// Transfer locked-ness to the new goroutine.
		// Save lock state to restore later.
		mp := gp.m
		if mp != gp.lockedm.ptr() {
			throw("inconsistent lockedm")
		}
		// Save the external lock count and clear it so
		// that it can't be unlocked from the debug call.
		// Note: we already locked internally to the thread,
		// so if we were locked before we're still locked now.

		casgstatus(gnext, _Gwaiting, _Grunnable)
		casgstatus(gnext, _Grunnable, _Grunning)
	}

	// Donate locked state.
	if locked {
		mp.lockedg.set(gnext)
		gnext.lockedm.set(mp)
	}

	// Release the trace locker. We've completed all the necessary transitions..
	if trace.ok() {
		traceRelease(trace)
	}

	// Switch to gnext. Does not return.
	gogo(&gnext.sched)

// will send SIGTRAP to thread ID tid. gp must be locked to its OS thread and
// running.
//
// On success, InjectDebugCall returns the panic value of fn or nil.
// If fn did not panic, its results will be available in args.
func InjectDebugCall(gp *g, fn any, regArgs *abi.RegArgs, stackArgs any, tkill func(tid int) error, returnOnUnsafePoint bool) (any, error) {
	if gp.lockedm == 0 {
		return nil, plainError("goroutine not locked to thread")

	var wl RWMutex
	var rl Locker
	wlocked := make(chan bool, 1)
	rlocked := make(chan bool, 1)
	rl = wl.RLocker()
	n := 10
	go func() {
		for i := 0; i < n; i++ {
			rl.Lock()
			rl.Lock()
			rlocked <- true
			wl.Lock()
			wlocked <- true
		}
	}()
	for i := 0; i < n; i++ {
		<-rlocked
		rl.Unlock()
		select {
		case <-wlocked:
			t.Fatal("RLocker() didn't read-lock it")

	wl := NewLRWMutex()
	var rl sync.Locker
	wlocked := make(chan bool, 1)
	rlocked := make(chan bool, 1)
	rl = wl.DRLocker()
	n := 10
	go func() {
		for i := 0; i < n; i++ {
			rl.Lock()
			rl.Lock()
			rlocked <- true
			wl.Lock()
			wlocked <- true
		}
	}()
	for i := 0; i < n; i++ {
		<-rlocked
		rl.Unlock()
		select {
		case <-wlocked:
			t.Fatal("RLocker() didn't read-lock it")

	String() string

	// Close closes any underlying connection to the service endpoint
	Close() error

	// Is the underlying connection online? (is always true for any local lockers)
	IsOnline() bool

	// Is the underlying locker local to this server?
	IsLocal() bool

					break
				}
				v = atomic.Loaduintptr(&l.key)
				if v&locked == 0 {
					continue Loop
				}
			}
			if v&locked != 0 {
				// Queued. Wait.
				semasleep(-1)
				i = 0
			}
		}
	}
}

func unlock(l *mutex) {
	unlockWithRank(l)
}

// We might not be holding a p in this code.
//
//go:nowritebarrier
func unlock2(l *mutex) {
	gp := getg()
	var mp *m

	expected := true
	if locked != expected {
		t.Errorf("TestSimpleWriteLockAcquired(): \nexpected %#v\ngot      %#v", expected, locked)
	}
}

func TestSimpleWriteLockTimedOut(t *testing.T) {
	locked := testSimpleWriteLock(t, testDrwMutexAcquireTimeout)

	expected := false
	if locked != expected {
		t.Errorf("TestSimpleWriteLockTimedOut(): \nexpected %#v\ngot      %#v", expected, locked)
	}
}

			lm.ref = 1
			lm.isWriteLock = true
			locked = true
		}
	} else {
		if !lm.isWriteLock {
			lm.ref++
			locked = true
		}
	}

	return locked
}

const (
	lockRetryInterval = 50 * time.Millisecond
)

// lockLoop will acquire either a read or a write lock
//
// The call will block until the lock is granted using a built-in
// timing randomized back-off algorithm to try again until successful

// open file descriptor.
package lock

import (
	"errors"
	"os"
	"sync"
)

// ErrAlreadyLocked is returned if the underlying fd is already locked.
var ErrAlreadyLocked = errors.New("file already locked")

// RLockedFile represents a read locked file, implements a special
// closer which only closes the associated *os.File when the ref count.
// has reached zero, i.e when all the readers have given up their locks.