Messages in this thread | ![/](/images/icornerl.gif) | | Date | Fri, 14 Apr 2023 23:58:26 +0800 | Subject | Re: [PATCH for-next 2/3] RDMA/rtrs: Fix rxe_dealloc_pd warning | From | Zhu Yanjun <> |
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在 2023/4/13 21:24, Leon Romanovsky 写道: > On Thu, Apr 13, 2023 at 08:12:15AM +0000, Zhijian Li (Fujitsu) wrote: >> >> >> On 13/04/2023 15:35, Guoqing Jiang wrote: >>> Hi, >>> >>> I take a closer look today. >>> >>> On 4/12/23 09:15, Zhijian Li (Fujitsu) wrote: >>>> >>>> On 11/04/2023 20:26, Leon Romanovsky wrote: >>>>> On Tue, Apr 11, 2023 at 02:43:46AM +0000, Zhijian Li (Fujitsu) wrote: >>>>>> >>>>>> On 10/04/2023 21:10, Guoqing Jiang wrote: >>>>>>> >>>>>>> On 4/10/23 20:08, Leon Romanovsky wrote: >>>>>>>> On Mon, Apr 10, 2023 at 06:43:03AM +0000, Li Zhijian wrote: >>>>>>>>> The warning occurs when destroying PD whose reference count is not zero. >>>>>>>>> >>>>>>>>> Precodition: clt_path->s.con_num is 2. >>>>>>>>> So 2 cm connection will be created as below: >>>>>>>>> CPU0 CPU1 >>>>>>>>> init_conns { | >>>>>>>>> create_cm() // a. con[0] created | >>>>>>>>> | a'. rtrs_clt_rdma_cm_handler() { >>>>>>>>> | rtrs_rdma_addr_resolved() >>>>>>>>> | create_con_cq_qp(con); << con[0] >>>>>>>>> | } >>>>>>>>> | in this moment, refcnt of PD was increased to 2+ >>> >>> What do you mean "refcnt of PD"? usecnt in struct ib_pd or dev_ref. >> >> I mean usecnt in struct ib_pd >> >> >> >>> >>>>>>>>> | >>>>>>>>> create_cm() // b. cid = 1, failed | >>>>>>>>> destroy_con_cq_qp() | >>>>>>>>> rtrs_ib_dev_put() | >>>>>>>>> dev_free() | >>>>>>>>> ib_dealloc_pd(dev->ib_pd) << PD | >>>>>>>>> is destroyed, but refcnt is | >>>>>>>>> still greater than 0 | >>> >>> Assuming you mean "pd->usecnt". We only allocate pd in con[0] by rtrs_ib_dev_find_or_add, >>> if con[1] failed to create cm, then alloc_path_reqs -> ib_alloc_mr -> atomic_inc(&pd->usecnt) >>> can't be triggered. Is there other places could increase the refcnt? >> >> >> Yes, when create a qp, it will also associate to this PD, that also mean refcnt of PD will be increased. >> >> When con[0](create_con_cq_qp) succeeded, refcnt of PD will be 2. and then when con[1] failed, since >> QP didn't create, refcnt of PD is still 2. con[1]'s cleanup will destroy the PD(ib_dealloc_pd) since dev_ref = 1, after that its >> refcnt is still 1. > > Why is refcnt 1 in con[1] destruction phase? It seems to me like a bug. Agree. We should find out why refcnt 1 and fix this problem.
Zhu Yanjun > > Thanks
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