From 7da5dae6502b787fc6d903863e9a6c5043d107a2 Mon Sep 17 00:00:00 2001
From: SakuraBurst <56797965+SakuraBurst@users.noreply.github.com>
Date: Mon, 5 Oct 2026 11:49:16 +0300
Subject: [PATCH] Mux client: Fix a race condition between Dispatch and
 SessionManager.Close (#6871)
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Fixes https://github.com/XTLS/Xray-core/issues/6870

---------

Co-authored-by: 风扇滑翔翼 <Fangliding.fshxy@outlook.com>
---
 common/mux/client.go       | 4 +---
 common/mux/session.go      | 4 +++-
 common/mux/session_test.go | 6 +++---
 3 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/common/mux/client.go b/common/mux/client.go
index 0463be5fc..1d0180eef 100644
--- a/common/mux/client.go
+++ b/common/mux/client.go
@@ -314,12 +314,10 @@ func (m *ClientWorker) Dispatch(ctx context.Context, link *transport.Link) bool
 	}
 
 	sm := m.sessionManager
-	s := sm.Allocate(&m.strategy)
+	s := sm.Allocate(&m.strategy, link.Reader, link.Writer)
 	if s == nil {
 		return false
 	}
-	s.input = link.Reader
-	s.output = link.Writer
 	go fetchInput(ctx, s, m.link.Writer)
 	if _, ok := link.Reader.(*pipe.Reader); !ok {
 		select {
diff --git a/common/mux/session.go b/common/mux/session.go
index 66b9674cf..53bc53569 100644
--- a/common/mux/session.go
+++ b/common/mux/session.go
@@ -51,7 +51,7 @@ func (m *SessionManager) Count() int {
 	return int(m.count)
 }
 
-func (m *SessionManager) Allocate(Strategy *ClientStrategy) *Session {
+func (m *SessionManager) Allocate(Strategy *ClientStrategy, input buf.Reader, output buf.Writer) *Session {
 	m.Lock()
 	defer m.Unlock()
 
@@ -64,6 +64,8 @@ func (m *SessionManager) Allocate(Strategy *ClientStrategy) *Session {
 
 	m.count++
 	s := &Session{
+		input:  input,
+		output: output,
 		ID:     m.count,
 		parent: m,
 		done:   done.New(),
diff --git a/common/mux/session_test.go b/common/mux/session_test.go
index 8ef278778..7c47cb052 100644
--- a/common/mux/session_test.go
+++ b/common/mux/session_test.go
@@ -9,7 +9,7 @@ import (
 func TestSessionManagerAdd(t *testing.T) {
 	m := NewSessionManager()
 
-	s := m.Allocate(&ClientStrategy{})
+	s := m.Allocate(&ClientStrategy{}, nil, nil)
 	if s.ID != 1 {
 		t.Error("id: ", s.ID)
 	}
@@ -17,7 +17,7 @@ func TestSessionManagerAdd(t *testing.T) {
 		t.Error("size: ", m.Size())
 	}
 
-	s = m.Allocate(&ClientStrategy{})
+	s = m.Allocate(&ClientStrategy{}, nil, nil)
 	if s.ID != 2 {
 		t.Error("id: ", s.ID)
 	}
@@ -39,7 +39,7 @@ func TestSessionManagerAdd(t *testing.T) {
 
 func TestSessionManagerClose(t *testing.T) {
 	m := NewSessionManager()
-	s := m.Allocate(&ClientStrategy{})
+	s := m.Allocate(&ClientStrategy{}, nil, nil)
 
 	if m.CloseIfNoSessionAndIdle(m.Size(), m.Count()) {
 		t.Error("able to close")