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

[Zhu Yanjun]

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.

Zhu Yanjun
>
> Zhu Yanjun
>
> > >
> > > 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)
> > >
> > > But I might misunderstood it ...
> > >
> > > Thanks,
> > > Guoqing