Re: Panic when rebooting target server testing srp on 5.0.0-rc2

[Ming Lei <tom.leiming@gmail.com>]

On Tue, Mar 26, 2019 at 11:17 PM Laurence Oberman <loberman@redhat.com> wrote:
>
> On Thu, 2019-03-21 at 08:44 -0400, Laurence Oberman wrote:
> > On Wed, 2019-03-20 at 16:35 -0400, Laurence Oberman wrote:
> > > On Wed, 2019-03-20 at 13:28 -0700, Bart Van Assche wrote:
> > > > On Wed, 2019-03-20 at 11:11 -0400, Laurence Oberman wrote:
> > > > > On Wed, 2019-03-20 at 09:45 -0400, Laurence Oberman wrote:
> > > > > > Hello Bart, I hope all is well with you.
> > > > > >
> > > > > > Quick question
> > > > > > preparing to test v5.1-rc2 SRP, my usual method is first
> > > > > > validate
> > > > > > the
> > > > > > prior kernel I had in place.
> > > > > > This had passed tests previously (5.0.0-rc2) but I had not
> > > > > > run
> > > > > > the
> > > > > > target server reboot test, just the disconnect tests.
> > > > > >
> > > > > > Today with mapped SRP devices I rebooted the target server
> > > > > > and
> > > > > > the
> > > > > > client panicked.
> > > > > >
> > > > > > Its been a while and I have been so busy that have not kept
> > > > > > up
> > > > > > with
> > > > > > all
> > > > > > the fixes. Is this a known issue.
> > > > > >
> > > > > > Thanks
> > > > > > Laurence
> > > > > >
> > > > > > 5414228.917507] scsi host2: ib_srp: Path record query failed:
> > > > > > sgid
> > > > > > fe80:0000:0000:0000:7cfe:9003:0072:6ed3, dgid
> > > > > > fe80:0000:0000:0000:7cfe:9003:0072:6e4f, pkey 0xffff,
> > > > > > service_id
> > > > > > 0x7cfe900300726e4e
> > > > > > [5414229.014355] scsi host2: reconnect attempt 7 failed (-
> > > > > > 110)
> > > > > > [5414239.318161] scsi host2: ib_srp: Sending CM DREQ failed
> > > > > > [5414239.318165] scsi host2: ib_srp: Sending CM DREQ failed
> > > > > > [5414239.318167] scsi host2: ib_srp: Sending CM DREQ failed
> > > > > > [5414239.318168] scsi host2: ib_srp: Sending CM DREQ failed
> > > > > > [5414239.318170] scsi host2: ib_srp: Sending CM DREQ failed
> > > > > > [5414239.318172] scsi host2: ib_srp: Sending CM DREQ failed
> > > > > > [5414239.318173] scsi host2: ib_srp: Sending CM DREQ failed
> > > > > > [5414239.318175] scsi host2: ib_srp: Sending CM DREQ failed
> > > > > > [5414243.670072] scsi host2: ib_srp: Got failed path rec
> > > > > > status
> > > > > > -110
> > > > > > [5414243.702179] scsi host2: ib_srp: Path record query
> > > > > > failed:
> > > > > > sgid
> > > > > > fe80:0000:0000:0000:7cfe:9003:0072:6ed3, dgid
> > > > > > fe80:0000:0000:0000:7cfe:9003:0072:6e4f, pkey 0xffff,
> > > > > > service_id
> > > > > > 0x7cfe900300726e4e
> > > > > > [5414243.799313] scsi host2: reconnect attempt 8 failed (-
> > > > > > 110)
> > > > > > [5414247.510115] scsi host1: ib_srp: Sending CM REQ failed
> > > > > > [5414247.510140] scsi host1: reconnect attempt 1 failed (-
> > > > > > 104)
> > > > > > [5414247.849078] BUG: unable to handle kernel NULL pointer
> > > > > > dereference
> > > > > > at 00000000000000b8
> > > > > > [5414247.893793] #PF error: [normal kernel read fault]
> > > > > > [5414247.921839] PGD 0 P4D 0
> > > > > > [5414247.937280] Oops: 0000 [#1] SMP PTI
> > > > > > [5414247.958332] CPU: 4 PID: 7773 Comm: kworker/4:1H Kdump:
> > > > > > loaded
> > > > > > Tainted: G          I       5.0.0-rc2+ #2
> > > > > > [5414248.012856] Hardware name: HP ProLiant DL380 G7, BIOS
> > > > > > P67
> > > > > > 08/16/2015
> > > > > > [5414248.026174] device-mapper: multipath: Failing path 8:48.
