testCrashHandler(t, false)
}

func testDeadlock(t *testing.T, name string) {
	// External linking brings in cgo, causing deadlock detection not working.
	testenv.MustInternalLink(t, false)

	output := runTestProg(t, "testprog", name)
	want := "fatal error: all goroutines are asleep - deadlock!\n"
	if !strings.HasPrefix(output, want) {
		t.Fatalf("output does not start with %q:\n%s", want, output)
	}
}

	mp := acquirem()
	pp := mp.p.ptr()
	if len(pp.deferpool) == 0 && sched.deferpool != nil {
		lock(&sched.deferlock)
		for len(pp.deferpool) < cap(pp.deferpool)/2 && sched.deferpool != nil {
			d := sched.deferpool
			sched.deferpool = d.link
			d.link = nil
			pp.deferpool = append(pp.deferpool, d)
		}
		unlock(&sched.deferlock)
	}
	if n := len(pp.deferpool); n > 0 {
		d = pp.deferpool[n-1]
		pp.deferpool[n-1] = nil

// the current M (if any) must be in a preemptible state. This
// prevents deadlocks where two goroutines attempt to suspend each
// other and both are in non-preemptible states. There are other ways
// to resolve this deadlock, but this seems simplest.
//
// TODO(austin): What if we instead required this to be called from a
// user goroutine? Then we could deschedule the goroutine while

			// CreateThread may fail if called
			// concurrently with ExitProcess. If this
			// happens, just freeze this thread and let
			// the process exit. See issue #18253.
			lock(&deadlock)
			lock(&deadlock)
		}
		print("runtime: failed to create new OS thread (have ", mcount(), " already; errno=", getlasterror(), ")\n")
		throw("runtime.newosproc")
	}

	lockRankGlobalAlloc:     "globalAlloc",
	lockRankTrace:           "trace",
	lockRankTraceStackTab:   "traceStackTab",
	lockRankPanic:           "panic",
	lockRankDeadlock:        "deadlock",
	lockRankRaceFini:        "raceFini",
	lockRankAllocmRInternal: "allocmRInternal",
	lockRankExecRInternal:   "execRInternal",
	lockRankTestRInternal:   "testRInternal",
}

//
//go:systemstack
func stackalloc(n uint32) stack {
	// Stackalloc must be called on scheduler stack, so that we
	// never try to grow the stack during the code that stackalloc runs.
	// Doing so would cause a deadlock (issue 1547).
	thisg := getg()
	if thisg != thisg.m.g0 {
		throw("stackalloc not on scheduler stack")
	}
	if n&(n-1) != 0 {
		throw("stack size not a power of 2")
	}
	if stackDebug >= 1 {

	// lock protects all fields in hchan, as well as several
	// fields in sudogs blocked on this channel.
	//
	// Do not change another G's status while holding this lock
	// (in particular, do not ready a G), as this can deadlock
	// with stack shrinking.
	lock mutex
}

type waitq struct {
	first *sudog
	last  *sudog
}

//go:linkname reflect_makechan reflect.makechan
func reflect_makechan(t *chantype, size int) *hchan {

	// will exit before the parallel children are executed. It should be noted that if the parent test is prevented
	// from exiting (e.g. parent test is waiting for something to occur within the child test), the test will
	// deadlock.
	//
	// Example:
	//
	// func TestParallel(t *testing.T) {
	//     framework.NewTest(t).
	//         Run(func(ctx framework.TestContext) {
	//             ctx.NewSubTest("T1").

    // CrossReplicaAndPartition:
    // Even though TF2XLA will setup the device assignment to include
    // devices in this group as replicas before launching this module,
    // "CrossReplica" mode (no channel) produces a deadlock when
    // not using XLA SPMD expansion.
    int64_t channel_id = channel_id_++;
    return ConvertAllReduce(
        rewriter, channel_id, all_reduce.getType(), replica_groups,

	// also no stale generation values left. Therefore, it's safe to flush
	// any buffers that remain in that generation's slot.
	const debugDeadlock = false
	systemstack(func() {
		// Track iterations for some rudimentary deadlock detection.
		i := 0
		detectedDeadlock := false

		for mToFlush != nil {
			prev := &mToFlush
			for mp := *prev; mp != nil; {
				if mp.trace.seqlock.Load()%2 != 0 {