From 9bbfe9e5e09e12ea78048c610de85aeb5970176e Mon Sep 17 00:00:00 2001
From: Florent Castelli <orphis@webrtc.org>
Date: Mon, 21 Feb 2022 14:39:47 +0100
Subject: [PATCH] dcsctp: Fix data race in debug logging

The variable instance_count might be accessed from multiple threads when
different PeerConnectionFactory objects are used, which may create
multiple network threads. This is a pattern mostly noticed in tests.

This fixes issues with logging when run under TSAN, it should not have
any production impact.

Bug: chromium:1243702
Change-Id: Iab1412a7907545811a309cab27a3ae23b4718606
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/251983
Auto-Submit: Florent Castelli <orphis@webrtc.org>
Reviewed-by: Victor Boivie <boivie@google.com>
Commit-Queue: Florent Castelli <orphis@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#36045}
---
 media/sctp/dcsctp_transport.cc | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/media/sctp/dcsctp_transport.cc b/media/sctp/dcsctp_transport.cc
index 38d2799f36..0a671ced87 100644
--- a/media/sctp/dcsctp_transport.cc
+++ b/media/sctp/dcsctp_transport.cc
@@ -10,6 +10,7 @@
 
 #include "media/sctp/dcsctp_transport.h"
 
+#include <atomic>
 #include <cstdint>
 #include <limits>
 #include <utility>
@@ -126,7 +127,7 @@ DcSctpTransport::DcSctpTransport(rtc::Thread* network_thread,
             socket_->HandleTimeout(timeout_id);
           }) {
   RTC_DCHECK_RUN_ON(network_thread_);
-  static int instance_count = 0;
+  static std::atomic<int> instance_count = 0;
   rtc::StringBuilder sb;
   sb << debug_name_ << instance_count++;
   debug_name_ = sb.Release();