From 06a12246f5d8966531bd8afd2e2f5254295970a1 Mon Sep 17 00:00:00 2001
From: smallmodel <15067410+smallmodel@users.noreply.github.com>
Date: Thu, 13 Mar 2025 22:37:21 +0100
Subject: [PATCH] Notify the request thread of shutdown only if it's waiting

This avoids a deadlock that would occur if notify_all() is called before the thread is waiting
---
 code/sys/sys_update_checker.cpp | 22 ++++++++++++----------
 code/sys/sys_update_checker.h   |  1 -
 2 files changed, 12 insertions(+), 11 deletions(-)

diff --git a/code/sys/sys_update_checker.cpp b/code/sys/sys_update_checker.cpp
index d40d8060..c7915503 100644
--- a/code/sys/sys_update_checker.cpp
+++ b/code/sys/sys_update_checker.cpp
@@ -210,7 +210,13 @@ void UpdateCheckerThread::Shutdown()
 
     if (osThread) {
         // Notify and shutdown the thread
-        clientWake.notify_all();
+        {
+            // Wait until the request thread is ready
+            std::lock_guard<std::mutex> l(clientWakeMutex);
+            clientWake.notify_all();
+        }
+
+        // Wait for the thread to exit
         osThread->join();
 
         delete osThread;
@@ -358,19 +364,15 @@ void UpdateCheckerThread::RequestThread()
     InitClient();
 
     while (handle && shouldBeActive) {
+        std::unique_lock<std::mutex> l(clientWakeMutex);
         DoRequest();
-        RequestThreadSleep();
+
+        const std::chrono::seconds interval = std::chrono::seconds(Q_max(1, com_updatecheck_interval->integer) * 60);
+
+        clientWake.wait_for(l, interval);
     }
 
     ShutdownClient();
 
     requestThreadIsActive = qfalse;
 }
-
-void UpdateCheckerThread::RequestThreadSleep()
-{
-    const std::chrono::seconds interval = std::chrono::seconds(Q_max(1, com_updatecheck_interval->integer) * 60);
-
-    std::unique_lock<std::mutex> l(clientWakeMutex);
-    clientWake.wait_for(l, interval);
-}
diff --git a/code/sys/sys_update_checker.h b/code/sys/sys_update_checker.h
index e3905012..ac5e8748 100644
--- a/code/sys/sys_update_checker.h
+++ b/code/sys/sys_update_checker.h
@@ -61,7 +61,6 @@ private:
 
     bool ParseVersionNumber(const char *value, int& major, int& minor, int& patch) const;
     void RequestThread();
-    void RequestThreadSleep();
     void DoRequest();
 
 private: