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From:   Jinpu Wang <jinpu.wang@ionos.com>
Date:   Mon, 24 Apr 2023 06:33:43 +0200
Message-ID: <CAMGffE=M+DKumLvj=pyebxjDg3Ot+h5BGkcqxyJPiYu0C_6KHQ@mail.gmail.com>
Subject: Re: [PATCH for-next v2 3/3] RDMA/rtrs: Fix rxe_dealloc_pd warning
To:     "Zhijian Li (Fujitsu)" <lizhijian@fujitsu.com>
Cc:     Guoqing Jiang <guoqing.jiang@linux.dev>,
        "haris.iqbal@ionos.com" <haris.iqbal@ionos.com>,
        "jgg@ziepe.ca" <jgg@ziepe.ca>, "leon@kernel.org" <leon@kernel.org>,
        "linux-rdma@vger.kernel.org" <linux-rdma@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
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On Sun, Apr 23, 2023 at 9:29=E2=80=AFAM Zhijian Li (Fujitsu)
<lizhijian@fujitsu.com> wrote:
>
>
>
> On 23/04/2023 11:08, Guoqing Jiang wrote:
> >
> >
> > On 4/23/23 09:26, 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(), an=
d
> >>     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 desto=
ry
> >> the PD while this PD is still taken by con[0].
> >>
> >> Here, we refactor the error path of create_cm() and init_conns(), so t=
hat
> >> 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, (ac=
cess_mode: rw, nr_poll_queues: 0)
> >>   ------------[ cut here ]------------
> >>   WARNING: CPU: 0 PID: 26407 at drivers/infiniband/sw/rxe/rxe_pool.c:2=
56 __rxe_cleanup+0x13a/0x170 [rdma_rxe]
> >>   Modules linked in: rpcrdma rdma_ucm ib_iser rnbd_client libiscsi rtr=
s_client scsi_transport_iscsi rtrs_core rdma_cm iw_cm ib_cm crc32_generic r=
dma_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_rd=
ac 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:00000000=
00000000
> >>   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>
> >> ---
> >> V2: refactor error path instead of introducing a new flag #Leon
> >> ---
> >>   drivers/infiniband/ulp/rtrs/rtrs-clt.c | 55 +++++++++++-------------=
--
> >>   1 file changed, 23 insertions(+), 32 deletions(-)
> >>
> >> diff --git a/drivers/infiniband/ulp/rtrs/rtrs-clt.c b/drivers/infiniba=
nd/ulp/rtrs/rtrs-clt.c
> >> index c2065fc33a56..5234be5c6bf8 100644
> >> --- a/drivers/infiniband/ulp/rtrs/rtrs-clt.c
> >> +++ b/drivers/infiniband/ulp/rtrs/rtrs-clt.c
> >> @@ -2039,6 +2039,7 @@ static int rtrs_clt_rdma_cm_handler(struct rdma_=
cm_id *cm_id,
> >>       return 0;
> >>   }
> >> +/* The caller should the do the cleanup in case of error */
> >
> > Remove the first 'the' from above sentence.
>
> Good catch.