> > > > > >
> > > > > >
> > > > > > [5414248.050003] Workqueue: kblockd blk_mq_run_work_fn
> > > > > > [5414248.108378] RIP: 0010:blk_mq_dispatch_rq_list+0xc9/0x590
> > > > > > [5414248.139724] Code: 0f 85 c2 04 00 00 83 44 24 28 01 48 8b
> > > > > > 45
> > > > > > 00
> > > > > > 48
> > > > > > 39 c5 0f 84 ea 00 00 00 48 8b 5d 00 80 3c 24 00 4c 8d 6b b8
> > > > > > 4c
> > > > > > 8b
> > > > > > 63
> > > > > > c8
> > > > > > 75 25 <49> 8b 84 24 b8 00 00 00 48 8b 40 40 48 8b 40 10 48 85
> > > > > > c0
> > > > > > 74
> > > > > > 10
> > > > > > 4c
> > > > > > [5414248.246176] RSP: 0018:ffffb1cd8760fd90 EFLAGS: 00010246
> > > > > > [5414248.275599] RAX: ffffa049d67a1308 RBX: ffffa049d67a1308
> > > > > > RCX:
> > > > > > 0000000000000004
> > > > > > [5414248.316090] RDX: 0000000000000000 RSI: ffffb1cd8760fe20
> > > > > > RDI:
> > > > > > ffffa0552ca08000
> > > > > > [5414248.356884] RBP: ffffb1cd8760fe20 R08: 0000000000000000
> > > > > > R09:
> > > > > > 8080808080808080
> > > > > > [5414248.397632] R10: 0000000000000001 R11: 0000000000000001
> > > > > > R12:
> > > > > > 0000000000000000
> > > > > > [5414248.439323] R13: ffffa049d67a12c0 R14: 0000000000000000
> > > > > > R15:
> > > > > > ffffa0552ca08000
> > > > > > [5414248.481743] FS:  0000000000000000(0000)
> > > > > > GS:ffffa04a37880000(0000)
> > > > > > knlGS:0000000000000000
> > > > > > [5414248.528310] CS:  0010 DS: 0000 ES: 0000 CR0:
> > > > > > 0000000080050033
> > > > > > [5414248.561779] CR2: 00000000000000b8 CR3: 0000000e9d40e004
> > > > > > CR4:
> > > > > > 00000000000206e0
> > > > > > [5414248.602420] Call Trace:
> > > > > > [5414248.616660]  blk_mq_sched_dispatch_requests+0x15c/0x180
> > > > > > [5414248.647066]  __blk_mq_run_hw_queue+0x5f/0xf0
> > > > > > [5414248.672633]  process_one_work+0x171/0x370
> > > > > > [5414248.695443]  worker_thread+0x49/0x3f0
> > > > > > [5414248.716730]  kthread+0xf8/0x130
> > > > > > [5414248.735085]  ? max_active_store+0x80/0x80
> > > > > > [5414248.758569]  ? kthread_bind+0x10/0x10
> > > > > > [5414248.779953]  ret_from_fork+0x35/0x40
> > > > > >
> > > > > > [5414248.801005] Modules linked in: ib_isert iscsi_target_mod
> > > > > > target_core_mod ib_srp rpcrdma scsi_transport_srp rdma_ucm
> > > > > > ib_iser
> > > > > > ib_ipoib ib_umad rdma_cm libiscsi iw_cm scsi_transport_iscsi
> > > > > > ib_cm
> > > > > > sunrpc mlx5_ib ib_uverbs ib_core intel_powerclamp coretemp
> > > > > > kvm_intel
> > > > > > kvm irqbypass ipmi_ssif crct10dif_pclmul crc32_pclmul
> > > > > > ghash_clmulni_intel aesni_intel iTCO_wdt crypto_simd cryptd
> > > > > > gpio_ich
> > > > > > iTCO_vendor_support glue_helper joydev ipmi_si
> > > > > > dm_service_time
> > > > > > pcspkr
> > > > > > ipmi_devintf hpilo hpwdt sg ipmi_msghandler acpi_power_meter
> > > > > > lpc_ich
> > > > > > i7core_edac pcc_cpufreq dm_multipath ip_tables xfs libcrc32c
> > > > > > radeon
> > > > > > sd_mod i2c_algo_bit drm_kms_helper syscopyarea sysfillrect
> > > > > > sysimgblt
> > > > > > fb_sys_fops ttm drm mlx5_core crc32c_intel serio_raw i2c_core
> > > > > > hpsa
> > > > > > bnx2
> > > > > > scsi_transport_sas mlxfw devlink dm_mirror dm_region_hash
> > > > > > dm_log
> > > > > > dm_mod
> > > > > > [5414249.199354] CR2: 00000000000000b8
> > > > > >
> > > > > >
> > > > >
