io_uring/io-wq: free worker if task_work creation is canceled

If we cancel the task_work, the worker will never come into existance.
As this is the last reference to it, ensure that we get it freed
appropriately.

Cc: [email protected]
Reported-by: 진호 <[email protected]>
Signed-off-by: Jens Axboe <[email protected]>

Author: axboe

io_uring/io-wq.c

@@ -1230,6 +1230,7 @@ static void io_wq_cancel_tw_create(struct io_wq *wq)
 
 		worker = container_of(cb, struct io_worker, create_work);
 		io_worker_cancel_cb(worker);
+		kfree(worker);
 	}
 }