Merge pull request #519 from sandro97git/set-callback-fix-potential-d…

…eadlock Fix potential deadlock in set_callback
eclipse-paho · Jan 3, 2025 · 461f765 · 461f765
2 parents 7b2b3c2 + 5956f3b
commit 461f765
Showing 1 changed file with 5 additions and 3 deletions.
diff --git a/src/async_client.cpp b/src/async_client.cpp
@@ -315,9 +315,10 @@ void async_client::remove_token(token* tok)
 
 void async_client::set_callback(callback& cb)
 {
-    guard g(lock_);
-    userCallback_ = &cb;
-
+    {
+        guard g(lock_);
+        userCallback_ = &cb;
+    }
     int rc = MQTTAsync_setConnected(cli_, this, &async_client::on_connected);
 
     if (rc == MQTTASYNC_SUCCESS) {
@@ -330,6 +331,7 @@ void async_client::set_callback(callback& cb)
         MQTTAsync_setConnected(cli_, nullptr, nullptr);
 
     if (rc != MQTTASYNC_SUCCESS) {
+        guard g(lock_);
         userCallback_ = nullptr;
         throw exception(rc);
     }