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/locking/locking.go

@@ -0,0 +1,28 @@
+// Copyright 2022 The gVisor Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package locking implements lock primitives with the correctness validator.
+//
+// All mutexes are divided on classes and the validator check following conditions:
+//   - Mutexes of the same class are not taken more than once except cases when
+//     that is expected.
+//   - Mutexes are never locked in a reverse order. Lock dependencies are tracked
+//     on the class level.
+//
+// The validator is implemented in a very straightforward way. For each mutex
+// class, we maintain the ancestors list of all classes that have ever been
+// taken before the target one. For each goroutine, we have the list of
+// currently locked mutexes. And finally, all lock methods check that
+// ancestors of currently locked mutexes don't contain the target one.
+package locking