> > > > > Looking at the vmcore
> > > > >
> > > > > PID: 7773   TASK: ffffa04a2c1e2b80  CPU: 4   COMMAND:
> > > > > "kworker/4:1H"
> > > > >  #0 [ffffb1cd8760fab0] machine_kexec at ffffffffaaa6003f
> > > > >  #1 [ffffb1cd8760fb08] __crash_kexec at ffffffffaab373ed
> > > > >  #2 [ffffb1cd8760fbd0] crash_kexec at ffffffffaab385b9
> > > > >  #3 [ffffb1cd8760fbe8] oops_end at ffffffffaaa31931
> > > > >  #4 [ffffb1cd8760fc08] no_context at ffffffffaaa6eb59
> > > > >  #5 [ffffb1cd8760fcb0] do_page_fault at ffffffffaaa6feb2
> > > > >  #6 [ffffb1cd8760fce0] page_fault at ffffffffab2010ee
> > > > >     [exception RIP: blk_mq_dispatch_rq_list+201]
> > > > >     RIP: ffffffffaad90589  RSP: ffffb1cd8760fd90  RFLAGS:
> > > > > 00010246
> > > > >     RAX: ffffa049d67a1308  RBX: ffffa049d67a1308  RCX:
> > > > > 0000000000000004
> > > > >     RDX: 0000000000000000  RSI: ffffb1cd8760fe20  RDI:
> > > > > ffffa0552ca08000
> > > > >     RBP: ffffb1cd8760fe20   R8: 0000000000000000   R9:
> > > > > 8080808080808080
> > > > >     R10: 0000000000000001  R11: 0000000000000001  R12:
> > > > > 0000000000000000
> > > > >     R13: ffffa049d67a12c0  R14: 0000000000000000  R15:
> > > > > ffffa0552ca08000
> > > > >     ORIG_RAX: ffffffffffffffff  CS: 0010  SS: 0018
> > > > >  #7 [ffffb1cd8760fe18] blk_mq_sched_dispatch_requests at
> > > > > ffffffffaad9570c
> > > > >  #8 [ffffb1cd8760fe60] __blk_mq_run_hw_queue at
> > > > > ffffffffaad8de3f
> > > > >  #9 [ffffb1cd8760fe78] process_one_work at ffffffffaaab0ab1
> > > > > #10 [ffffb1cd8760feb8] worker_thread at ffffffffaaab11d9
> > > > > #11 [ffffb1cd8760ff10] kthread at ffffffffaaab6758
> > > > > #12 [ffffb1cd8760ff50] ret_from_fork at ffffffffab200215
> > > > >
> > > > > We were working on this request_queue for
> > > > >  blk_mq_sched_dispatch_requests
> > > > >
> > > > > crash> dev -d | grep ffffa0552ca08000
> > > > >     8
> > > > > ffffa055c81b5800   sdd        ffffa0552ca08000       0     0
> > > > >
> > > > > 0
> > > > > ]
> > > > >
> > > > > That device was no longer accessible
> > > > >
> > > > > sdev_state = SDEV_TRANSPORT_OFFLINE,
> > > > >
> > > > > So it looks like we tried to process a no longer valid list
> > > > > entry
> > > > > in
> > > > > blk_mq_dispatch_rq_list
> > > > >
> > > > > /home/loberman/rpmbuild/BUILD/kernel-5.0.0_rc2+/block/blk-mq.h:
> > > > > 211
> > > > > 0xffffffffaad90589
> > > > > <blk_mq_dispatch_rq_list+201>:       mov    0xb8(%r12),%rax
> > > > >
> > > > > R12 is NULL
> > > > >
> > > > >
> > > > > From
> > > > > static inline bool blk_mq_get_dispatch_budget(struct
> > > > > blk_mq_hw_ctx
> > > > > *hctx)
> > > > > {
> > > > >         struct request_queue *q = hctx->queue;
> > > > >
> > > > >         if (q->mq_ops->get_budget)
> > > > >                 return q->mq_ops->get_budget(hctx);
> > > > >         return true;
> > > > > }
> > > > >
> > > > > Willw ait for a reply befaore i try the newer kernel, but looks
> > > > > like a
> > > > > use after free to me
> > > >
> > > > Hi Laurence,
> > > >
> > > > I don't think that any of the recent SRP initiator changes can be
> > > > the
> > > > root
> > > > cause of this crash. However, significant changes went upstream
> > > > in
> > > > the block
> > > > layer core during the v5.1-rc1 merge window, e.g. multi-page bvec
> > > > support.
