Re: [PATCH for-next v2 3/3] RDMA/rtrs: Fix rxe_dealloc_pd warning

[Zhijian Li (Fujitsu)]

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(), 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 destory
>> the PD while this PD is still taken by con[0].
>>
>> Here, we refactor the error path of create_cm() and init_conns(), so that
>> 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, (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@xxxxxxxxxxx>
>> ---
>> 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/infiniband/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 = con->c.path;
>> @@ -2061,14 +2062,14 @@ static int create_cm(struct rtrs_clt_con *con)
>>       err = rdma_set_reuseaddr(cm_id, 1);
>>       if (err != 0) {
>>           rtrs_err(s, "Set address reuse failed, err: %d\n", err);
>> -        goto destroy_cm;
>> +        return err;
>>       }
>>       err = 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 == 0)
>>               err = -ETIMEDOUT;
>>           /* Timedout or interrupted */
>> -        goto errr;
>> -    }
>> -    if (con->cm_err < 0) {
>> -        err = con->cm_err;
>> -        goto errr;
>> +        return err;
>>       }
>> -    if (READ_ONCE(clt_path->state) != RTRS_CLT_CONNECTING) {
>> +    if (con->cm_err < 0)
>> +        return con->cm_err;
>> +    if (READ_ONCE(clt_path->state) != RTRS_CLT_CONNECTING)
>>           /* Device removal */
>> -        err = -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_struct *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 = 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 = alloc_path_reqs(clt_path);
>>       if (err)
>> @@ -2363,15 +2348,21 @@ static int init_conns(struct rtrs_clt_path *clt_path)
>>       return 0;
>>   destroy:
>> -    while (cid--) {
>> -        struct rtrs_clt_con *con = to_clt_con(clt_path->s.con[cid]);
>> +    /* Make sure we do the cleanup in the order they are created */
>> +    for (i = 0; i <= 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 = 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.



> 
> Thanks,
> Guoqing