>
>
> >
> >>   static int create_cm(struct rtrs_clt_con *con)
> >>   {
> >>       struct rtrs_path *s =3D con->c.path;
> >> @@ -2061,14 +2062,14 @@ static int create_cm(struct rtrs_clt_con *con)
> >>       err =3D rdma_set_reuseaddr(cm_id, 1);
> >>       if (err !=3D 0) {
> >>           rtrs_err(s, "Set address reuse failed, err: %d\n", err);
> >> -        goto destroy_cm;
> >> +        return err;
> >>       }
> >>       err =3D rdma_resolve_addr(cm_id, (struct sockaddr *)&clt_path->s=
.src_addr,
> >>                   (struct sockaddr *)&clt_path->s.dst_addr,
> >>                   RTRS_CONNECT_TIMEOUT_MS);
> >>       if (err) {
> >>           rtrs_err(s, "Failed to resolve address, err: %d\n", err);
> >> -        goto destroy_cm;
> >> +        return err;
> >>       }
> >>       /*
> >>        * Combine connection status and session events. This is needed
> >> @@ -2083,29 +2084,15 @@ static int create_cm(struct rtrs_clt_con *con)
> >>           if (err =3D=3D 0)
> >>               err =3D -ETIMEDOUT;
> >>           /* Timedout or interrupted */
> >> -        goto errr;
> >> -    }
> >> -    if (con->cm_err < 0) {
> >> -        err =3D con->cm_err;
> >> -        goto errr;
> >> +        return err;
> >>       }
> >> -    if (READ_ONCE(clt_path->state) !=3D RTRS_CLT_CONNECTING) {
> >> +    if (con->cm_err < 0)
> >> +        return con->cm_err;
> >> +    if (READ_ONCE(clt_path->state) !=3D RTRS_CLT_CONNECTING)
> >>           /* Device removal */
> >> -        err =3D -ECONNABORTED;
> >> -        goto errr;
> >> -    }
> >> +        return -ECONNABORTED;
> >>       return 0;
> >> -
> >> -errr:
> >> -    stop_cm(con);
> >> -    mutex_lock(&con->con_mutex);
> >> -    destroy_con_cq_qp(con);
> >> -    mutex_unlock(&con->con_mutex);
> >> -destroy_cm:
> >> -    destroy_cm(con);
> >> -
> >> -    return err;
> >>   }
> >>   static void rtrs_clt_path_up(struct rtrs_clt_path *clt_path)
> >> @@ -2333,7 +2320,7 @@ static void rtrs_clt_close_work(struct work_stru=
ct *work)
> >>   static int init_conns(struct rtrs_clt_path *clt_path)
> >>   {
> >>       unsigned int cid;
> >> -    int err;
> >> +    int err, i;
> >>       /*
> >>        * On every new session connections increase reconnect counter
> >> @@ -2349,10 +2336,8 @@ static int init_conns(struct rtrs_clt_path *clt=
_path)
> >>               goto destroy;
> >>           err =3D create_cm(to_clt_con(clt_path->s.con[cid]));
> >> -        if (err) {
> >> -            destroy_con(to_clt_con(clt_path->s.con[cid]));
> >> +        if (err)
> >>               goto destroy;
> >> -        }
> >>       }
> >>       err =3D alloc_path_reqs(clt_path);
> >>       if (err)
> >> @@ -2363,15 +2348,21 @@ static int init_conns(struct rtrs_clt_path *cl=
t_path)
> >>       return 0;
> >>   destroy:
> >> -    while (cid--) {
> >> -        struct rtrs_clt_con *con =3D to_clt_con(clt_path->s.con[cid])=
;
> >> +    /* Make sure we do the cleanup in the order they are created */
> >> +    for (i =3D 0; i <=3D cid; i++) {
> >> +        struct rtrs_clt_con *con;
> >> -        stop_cm(con);
> >> +        if (!clt_path->s.con[i])
> >> +            break;
> >> -        mutex_lock(&con->con_mutex);
> >> -        destroy_con_cq_qp(con);
> >> -        mutex_unlock(&con->con_mutex);
> >> -        destroy_cm(con);
> >> +        con =3D to_clt_con(clt_path->s.con[i]);
> >> +        if (con->c.cm_id) {
> >> +            stop_cm(con);
> >> +            mutex_lock(&con->con_mutex);
> >> +            destroy_con_cq_qp(con);
> >> +            mutex_unlock(&con->con_mutex);
> >> +            destroy_cm(con);
> >> +        }
> >>           destroy_con(con);
> >>       }
> >
> > Can we factor out a function for above? Then rtrs_clt_stop_and_destroy_=
conns
> > might reuse it as well.
>
> I'm open to this. but they are a bit difference IMHO.
we can do the refactor later after bugfix.

Thx
>
>
>
> >
> > Thanks,
> > Guoqing