diff --git a/sql/my_apc.cc b/sql/my_apc.cc
index e0feabab8e2..5a4d2b653ec 100644
--- a/sql/my_apc.cc
+++ b/sql/my_apc.cc
@@ -197,13 +197,16 @@ bool Apc_target::make_apc_call(THD *caller_thd, Apc_call *call,
   This should be called periodically by the APC target thread.
 */
 
-void Apc_target::process_apc_requests()
+void Apc_target::process_apc_requests(bool force)
 {
   while (1)
   {
     Call_request *request;
- 
-    mysql_mutex_lock(LOCK_thd_kill_ptr);
+
+    if (force)
+      mysql_mutex_lock(LOCK_thd_kill_ptr);
+    else if (mysql_mutex_trylock(LOCK_thd_kill_ptr))
+      break;                              // Mutex is blocked, try again later
     if (!(request= get_first_in_queue()))
     {
       /* No requests in the queue */
diff --git a/sql/my_apc.h b/sql/my_apc.h
index 2c0a9ade314..29fa3172a12 100644
--- a/sql/my_apc.h
+++ b/sql/my_apc.h
@@ -70,10 +70,10 @@ public:
     bool process= !--enabled && have_apc_requests();
     mysql_mutex_unlock(LOCK_thd_kill_ptr);
     if (unlikely(process))
-      process_apc_requests();
+      process_apc_requests(true);
   }
 
-  void process_apc_requests();
+  void process_apc_requests(bool force);
   /* 
     A lightweight function, intended to be used in frequent checks like this:
 
diff --git a/sql/sql_class.cc b/sql/sql_class.cc
index 1b78f88bd3c..70e4ae88e3c 100644
--- a/sql/sql_class.cc
+++ b/sql/sql_class.cc
@@ -4724,7 +4724,7 @@ extern "C" enum thd_kill_levels thd_kill_level(const MYSQL_THD thd)
     if (unlikely(apc_target->have_apc_requests()))
     {
       if (thd == current_thd)
-        apc_target->process_apc_requests();
+        apc_target->process_apc_requests(false);
     }
     return THD_IS_NOT_KILLED;
   }
diff --git a/sql/sql_class.h b/sql/sql_class.h
index 1c7839fc266..611b51ff974 100644
--- a/sql/sql_class.h
+++ b/sql/sql_class.h
@@ -3606,7 +3606,7 @@ public:
       return TRUE;
     }
     if (apc_target.have_apc_requests())
-      apc_target.process_apc_requests(); 
+      apc_target.process_apc_requests(false);
     return FALSE;
   }
 
diff --git a/unittest/sql/my_apc-t.cc b/unittest/sql/my_apc-t.cc
index c08e7281c92..9edb209b1f6 100644
--- a/unittest/sql/my_apc-t.cc
+++ b/unittest/sql/my_apc-t.cc
@@ -100,7 +100,7 @@ void *test_apc_service_thread(void *ptr)
     //apc_target.enable();
     for (int i = 0; i < 10 && !service_should_exit; i++)
     {
-      apc_target.process_apc_requests();
+      apc_target.process_apc_requests(true);
       my_sleep(int_rand(30));
     }
   }