Messages in this thread Patch in this message | | | Date | Thu, 13 Apr 2023 15:35:44 +0800 | Subject | Re: [PATCH for-next 2/3] RDMA/rtrs: Fix rxe_dealloc_pd warning | From | Guoqing Jiang <> |
| |
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.
>>>>>> | >>>>>> 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?
>>>>>> } >>>>>> >>>>>> Simply, Here we can avoid this warning by introducing conn own flag to >>>>>> track if its cleanup should drop the PD. >>>>>> >>>>>> ----------------------------------------------- >>>>>> rnbd_client L597: Mapping device /dev/nvme0n1 on session client, (access_mode: rw, nr_poll_queues: 0) >>>>>> ------------[ cut here ]------------ >>>>>> WARNING: CPU: 0 PID: 26407 at drivers/infiniband/sw/rxe/rxe_pool.c:256 __rxe_cleanup+0x13a/0x170 [rdma_rxe] >>>>>> Modules linked in: rpcrdma rdma_ucm ib_iser rnbd_client libiscsi rtrs_client scsi_transport_iscsi rtrs_core rdma_cm iw_cm ib_cm crc32_generic rdma_rxe udp_tunnel ib_uverbs ib_core kmem device_dax nd_pmem dax_pmem nd_ >>>>>> vme crc32c_intel fuse nvme_core nfit libnvdimm dm_multipath scsi_dh_rdac scsi_dh_emc scsi_dh_alua dm_mirror dm_region_hash dm_log dm_mod >>>>>> CPU: 0 PID: 26407 Comm: rnbd-client.sh Kdump: loaded Not tainted 6.2.0-rc6-roce-flush+ #53 >>>>>> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.0-0-gd239552ce722-prebuilt.qemu.org 04/01/2014 >>>>>> RIP: 0010:__rxe_cleanup+0x13a/0x170 [rdma_rxe] >>>>>> Code: 45 84 e4 0f 84 5a ff ff ff 48 89 ef e8 5f 18 71 f9 84 c0 75 90 be c8 00 00 00 48 89 ef e8 be 89 1f fa 85 c0 0f 85 7b ff ff ff <0f> 0b 41 bc ea ff ff ff e9 71 ff ff ff e8 84 7f 1f fa e9 d0 fe ff >>>>>> RSP: 0018:ffffb09880b6f5f0 EFLAGS: 00010246 >>>>>> RAX: 0000000000000000 RBX: ffff99401f15d6a8 RCX: 0000000000000000 >>>>>> RDX: 0000000000000001 RSI: ffffffffbac8234b RDI: 00000000ffffffff >>>>>> RBP: ffff99401f15d6d0 R08: 0000000000000001 R09: 0000000000000001 >>>>>> R10: 0000000000002d82 R11: 0000000000000000 R12: 0000000000000001 >>>>>> R13: ffff994101eff208 R14: ffffb09880b6f6a0 R15: 00000000fffffe00 >>>>>> FS: 00007fe113904740(0000) GS:ffff99413bc00000(0000) knlGS:0000000000000000 >>>>>> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 >>>>>> CR2: 00007ff6cde656c8 CR3: 000000001f108004 CR4: 00000000001706f0 >>>>>> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 >>>>>> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 >>>>>> Call Trace: >>>>>> <TASK> >>>>>> rxe_dealloc_pd+0x16/0x20 [rdma_rxe] >>>>>> ib_dealloc_pd_user+0x4b/0x80 [ib_core] >>>>>> rtrs_ib_dev_put+0x79/0xd0 [rtrs_core] >>>>>> destroy_con_cq_qp+0x8a/0xa0 [rtrs_client] >>>>>> init_path+0x1e7/0x9a0 [rtrs_client] >>>>>> ? __pfx_autoremove_wake_function+0x10/0x10 >>>>>> ? lock_is_held_type+0xd7/0x130 >>>>>> ? rcu_read_lock_sched_held+0x43/0x80 >>>>>> ? pcpu_alloc+0x3dd/0x7d0 >>>>>> ? rtrs_clt_init_stats+0x18/0x40 [rtrs_client] >>>>>> rtrs_clt_open+0x24f/0x5a0 [rtrs_client] >>>>>> ? __pfx_rnbd_clt_link_ev+0x10/0x10 [rnbd_client] >>>>>> rnbd_clt_map_device+0x6a5/0xe10 [rnbd_client] >>>>>> >>>>>> Signed-off-by: Li Zhijian <lizhijian@fujitsu.com> >>>>>> --- >>>>>> drivers/infiniband/ulp/rtrs/rtrs-clt.c | 4 ++++ >>>>>> drivers/infiniband/ulp/rtrs/rtrs-clt.h | 1 + >>>>>> 2 files changed, 5 insertions(+) >>>>>> >>>>>> diff --git a/drivers/infiniband/ulp/rtrs/rtrs-clt.c b/drivers/infiniband/ulp/rtrs/rtrs-clt.c >>>>>> index c2065fc33a56..4c8f42e46e2f 100644 >>>>>> --- a/drivers/infiniband/ulp/rtrs/rtrs-clt.c >>>>>> +++ b/drivers/infiniband/ulp/rtrs/rtrs-clt.c >>>>>> @@ -1664,6 +1664,7 @@ static int create_con_cq_qp(struct rtrs_clt_con *con) >>>>>> return -ENOMEM; >>>>>> } >>>>>> clt_path->s.dev_ref = 1; >>>>>> + con->has_dev = true; >>>>>> query_fast_reg_mode(clt_path); >>>>>> wr_limit = clt_path->s.dev->ib_dev->attrs.max_qp_wr; >>>>>> /* >>>>>> @@ -1690,6 +1691,7 @@ static int create_con_cq_qp(struct rtrs_clt_con *con) >>>>>> wr_limit = clt_path->s.dev->ib_dev->attrs.max_qp_wr; >>>>>> /* Shared between connections */ >>>>>> clt_path->s.dev_ref++; >>>>> Without looking in the code, I would expect dev_ref from the line above >>>>> to perform PD protection. >>>> Agreed. >>> Sorry, i didn't get your point. Do you mean something like this: >>> >>> + con->has_dev = true; >>> clt_path->s.dev_ref++; >> No, my point was that clt_path->s.dev_ref > 0 means that has_dev is >> equal to true, and dev_ref is supposed to protect from early PD >> destruction. >> > >> + if (!con->has_dev) >> + return; > We have already done such protection VVVV > >> if (clt_path->s.dev_ref && !--clt_path->s.dev_ref) { <<< each cleanup will decrease clt_path->s.dev_ref >> rtrs_ib_dev_put(clt_path->s.dev); <<< when it becomes to 0, PD will be destructed. >> clt_path->s.dev = NULL; > > But they are not equal, clt_path->s.dev_ref could be shared by multiple connections. > So in the case con[0] successed and con[1] failed(clt_path->s.dev_ref is 1), > the con[1]'s cleanup path(destroy_con_cq_qp) will destroy PD while conn[0] still associates this PD.
Then what is the appropriate time to call destroy_con_cq_qp for this scenario? Otherwise there could be memory leak.
Thanks, Guoqing
| |