> > > > Is it possible for you to bisect this kernel oops?
> > > >
> > > > Thanks,
> > > >
> > > > Bart.
> > > >
> > >
> > > OK, I will see I can reproduce on the fly and I will bisect.
> > > I do agree its not SRP, more likley some block layer race.
> > > I was just able to reproduce it using SRP
> > >
> > > Note that this was on 5.0.0-rc2+, prior to me trying 5.1.
> > >
> > > I usually reboot the target server as part of my test series but
> > > when
> > > I
> > > last tested 5.0.0-rc2+ I only reset the SRP interfaces and had
> > > devices
> > > get rediscovered.
> > >
> > > I did not see it during those tests.
> > >
> > > Back when I have more to share.
> > >
> > > Many Thanks for your time as always
> > > Laurence
> > >
> > >
> >
> > Something crept in, in the block layer causing a use after free
> > 4.19.0-rc1+ does not have the issue, so I will narrow the bisect
> > Thanks
> > Laurence
> >
>
> This took a long time to bisect.
> Repeating the issue seen. We have changes that when the target is
> rebooted with mapped srp devices the client then experiences a ist
> corruption and panic as already shown.
>
> Some stacks
>
> [  222.631998] scsi host1: ib_srp: Path record query failed: sgid
> fe80:0000:0000:0000:7cfe:9003:0072:6ed2, dgid
> fe80:0000:0000:0000:7cfe:9003:0072:6e4e, pkey 0xffff, service_id
> 0x7cfe900300726e4e
> [  222.729639] scsi host1: reconnect attempt 1 failed (-110)
> [  223.176766] fast_io_fail_tmo expired for SRP port-1:1 / host1.
>
> [  223.518759] BUG: unable to handle kernel NULL pointer dereference at
> 00000000000000b8
> [  223.519736] sd 1:0:0:0: rejecting I/O to offline device
> [  223.563769] #PF error: [normal kernel read fault]
> [  223.563770] PGD 0 P4D 0
> [  223.563774] Oops: 0000 [#1] SMP PTI
> [  223.563778] CPU: 3 PID: 9027 Comm: kworker/3:1H Tainted:
> G          I       5.0.0-rc1 #22
> [  223.563779] Hardware name: HP ProLiant DL380 G7, BIOS P67 08/16/2015
> [  223.563787] Workqueue: kblockd blk_mq_run_work_fn
> [  223.593723] device-mapper: multipath: Failing path 8:48.
