> The callback function "rcu_free_wq" could be called after memory > was released for "rescuer" already, Thus delete a misplaced call > of the function "kfree". I got into the mood to follow your interpretation of the software situation for a moment. I have taken another look also at the implementation of the function “destroy_workqueue”. * The function call “kfree(rescuer)” can be performed there in an if branch after the statement “wq->rescuer = NULL” was executed. * This data processing is independent from a possible call of the function “call_rcu(&wq->rcu, rcu_free_wq)” in another if branch. Thus it seems that a null pointer is intentionally passed by a data structure member to this callback function on demand. The corresponding call of the function “kfree” can tolerate this special case. Now I find that the proposed change can be inappropriate. I'm sorry for undesirable confusion because of this patch review. Regards, Markus