From 48fde62a6fe1cf4083b0c775f60ee21f2554763e Mon Sep 17 00:00:00 2001
From: Tom Englund <tomenglund26@gmail.com>
Date: Sat, 10 Aug 2024 16:40:09 +0200
Subject: [PATCH] watchdog: avoid data races in watchdog

asan thread sanitizer reported data races in the watchdog from reading
and setting the bool variables make them std::atomic bools. also add a
atomic bool for the main thread to wait for to avoid data race when
reading the config values.
---
 src/Compositor.cpp       |  3 +++
 src/helpers/Watchdog.cpp | 13 ++++++-------
 src/helpers/Watchdog.hpp |  9 +++++----
 3 files changed, 14 insertions(+), 11 deletions(-)

diff --git a/src/Compositor.cpp b/src/Compositor.cpp
index e3a347fd9dd2..b2dc2cf01872 100644
--- a/src/Compositor.cpp
+++ b/src/Compositor.cpp
@@ -552,6 +552,9 @@ void CCompositor::initManagers(eManagersInitStage stage) {
 
             g_pConfigManager->init();
             g_pWatchdog = std::make_unique<CWatchdog>(); // requires config
+            // wait for watchdog to initialize to not hit data races in reading config values.
+            while (!g_pWatchdog->m_bWatchdogInitialized)
+                std::this_thread::yield();
 
             Debug::log(LOG, "Creating the PointerManager!");
             g_pPointerManager = std::make_unique<CPointerManager>();
diff --git a/src/helpers/Watchdog.cpp b/src/helpers/Watchdog.cpp
index b9f654daf1c2..c7ff648ba5f5 100644
--- a/src/helpers/Watchdog.cpp
+++ b/src/helpers/Watchdog.cpp
@@ -18,15 +18,14 @@ CWatchdog::CWatchdog() {
     m_pWatchdog = std::make_unique<std::thread>([this] {
         static auto PTIMEOUT = CConfigValue<Hyprlang::INT>("debug:watchdog_timeout");
 
-        while (1337) {
-            std::unique_lock lk(m_mWatchdogMutex);
+        m_bWatchdogInitialized = true;
+        while (!m_bExitThread) {
+            std::unique_lock<std::mutex> lk(m_mWatchdogMutex);
 
             if (!m_bWillWatch)
-                m_cvWatchdogCondition.wait(lk, [this] { return m_bNotified; });
-            else {
-                if (m_cvWatchdogCondition.wait_for(lk, std::chrono::milliseconds((int)(*PTIMEOUT * 1000.0)), [this] { return m_bNotified; }) == false)
-                    pthread_kill(m_iMainThreadPID, SIGUSR1);
-            }
+                m_cvWatchdogCondition.wait(lk, [this] { return m_bNotified || m_bExitThread; });
+            else if (m_cvWatchdogCondition.wait_for(lk, std::chrono::milliseconds((int)(*PTIMEOUT * 1000.0)), [this] { return m_bNotified || m_bExitThread; }) == false)
+                pthread_kill(m_iMainThreadPID, SIGUSR1);
 
             if (m_bExitThread)
                 break;
diff --git a/src/helpers/Watchdog.hpp b/src/helpers/Watchdog.hpp
index 7bb499d69318..a21e692e9ef1 100644
--- a/src/helpers/Watchdog.hpp
+++ b/src/helpers/Watchdog.hpp
@@ -14,18 +14,19 @@ class CWatchdog {
     void startWatching();
     void endWatching();
 
+    std::atomic<bool>                              m_bWatchdogInitialized{false};
   private:
     std::chrono::high_resolution_clock::time_point m_tTriggered;
 
     pthread_t                                      m_iMainThreadPID = 0;
 
-    bool                                           m_bWatching  = false;
-    bool                                           m_bWillWatch = false;
+    std::atomic<bool>                              m_bWatching  = false;
+    std::atomic<bool>                              m_bWillWatch = false;
 
     std::unique_ptr<std::thread>                   m_pWatchdog;
     std::mutex                                     m_mWatchdogMutex;
-    bool                                           m_bNotified   = false;
-    bool                                           m_bExitThread = false;
+    std::atomic<bool>                              m_bNotified   = false;
+    std::atomic<bool>                              m_bExitThread = false;
     std::condition_variable                        m_cvWatchdogCondition;
 };