RDMA/rxe: Fix the error "trying to register non-static key in rxe_cleanup_task"

In the function rxe_create_qp(), rxe_qp_from_init() is called to
initialize qp, internally things like rxe_init_task are not setup until
rxe_qp_init_req().

If an error occurred before this point then the unwind will call
rxe_cleanup() and eventually to rxe_qp_do_cleanup()/rxe_cleanup_task()
which will oops when trying to access the uninitialized spinlock.

If rxe_init_task is not executed, rxe_cleanup_task will not be called.

Reported-by: syzbot+cfcc1a3c85be15a40cba@syzkaller.appspotmail.com
Link: https://syzkaller.appspot.com/bug?id=fd85757b74b3eb59f904138486f755f71e090df8
Fixes: 8700e3e7 ("Soft RoCE driver")
Fixes: 2d4b21e0 ("IB/rxe: Prevent from completer to operate on non valid QP")
Signed-off-by: Zhu Yanjun <yanjun.zhu@linux.dev>
Link: https://lore.kernel.org/r/20230413101115.1366068-1-yanjun.zhu@intel.comSigned-off-by: Leon Romanovsky <leon@kernel.org>

drivers/infiniband/sw/rxe/rxe_qp.c

@@ -761,9 +761,14 @@ static void rxe_qp_do_cleanup(struct work_struct *work)
 		del_timer_sync(&qp->rnr_nak_timer);
 	}
 
-	rxe_cleanup_task(&qp->resp.task);
-	rxe_cleanup_task(&qp->req.task);
-	rxe_cleanup_task(&qp->comp.task);
+	if (qp->resp.task.func)
+		rxe_cleanup_task(&qp->resp.task);
+
+	if (qp->req.task.func)
+		rxe_cleanup_task(&qp->req.task);
+
+	if (qp->comp.task.func)
+		rxe_cleanup_task(&qp->comp.task);
 
 	/* flush out any receive wr's or pending requests */
 	rxe_requester(qp);