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From:   Jinpu Wang <jinpu.wang@ionos.com>
Date:   Thu, 1 Jun 2023 21:17:12 +0200
Message-ID: <CAMGffEkttF77x3upyb2FO28FHod7-V81rZAn2N0uQ6uxCDWWwA@mail.gmail.com>
Subject: Re: [PATCH for-next v3 3/3] RDMA/rtrs: Fix rxe_dealloc_pd warning
To:     Jason Gunthorpe <jgg@nvidia.com>
Cc:     Li Zhijian <lizhijian@fujitsu.com>, haris.iqbal@ionos.com,
        linux-rdma@vger.kernel.org, leon@kernel.org,
        guoqing.jiang@linux.dev, linux-kernel@vger.kernel.org
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On Thu, Jun 1, 2023 at 7:33=E2=80=AFPM Jason Gunthorpe <jgg@nvidia.com> wro=
te:
>
> On Tue, Apr 25, 2023 at 01:02:43AM +0000, Li Zhijian wrote:
> > In current design:
> > 1. PD and clt_path->s.dev are shared among connections.
> > 2. every con[n]'s cleanup phase will call destroy_con_cq_qp()
> > 3. clt_path->s.dev will be always decreased in destroy_con_cq_qp(), and
> >    when clt_path->s.dev become zero, it will destroy PD.
> > 4. when con[1] failed to create, con[1] will not take clt_path->s.dev,
> >    but it try to decreased clt_path->s.dev
> >
> > So, in case create_cm(con[0]) succeeds but create_cm(con[1])
> > fails, destroy_con_cq_qp(con[1]) will be called first which will destor=
y
> > the PD while this PD is still taken by con[0].
> >
> > Here, we refactor the error path of create_cm() and init_conns(), so th=
at
> > we do the cleanup in the order they are created.
> >
> > The warning occurs when destroying RXE PD whose reference count is not
> > zero.
> > -----------------------------------------------
> >  rnbd_client L597: Mapping device /dev/nvme0n1 on session client, (acce=
ss_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 rdm=
a_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_rda=
c 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 b=
e 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:0000000000=
000000
> >  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>
> > Acked-by: Jack Wang <jinpu.wang@ionos.com>
> > Tested-by: Jack Wang <jinpu.wang@ionos.com>
>
> It would be good to have a fixes line for this?
It should be:
 Fixes: 6a98d71daea1 ("RDMA/rtrs: client: main functionality")

Could you amend it  to the commit?
>
> Jason
Thx!