From: Michael Froman <mfroman@mozilla.com>
Date: Fri, 9 Jul 2021 18:14:00 -0500
Subject: Bug 1654112 - mutex changes to fix tsan errors. r=ng

Differential Revision: https://phabricator.services.mozilla.com/D119674
Mercurial Revision: https://hg.mozilla.org/mozilla-central/rev/3d5503acf9a4b22e02c4300f29e4fbfed406ea2c
---
 rtc_base/logging.cc | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/rtc_base/logging.cc b/rtc_base/logging.cc
index de97fe9446..4e0b9ac800 100644
--- a/rtc_base/logging.cc
+++ b/rtc_base/logging.cc
@@ -279,8 +279,8 @@ void LogMessage::LogTimestamps(bool on) {
 }
 
 void LogMessage::LogToDebug(LoggingSeverity min_sev) {
-  g_dbg_sev = min_sev;
   MutexLock lock(&GetLoggingLock());
+  g_dbg_sev = min_sev;
   UpdateMinLogSeverity();
 }
 
@@ -464,6 +464,9 @@ void LogMessage::OutputToDebug(const LogLineRef& log_line) {
 
 // static
 bool LogMessage::IsNoop(LoggingSeverity severity) {
+  // Added MutexLock to fix tsan warnings on accessing g_dbg_sev. (mjf)
+  // See https://bugs.chromium.org/p/chromium/issues/detail?id=1228729
+  webrtc::MutexLock lock(&GetLoggingLock());
   if (severity >= g_dbg_sev || severity >= g_min_sev)
     return false;
   return streams_empty_.load(std::memory_order_relaxed);