snapshot: sagernet/gvisor v0.0.0-20250811.0-sing-box-mod.1

Содержимое пина, зафиксированного в go.mod sing-box-lx, одним коммитом
без истории. Полная история SagerNet/gvisor — 1.45 ГБ и клонируется в
каждой CI-джобе; наша дельта — одна вставка в одну функцию, история для
неё не нужна.

Module path github.com/sagernet/gvisor сохранён намеренно: на него
опирается replace-директива суперпроекта.

Патч поверх — отдельным коммитом, чтобы дельта читалась одним git show
и переносилась на новый пин копированием.

SPECS/TASKS/048-GVISOR_HANDSHAKE_NIL_CRASH

pkg/sync/mutex_unsafe.go

@@ -0,0 +1,80 @@
+// Copyright 2019 The gVisor Authors.
+//
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file or at
+// https://developers.google.com/open-source/licenses/bsd.
+
+package sync
+
+import (
+	"sync"
+	"unsafe"
+)
+
+// CrossGoroutineMutex is equivalent to Mutex, but it need not be unlocked by a
+// the same goroutine that locked the mutex.
+type CrossGoroutineMutex struct {
+	m sync.Mutex
+}
+
+// Lock locks the underlying Mutex.
+// +checklocksignore
+func (m *CrossGoroutineMutex) Lock() {
+	m.m.Lock()
+}
+
+// Unlock unlocks the underlying Mutex.
+// +checklocksignore
+func (m *CrossGoroutineMutex) Unlock() {
+	m.m.Unlock()
+}
+
+// TryLock tries to acquire the mutex. It returns true if it succeeds and false
+// otherwise. TryLock does not block.
+func (m *CrossGoroutineMutex) TryLock() bool {
+	return m.m.TryLock()
+}
+
+// Mutex is a mutual exclusion lock. The zero value for a Mutex is an unlocked
+// mutex.
+//
+// A Mutex must not be copied after first use.
+//
+// A Mutex must be unlocked by the same goroutine that locked it. This
+// invariant is enforced with the 'checklocks' build tag.
+type Mutex struct {
+	m CrossGoroutineMutex
+}
+
+// Lock locks m. If the lock is already in use, the calling goroutine blocks
+// until the mutex is available.
+// +checklocksignore
+func (m *Mutex) Lock() {
+	noteLock(unsafe.Pointer(m))
+	m.m.Lock()
+}
+
+// Unlock unlocks m.
+//
+// Preconditions:
+//   - m is locked.
+//   - m was locked by this goroutine.
+//
+// +checklocksignore
+func (m *Mutex) Unlock() {
+	noteUnlock(unsafe.Pointer(m))
+	m.m.Unlock()
+}
+
+// TryLock tries to acquire the mutex. It returns true if it succeeds and false
+// otherwise. TryLock does not block.
+// +checklocksignore
+func (m *Mutex) TryLock() bool {
+	// Note lock first to enforce proper locking even if unsuccessful.
+	noteLock(unsafe.Pointer(m))
+	locked := m.m.TryLock()
+	if !locked {
+		noteUnlock(unsafe.Pointer(m))
+	}
+	return locked
+}