runtime: don't run TestCrashDumpsAllThreads in parallel

It sometimes seems to time out on slow systems, perhaps due to
being run at the same time as a lot of other work.

Also move the code to testdata/testprog, so that we don't have to
build it separately.

I hope that this
Fixes #35356

Change-Id: I875b858fa23836513ae14d3116461e22fffd5352
Reviewed-on: https://go-review.googlesource.com/c/go/+/312510
Trust: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Go Bot <gobot@golang.org>

1 files changed, 47 insertions, 0 deletions

diff --git a/src/runtime/testdata/testprog/crashdump.go b/src/runtime/testdata/testprog/crashdump.go
new file mode 100644
index 0000000000..bced397b8a
--- /dev/null
+++ b/src/runtime/testdata/testprog/crashdump.go
@@ -0,0 +1,47 @@
+// Copyright 2021 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
+
+import (
+	"fmt"
+	"os"
+	"runtime"
+)
+
+func init() {
+	register("CrashDumpsAllThreads", CrashDumpsAllThreads)
+}
+
+func CrashDumpsAllThreads() {
+	const count = 4
+	runtime.GOMAXPROCS(count + 1)
+
+	chans := make([]chan bool, count)
+	for i := range chans {
+		chans[i] = make(chan bool)
+		go crashDumpsAllThreadsLoop(i, chans[i])
+	}
+
+	// Wait for all the goroutines to start executing.
+	for _, c := range chans {
+		<-c
+	}
+
+	// Tell our parent that all the goroutines are executing.
+	if _, err := os.NewFile(3, "pipe").WriteString("x"); err != nil {
+		fmt.Fprintf(os.Stderr, "write to pipe failed: %v\n", err)
+		os.Exit(2)
+	}
+
+	select {}
+}
+
+func crashDumpsAllThreadsLoop(i int, c chan bool) {
+	close(c)
+	for {
+		for j := 0; j < 0x7fffffff; j++ {
+		}
+	}
+}