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/gomaxprocs/gomaxprocs.go

@@ -0,0 +1,82 @@
+// Copyright 2025 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 gomaxprocs synchronizes adjustments to GOMAXPROCS. When this package
+// is active (i.e. after the first call to SetBase), it sets the value of
+// GOMAXPROCS to a "base" value (which should be set by a single goroutine,
+// without races) plus a non-negative "temporary" value (which may be
+// concurrently increased or decreased by multiple goroutines).
+//
+// Note that changing GOMAXPROCS stops the world, so callers should adjust
+// GOMAXPROCS infrequently.
+//
+// TODO: Add gomaxprocs.Get() and check that other gVisor packages don't call
+// runtime.GOMAXPROCS() at all.
+package gomaxprocs
+
+import (
+	"runtime"
+
+	"github.com/sagernet/gvisor/pkg/log"
+)
+
+var (
+	mu gomaxprocsMutex
+	// +checklocks:mu
+	base int
+	// +checklocks:mu
+	temp int
+)
+
+// SetBase sets base GOMAXPROCS.
+func SetBase(n int) {
+	if n < 1 {
+		log.Traceback("Invalid base GOMAXPROCS: %d", n)
+		return
+	}
+	mu.Lock()
+	defer mu.Unlock()
+	oldBase := base
+	base = n
+	updateRuntime(oldBase, temp)
+}
+
+// Add adds n temporary GOMAXPROCS. n may be negative; callers should call Add
+// with negative n to remove temporary GOMAXPROCS when they are no longer
+// needed.
+func Add(n int) {
+	mu.Lock()
+	defer mu.Unlock()
+	t := temp + n
+	if t < 0 {
+		log.Traceback("gomaxprocs.Add(%d) would cause temp to become %d", n, t)
+		return
+	}
+	oldTemp := temp
+	temp = t
+	if base != 0 {
+		updateRuntime(base, oldTemp)
+	}
+}
+
+// +checklocks:mu
+func updateRuntime(oldBase, oldTemp int) {
+	n := base + temp
+	log.Debugf("Setting GOMAXPROCS to %d", n)
+	got := runtime.GOMAXPROCS(n)
+	if want := oldBase + oldTemp; oldBase != 0 && got != want {
+		// Something changed GOMAXPROCS outside of our control.
+		log.Warningf("Previous GOMAXPROCS was %d, expected %d = %d + %d", got, want, oldBase, oldTemp)
+	}
+}