registerInit("LockOSThreadAlt", func() {
		// Lock the OS thread now so main runs on the main thread.
		runtime.LockOSThread()
	})
	register("LockOSThreadAlt", LockOSThreadAlt)

	registerInit("LockOSThreadAvoidsStatePropagation", func() {
		// Lock the OS thread now so main runs on the main thread.
		runtime.LockOSThread()
	})
	register("LockOSThreadAvoidsStatePropagation", LockOSThreadAvoidsStatePropagation)

	n := 0
	next, _ := iter.Pull(i)
	for {
		runtime.LockOSThread()
		n++
		v, ok := next()
		if !ok {
			break
		}
		if v != 5 {
			return fmt.Errorf("bad iterator: wanted value %d, got %d", 5, v)
		}
	}
	for range n {
		runtime.UnlockOSThread()
	}
	return nil
}

func callerStopLocked(i iter.Seq[int]) error {
	runtime.LockOSThread()
	next, stop := iter.Pull(i)
	v, _ := next()

// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

// Tests a many interesting cases (network, syscalls, a little GC, busy goroutines,
// blocked goroutines, LockOSThread, pipes, and GOMAXPROCS).

//go:build ignore

package main

import (
	"log"
	"net"
	"os"
	"runtime"
	"runtime/trace"
	"sync"
	"time"
)

func main() {
	var wg sync.WaitGroup

	var s *string
	_ = *s
	fmt.Print("SHOULD NOT BE HERE")
}

func testInNewThread(name string) {
	c := make(chan bool)
	go func() {
		runtime.LockOSThread()
		test(name)
		c <- true
	}()
	<-c
}

func Crash() {
	runtime.LockOSThread()
	test("main")
	testInNewThread("new-thread")
	testInNewThread("second-new-thread")
	test("main-again")
}

type P string

func (p P) String() string {

// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

// Tests a many interesting cases (network, syscalls, a little GC, busy goroutines,
// blocked goroutines, LockOSThread, pipes, and GOMAXPROCS).

//go:build ignore

package main

import (
	"bytes"
	"io"
	"log"
	"net"
	"os"
	"runtime"
	"runtime/trace"
	"sync"
	"time"
)

func main() {

// (locked to OS thread). Otherwise return false.
func fixwd(paths ...string) bool {
	for _, path := range paths {
		if path != "" && path[0] != '/' && path[0] != '#' {
			runtime.LockOSThread()
			Fixwd()
			return true
		}
	}
	return false
}

// goroutine-specific getwd
func getwd() (wd string, err error) {
	fd, err := open(".", O_RDONLY)
	if err != nil {
		return "", err
	}

// pointer errors.
type coro struct {
	gp guintptr
	f  func(*coro)

	// State for validating thread-lock interactions.
	mp        *m
	lockedExt uint32 // mp's external LockOSThread counter at coro creation time.
	lockedInt uint32 // mp's internal lockOSThread counter at coro creation time.
}

//go:linkname newcoro

// newcoro creates a new coro containing a
// goroutine blocked waiting to run f
// and returns that coro.

	//
	// Debuggers rely on us running on the same thread until we get to
	// dispatch the function they asked as to.
	//
	// We're going to transfer this to the new G we just created.
	lockOSThread()

	// Create a new goroutine to execute the call on. Run this on
	// the system stack to avoid growing our stack.
	systemstack(func() {
		// TODO(mknyszek): It would be nice to wrap these arguments in an allocated

	// leave the thread locked to die without a risk of the current thread
	// left lingering with incorrect namespace.
	var innerError error
	go func() {
		defer wg.Done()
		runtime.LockOSThread()
		innerError = containedCall()
	}()
	wg.Wait()

	return innerError

				if e != 0 {
					return e
				}
				return nil
			},
		},
	}

	waiter := func(q <-chan uintptr, r chan<- uintptr, once bool) {
		for x := range q {
			runtime.LockOSThread()
			v, _, e := syscall.Syscall(syscall.SYS_PRCTL, PR_GET_KEEPCAPS, 0, 0)
			if e != 0 {
				t.Errorf("tid=%d prctl(PR_GET_KEEPCAPS) failed: %v", syscall.Gettid(), e)
			} else if x != v {