> [  223.620801] RIP: 0010:blk_mq_dispatch_rq_list+0xc9/0x590
> [  223.635266] print_req_error: I/O error, dev dm-6, sector 8191872
> flags 80700
> [  223.655565] Code: 0f 85 c2 04 00 00 83 44 24 28 01 48 8b 45 00 48 39
> c5 0f 84 ea 00 00 00 48 8b 5d 00 80 3c 24 00 4c 8d 6b b8 4c 8b 63 c8 75
> 25 <49> 8b 84 24 b8 00 00 00 48 8b 40 40 48 8b 40 10 48 85 c0 74 10 4c
> [  223.655566] RSP: 0018:ffffa65b4c43fd90 EFLAGS: 00010246
> [  223.655570] RAX: ffff93ed9bfdbbc8 RBX: ffff93ed9bfdbbc8 RCX:
> 0000000000000004
> [  223.702351] print_req_error: I/O error, dev dm-6, sector 8191872
> flags 0
> [  223.737640] RDX: 0000000000000000 RSI: ffffa65b4c43fe20 RDI:
> ffff93ed9b838000
> [  223.737641] RBP: ffffa65b4c43fe20 R08: 0000000000000000 R09:
> 8080808080808080
> [  223.737642] R10: 0000000000000001 R11: 071c71c71c71c71c R12:
> 0000000000000000
> [  223.737643] R13: ffff93ed9bfdbb80 R14: 0000000000000000 R15:
> ffff93ed9b838000
> [  223.737645] FS:  0000000000000000(0000) GS:ffff93ee33840000(0000)
> knlGS:0000000000000000
> [  223.737646] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> [  223.737646] CR2: 00000000000000b8 CR3: 000000059da0e006 CR4:
> 00000000000206e0
> [  223.737648] Call Trace:
>
> [  223.737657]  blk_mq_sched_dispatch_requests+0x15c/0x180  *** Freed
> already
>
> [  223.737660]  __blk_mq_run_hw_queue+0x5f/0xf0
> [  223.737665]  process_one_work+0x171/0x370
> [  223.737667]  worker_thread+0x49/0x3f0
> [  223.737670]  kthread+0xf8/0x130
> [  223.737673]  ? max_active_store+0x80/0x80
>
> And:
>
> [  643.425005] device-mapper: multipath: Failing path 67:0.
> [  643.696365] ------------[ cut here ]------------
> [  643.722927] list_add corruption. prev->next should be next
> (ffffc8c0c3bd9448), but was ffff93b971965e08. (prev=ffff93b971965e08).
> [  643.787089] WARNING: CPU: 14 PID: 6533 at lib/list_debug.c:28
> __list_add_valid+0x6a/0x70
> [  643.830951] Modules linked in: ib_isert iscsi_target_mod
> target_core_mod ib_srp scsi_transport_srp rpcrdma ib_ipoib ib_umad
> rdma_ucm ib_iser rdma_cm iw_cm libiscsi sunrpc scsi_transport_iscsi
> ib_cm mlx5_ib ib_uverbs ib_core intel_powerclamp coretemp kvm_intel kvm
> irqbypass crct10dif_pclmul crc32_pclmul iTCO_wdt ghash_clmulni_intel
> ipmi_ssif aesni_intel iTCO_vendor_support gpio_ich crypto_simd
> dm_service_time cryptd glue_helper joydev ipmi_si ipmi_devintf pcspkr
> hpilo hpwdt sg ipmi_msghandler acpi_power_meter pcc_cpufreq lpc_ich
> i7core_edac dm_multipath ip_tables xfs libcrc32c radeon sd_mod
> i2c_algo_bit drm_kms_helper syscopyarea sysfillrect sysimgblt
> fb_sys_fops ttm drm crc32c_intel serio_raw mlx5_core i2c_core bnx2 hpsa
> mlxfw scsi_transport_sas dm_mirror dm_region_hash dm_log dm_mod
> [  644.224150] CPU: 14 PID: 6533 Comm: kworker/14:1H Tainted:
> G          I       4.20.0+ #26
> [  644.269637] Hardware name: HP ProLiant DL380 G7, BIOS P67 08/16/2015
> [  644.305110] Workqueue: kblockd blk_mq_run_work_fn
> [  644.330984] RIP: 0010:__list_add_valid+0x6a/0x70
> [  644.357601] Code: 31 c0 48 c7 c7 70 e4 ab b6 e8 22 a6 cc ff 0f 0b 31
> c0 c3 48 89 d1 48 c7 c7 20 e4 ab b6 48 89 f2 48 89 c6 31 c0 e8 06 a6 cc
> ff <0f> 0b 31 c0 c3 90 48 8b 07 48 b9 00 01 00 00 00 00 ad de 48 8b 57
