diff --git a/Source/Shared/arcana/threading/blocking_concurrent_queue.h b/Source/Shared/arcana/threading/blocking_concurrent_queue.h
index 24d5276..15eda2d 100644
--- a/Source/Shared/arcana/threading/blocking_concurrent_queue.h
+++ b/Source/Shared/arcana/threading/blocking_concurrent_queue.h
@@ -21,7 +21,20 @@ namespace arcana
     {
         namespace detail
         {
+            inline std::mutex callbackMutex;
             inline std::function<void()> beforeWaitCallback{[]() {}};
+
+            // Copy the callback under the lock and invoke after releasing, avoiding
+            // potential deadlocks if the callback interacts with other locks.
+            inline void invoke_before_wait_callback()
+            {
+                std::function<void()> cb;
+                {
+                    std::lock_guard<std::mutex> lock{callbackMutex};
+                    cb = beforeWaitCallback;
+                }
+                cb();
+            }
         }
 
         // Set a callback to be invoked while holding the queue mutex, right before
@@ -29,6 +42,7 @@ namespace arcana
         // lost-wakeup race conditions. Pass an empty lambda [](){} to reset.
         inline void set_before_wait_callback(std::function<void()> callback)
         {
+            std::lock_guard<std::mutex> lock{detail::callbackMutex};
             detail::beforeWaitCallback = std::move(callback);
         }
     }
@@ -121,7 +135,7 @@ namespace arcana
                 while (!cancel.cancelled() && m_data.empty())
                 {
 #ifdef ARCANA_TEST_HOOKS
-                    test_hooks::blocking_concurrent_queue::detail::beforeWaitCallback();
+                    test_hooks::blocking_concurrent_queue::detail::invoke_before_wait_callback();
 #endif
                     m_dataReady.wait(lock);
                 }
@@ -145,7 +159,7 @@ namespace arcana
                 while (!cancel.cancelled() && m_data.empty())
                 {
 #ifdef ARCANA_TEST_HOOKS
-                    test_hooks::blocking_concurrent_queue::detail::beforeWaitCallback();
+                    test_hooks::blocking_concurrent_queue::detail::invoke_before_wait_callback();
 #endif
                     m_dataReady.wait(lock);
                 }