Adding upstream version 1.21.8.upstream/1.21.8

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 121 insertions, 0 deletions

diff --git a/src/runtime/semasleep_test.go b/src/runtime/semasleep_test.go
new file mode 100644
index 0000000..711d5df
--- /dev/null
+++ b/src/runtime/semasleep_test.go
@@ -0,0 +1,121 @@
+// 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.
+
+//go:build !plan9 && !windows && !js && !wasip1
+
+package runtime_test
+
+import (
+	"io"
+	"os/exec"
+	"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) {
+	if *flagQuick {
+		t.Skip("-quick")
+	}
+	t.Parallel() // Waits for a program to sleep for 1s.
+
+	exe, err := buildTestProg(t, "testprog")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	cmd := exec.Command(exe, "After1")
+	stdout, err := cmd.StdoutPipe()
+	if err != nil {
+		t.Fatalf("StdoutPipe: %v", err)
+	}
+	beforeStart := time.Now()
+	if err := cmd.Start(); err != nil {
+		t.Fatalf("Failed to start command: %v", err)
+	}
+
+	waiting := false
+	doneCh := make(chan error, 1)
+	t.Cleanup(func() {
+		cmd.Process.Kill()
+		if waiting {
+			<-doneCh
+		} else {
+			cmd.Wait()
+		}
+	})
+
+	// Wait for After1 to close its stdout so that we know the runtime's SIGIO
+	// handler is registered.
+	b, err := io.ReadAll(stdout)
+	if len(b) > 0 {
+		t.Logf("read from testprog stdout: %s", b)
+	}
+	if err != nil {
+		t.Fatalf("error reading from testprog: %v", err)
+	}
+
+	// Wait for child exit.
+	//
+	// Note that we must do this after waiting for the write/child end of
+	// stdout to close. Wait closes the read/parent end of stdout, so
+	// starting this goroutine prior to io.ReadAll introduces a race
+	// condition where ReadAll may get fs.ErrClosed if the child exits too
+	// quickly.
+	waiting = true
+	go func() {
+		doneCh <- cmd.Wait()
+		close(doneCh)
+	}()
+
+	// Wait for an arbitrary timeout longer than one second. The subprocess itself
+	// attempts to sleep for one second, but if the machine running the test is
+	// heavily loaded that subprocess may not schedule very quickly even if the
+	// bug remains fixed. (This is fine, because if the bug really is unfixed we
+	// can keep the process hung indefinitely, as long as we signal it often
+	// enough.)
+	timeout := 10 * time.Second
+
+	// The subprocess begins sleeping for 1s after it writes to stdout, so measure
+	// the timeout from here (not from when we started creating the process).
+	// That should reduce noise from process startup overhead.
+	ready := time.Now()
+
+	// With the repro running, we can continuously send to it
+	// a signal that the runtime considers non-terminal,
+	// such as SIGIO, to spuriously wake up
+	// pthread_cond_timedwait_relative_np.
+	ticker := time.NewTicker(200 * time.Millisecond)
+	defer ticker.Stop()
+	for {
+		select {
+		case now := <-ticker.C:
+			if now.Sub(ready) > timeout {
+				t.Error("Program failed to return on time and has to be killed, issue #27520 still exists")
+				// Send SIGQUIT to get a goroutine dump.
+				// Stop sending SIGIO so that the program can clean up and actually terminate.
+				cmd.Process.Signal(syscall.SIGQUIT)
+				return
+			}
+
+			// Send the pesky signal that toggles spinning
+			// indefinitely if #27520 is not fixed.
+			cmd.Process.Signal(syscall.SIGIO)
+
+		case err := <-doneCh:
+			if err != nil {
+				t.Fatalf("The program returned but unfortunately with an error: %v", err)
+			}
+			if time.Since(beforeStart) < 1*time.Second {
+				// The program was supposed to sleep for a full (monotonic) second;
+				// it should not return before that has elapsed.
+				t.Fatalf("The program stopped too quickly.")
+			}
+			return
+		}
+	}
+}