> When destroy_workqueue if rescuer worker exist,wq->rescuer pointer be > kfree. if sanity checks passed. the func call_rcu(&wq->rcu, rcu_free_wq) > will be called if the wq->flags & WQ_UNBOUND is false,in rcu_free_wq > func wq->rescuer pointer was kfree again. 1. I suggest to improve also this change description. Do you try to explain here that a call of the function “free_workqueue_attrs” (or “free_percpu”) would perform sufficient clean-up of system resources in this use case? 2. You proposed to delete the function call “kfree(wq->rescuer)” from the implementation of the function “rcu_free_wq”. https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/tree/kernel/workqueue.c?id=c11d28ab4a691736e30b49813fb801847bd44e83#n3482 https://elixir.bootlin.com/linux/v5.7-rc6/source/kernel/workqueue.c#L3482 This function name should be specified also in the patch subject, shouldn't it? 3. Would you like to add the tag “Fixes” to the commit message? Regards, Markus