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Message-ID: <5b6b8431-92c7-62df-299b-28f3a5f61d5f@linux.dev>
Date:   Tue, 23 May 2023 13:44:06 +0800
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Subject: Re: [syzbot] [rdma?] INFO: trying to register non-static key in
 skb_dequeue (2)
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To:     Zhu Yanjun <zyjzyj2000@gmail.com>
Cc:     syzbot <syzbot+eba589d8f49c73d356da@syzkaller.appspotmail.com>,
        jgg@ziepe.ca, leon@kernel.org, linux-kernel@vger.kernel.org,
        linux-rdma@vger.kernel.org, netdev@vger.kernel.org,
        syzkaller-bugs@googlegroups.com
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From:   Guoqing Jiang <guoqing.jiang@linux.dev>
In-Reply-To: <CAD=hENda4MxgEsgT-GUhYHH66m79wi8yxBQS8CYnxc_DsQKGwg@mail.gmail.com>
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On 5/23/23 13:18, Zhu Yanjun wrote:
> On Tue, May 23, 2023 at 1:08 PM Zhu Yanjun <zyjzyj2000@gmail.com> wrote:
>> On Tue, May 23, 2023 at 12:29 PM Zhu Yanjun <zyjzyj2000@gmail.com> wrote:
>>> On Tue, May 23, 2023 at 12:10 PM Guoqing Jiang <guoqing.jiang@linux.dev> wrote:
>>>>
>>>>
>>>> On 5/23/23 12:02, Zhu Yanjun wrote:
>>>>> On Tue, May 23, 2023 at 11:47 AM Zhu Yanjun <zyjzyj2000@gmail.com> wrote:
>>>>>> On Tue, May 23, 2023 at 10:26 AM Guoqing Jiang <guoqing.jiang@linux.dev> 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?

Guoqing