Re: [syzbot] [rdma?] INFO: trying to register non-static key in skb_dequeue (2)

[Zhu Yanjun]

On Tue, May 23, 2023 at 1:44 PM Guoqing Jiang <guoqing.jiang@xxxxxxxxx> wrote:
>
>
>
> On 5/23/23 13:18, Zhu Yanjun wrote:
> > On Tue, May 23, 2023 at 1:08 PM Zhu Yanjun <zyjzyj2000@xxxxxxxxx> wrote:
> >> On Tue, May 23, 2023 at 12:29 PM Zhu Yanjun <zyjzyj2000@xxxxxxxxx> wrote:
> >>> On Tue, May 23, 2023 at 12:10 PM Guoqing Jiang <guoqing.jiang@xxxxxxxxx> wrote:
> >>>>
> >>>>
> >>>> On 5/23/23 12:02, Zhu Yanjun wrote:
> >>>>> On Tue, May 23, 2023 at 11:47 AM Zhu Yanjun <zyjzyj2000@xxxxxxxxx> wrote:
> >>>>>> On Tue, May 23, 2023 at 10:26 AM Guoqing Jiang <guoqing.jiang@xxxxxxxxx> wrote:
> >>>>>>>
> >>>>>>> On 5/23/23 10:13, syzbot wrote:
> >>>>>>>> Hello,
> >>>>>>>>
> >>>>>>>> syzbot tried to test the proposed patch but the build/boot failed:
> >>>>>>>>
> >>>>>>>> failed to apply patch:
> >>>>>>>> checking file drivers/infiniband/sw/rxe/rxe_qp.c
> >>>>>>>> patch: **** unexpected end of file in patch
> >>>>>> This is not the root cause. The fix is not good.
> >>>>> This problem is about "INFO: trying to register non-static key. The
> >>>>> code is fine but needs lockdep annotation, or maybe"
> >>> This warning is from "lock is not initialized". This is a
> >>> use-before-initialized problem.
> >>> The correct fix is to initialize the lock that is complained before it is used.
> >>>
> >>> Zhu Yanjun
> >> Based on the call trace, the followings are the order of this call trace.
> >>
> >> 291 /* called by the create qp verb */
> >> 292 int rxe_qp_from_init(struct rxe_dev *rxe, struct rxe_qp *qp,
> >> struct rxe_pd *pd,
> >> 297 {
> >>              ...
> >> 317         rxe_qp_init_misc(rxe, qp, init);
> >>              ...
> >> 322
> >> 323         err = rxe_qp_init_resp(rxe, qp, init, udata, uresp);
> >> 324         if (err)
> >> 325                 goto err2;   <--- error
> >>
> >>              ...
> >>
> >> 334 err2:
> >> 335         rxe_queue_cleanup(qp->sq.queue); <--- Goto here
> >> 336         qp->sq.queue = NULL;
> >>
> >> In rxe_qp_init_resp, the error occurs before skb_queue_head_init.
> >> So this call trace appeared.
> > 250 static int rxe_qp_init_resp(struct rxe_dev *rxe, struct rxe_qp *qp,
> > 254 {
> >                          ...
> > 264
> > 265                 type = QUEUE_TYPE_FROM_CLIENT;
> > 266                 qp->rq.queue = rxe_queue_init(rxe, &qp->rq.max_wr,
> > 267                                         wqe_size, type);
> > 268                 if (!qp->rq.queue)
> > 269                         return -ENOMEM;    <---Error here
> > 270
> >
> > ...
> >
> > 282         skb_queue_head_init(&qp->resp_pkts); <-this is not called.
> > ...
> > This will make spin_lock of resp_pkts is used before initialized.
>
> IMHO, the above is same as
>
> > Which is caused by  "skb_queue_head_init(&qp->resp_pkts)" is not called
> > given rxe_qp_init_resp returns error, but the cleanup still trigger the
> > chain.
> >
> > rxe_qp_do_cleanup -> rxe_completer -> drain_resp_pkts ->
> > skb_dequeue(&qp->resp_pkts)
>
> my previous analysis. If not, could you provide another better way to
> fix it?

Move the initialization to the beginning. This can fix this problem.
See below:

"
diff --git a/drivers/infiniband/sw/rxe/rxe_qp.c
b/drivers/infiniband/sw/rxe/rxe_qp.c
index c5451a4488ca..22ef6188d7b1 100644
--- a/drivers/infiniband/sw/rxe/rxe_qp.c
+++ b/drivers/infiniband/sw/rxe/rxe_qp.c
@@ -176,6 +176,9 @@ static void rxe_qp_init_misc(struct rxe_dev *rxe,
struct rxe_qp *qp,
        spin_lock_init(&qp->rq.producer_lock);
        spin_lock_init(&qp->rq.consumer_lock);

+       skb_queue_head_init(&qp->req_pkts);
+       skb_queue_head_init(&qp->resp_pkts);
+
        atomic_set(&qp->ssn, 0);
        atomic_set(&qp->skb_out, 0);
 }
@@ -234,8 +237,6 @@ static int rxe_qp_init_req(struct rxe_dev *rxe,
struct rxe_qp *qp,
        qp->req.opcode          = -1;
        qp->comp.opcode         = -1;

-       skb_queue_head_init(&qp->req_pkts);
-
        rxe_init_task(&qp->req.task, qp, rxe_requester);
        rxe_init_task(&qp->comp.task, qp, rxe_completer);

@@ -279,8 +280,6 @@ static int rxe_qp_init_resp(struct rxe_dev *rxe,
struct rxe_qp *qp,
                }
        }

-       skb_queue_head_init(&qp->resp_pkts);
-
        rxe_init_task(&qp->resp.task, qp, rxe_responder);

        qp->resp.opcode         = OPCODE_NONE;
"

>
> Guoqing