> [  644.462542] RSP: 0018:ffffa8ccc72bfc00 EFLAGS: 00010286
> [  644.491594] RAX: 0000000000000000 RBX: ffff93b971965dc0 RCX:
> 0000000000000000
> [  644.532745] RDX: 0000000000000001 RSI: ffff93b9b79d67b8 RDI:
> ffff93b9b79d67b8
> [  644.573533] RBP: ffffc8c0c3bd9448 R08: 0000000000000000 R09:
> 000000000000072c
> [  644.614180] R10: 0000000000000000 R11: ffffa8ccc72bf968 R12:
> ffff93b96d454c00
> [  644.654683] R13: ffffc8c0c3bd9440 R14: ffff93b971965e08 R15:
> ffff93b971965e08
> [  644.694275] FS:  0000000000000000(0000) GS:ffff93b9b79c0000(0000)
> knlGS:0000000000000000
> [  644.739906] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> [  644.771879] CR2: 00007fd566c10000 CR3: 0000000253e0e002 CR4:
> 00000000000206e0
> [  644.811438] Call Trace:
> [  644.824809]  __blk_mq_insert_request+0x62/0x130
> [  644.849886]  blk_mq_sched_insert_request+0x13c/0x1b0
> [  644.877402]  blk_mq_try_issue_directly+0x105/0x2c0
> [  644.904452]  blk_insert_cloned_request+0x9a/0x130
> [  644.931146]  ? ktime_get+0x37/0x90
> [  644.950545]  dm_mq_queue_rq+0x21c/0x3f0 [dm_mod]
> [  644.977064]  ? blk_mq_get_driver_tag+0xa1/0x120
> [  645.003002]  blk_mq_dispatch_rq_list+0x8e/0x590
> [  645.029812]  ? __switch_to_asm+0x40/0x70
> [  645.052059]  ? __switch_to_asm+0x34/0x70
> [  645.074664]  ? __switch_to_asm+0x40/0x70
> [  645.097111]  ? __switch_to_asm+0x34/0x70
> [  645.119948]  ? __switch_to_asm+0x34/0x70
> [  645.143101]  ? __switch_to_asm+0x40/0x70
> [  645.165273]  ? syscall_return_via_sysret+0x10/0x7f
> [  645.192161]  blk_mq_sched_dispatch_requests+0xe8/0x180
> [  645.221460]  __blk_mq_run_hw_queue+0x5f/0xf0
> [  645.244766]  process_one_work+0x171/0x370
> [  645.267164]  worker_thread+0x49/0x3f0
> [  645.287860]  kthread+0xf8/0x130
> [  645.304894]  ? max_active_store+0x80/0x80
> [  645.327748]  ? kthread_bind+0x10/0x10
> [  645.347898]  ret_from_fork+0x35/0x40
> [  645.368298] ---[ end trace afa70bf68ffb006b ]---
> [  645.397356] ------------[ cut here ]------------
> [  645.423878] list_add corruption. prev->next should be next
> (ffffc8c0c3bd9448), but was ffff93b971965e08. (prev=ffff93b971965e08).
> [  645.488009] WAR
> NING: CPU: 14 PID: 6533 at lib/list_debug.c:28
> __list_add_valid+0x6a/0x70
>
>
> I started just looking at block but nothing made sense so re-ran the
> bisect with the entire kernel.
>
> $ git bisect start
> $ git bisect good v4.20
> $ git bisect bad v5.0-rc1
>
> Bisecting: 5477 revisions left to test after this (roughly 13 steps)
> *** Groan
>
> I got to here and the problem is its an entire merge
>
> [loberman@ibclient linux_torvalds]$ git bisect bad
> 4b9254328254bed12a4ac449cdff2c332e630837 is the first bad commit
> [loberman@ibclient linux_torvalds]$ git show
> 4b9254328254bed12a4ac449cdff2c332e630837
> commit 4b9254328254bed12a4ac449cdff2c332e630837
> Merge: 1a9430d cd19181
> Author: Jens Axboe <axboe@kernel.dk>
> Date:   Tue Dec 18 08:29:53 2018 -0700
>
>     Merge branch 'for-4.21/block' into for-4.21/aio
>
>     * for-4.21/block: (351 commits)
>       blk-mq: enable IO poll if .nr_queues of type poll > 0

You may set 4b9254328254b or 'cd19181bf9ad' as 'git bad' and start the
'git bisect'
again.

thanks,
Ming Lei