinning with the original duration
which would cause an indefinite spin.
Updates #27520
Change-Id: I744a6d04cf8923bc4e13649446aff5e42b7de5d8
Reviewed-on: https://go-review.googlesource.com/135015
Run-TryBot: Emmanuel Odeke <emm.odeke@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
diff --git a/src/runtime/semasleep_test.go b/src/runtime/semasleep_test.go
new file mode 100644
index 0000000..4a8b4db
--- /dev/null
+++ b/src/runtime/semasleep_test.go
@@ -0,0 +1,88 @@
+// Copyright 2018 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.
+
+//+build !nacl,!windows,!js
+
+package runtime_test
+
+import (
+ "internal/testenv"
+ "io/ioutil"
+ "os"
+ "os/exec"
+ "path/filepath"
+ "syscall"
+ "testing"
+ "time"
+)
+
+// Issue #27250. Spurious wakeups to pthread_cond_timedwait_relative_np
+// shouldn't cause semasleep to retry with the same timeout which would
+// cause indefinite spinning.
+func TestSpuriousWakeupsNeverHangSemasleep(t *testing.T) {
+ testenv.MustHaveGoBuild(t)
+ tempDir, err := ioutil.TempDir("", "issue-27250")
+ if err != nil {
+ t.Fatalf("Failed to create the temp directory: %v", err)
+ }
+ defer os.RemoveAll(tempDir)
+
+ repro := `
+ package main
+
+ import "time"
+
+ func main() {
+ <-time.After(1 * time.Second)
+ }
+ `
+ mainPath := filepath.Join(tempDir, "main.go")
+ if err := ioutil.WriteFile(mainPath, []byte(repro), 0644); err != nil {
+ t.Fatalf("Failed to create temp file for repro.go: %v", err)
+ }
+ binaryPath := filepath.Join(tempDir, "binary")
+
+ // Build the binary so that we can send the signal to its PID.
+ out, err := exec.Command(testenv.GoToolPath(t), "build", "-o", binaryPath, mainPath).CombinedOutput()
+ if err != nil {
+ t.Fatalf("Failed to compile the binary: err: %v\nOutput: %s\n", err, out)
+ }
+ if err := os.Chmod(binaryPath, 0755); err != nil {
+ t.Fatalf("Failed to chmod binary: %v", err)
+ }
+
+ // Now run the binary.
+ cmd := exec.Command(binaryPath)
+ if err := cmd.Start(); err != nil {
+ t.Fatalf("Failed to start command: %v", err)
+ }
+ doneCh := make(chan error, 1)
+ go func() {
+ doneCh <- cmd.Wait()
+ }()
+
+ // With the repro running, we can continuously send to it
+ // a non-terminal signal such as SIGIO, to spuriously
+ // wakeup pthread_cond_timedwait_relative_np.
+ unfixedTimer := time.NewTimer(2 * time.Second)
+ for {
+ select {
+ case <-time.After(200 * time.Millisecond):
+ // Send the pesky signal that toggles spinning
+ // indefinitely if #27520 is not fixed.
+ cmd.Process.Signal(syscall.SIGIO)
+
+ case <-unfixedTimer.C:
+ t.Error("Program failed to return on time and has to be killed, issue #27520 still exists")
+ cmd.Process.Signal(syscall.SIGKILL)
+ return
+
+ case err := <-doneCh:
+ if err != nil {
+ t.Fatalf("The program returned but unfortunately with an error: %v", err)
+ }
+ return
+ }
+ }
+}
