From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qk0-f180.google.com ([209.85.220.180]:36465 "EHLO mail-qk0-f180.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751971AbdHIC2R (ORCPT ); Tue, 8 Aug 2017 22:28:17 -0400 Received: by mail-qk0-f180.google.com with SMTP id d136so29321187qkg.3 for ; Tue, 08 Aug 2017 19:28:16 -0700 (PDT) Message-ID: <1502245693.6511.3.camel@redhat.com> Subject: Re: [v4.13-rc BUG] system lockup when running big buffered write(4M) to IB SRP via mpath From: Laurence Oberman To: Ming Lei , dm-devel@redhat.com, linux-scsi , linux-block@vger.kernel.org Cc: "Van Assche, Bart" Date: Tue, 08 Aug 2017 22:28:13 -0400 In-Reply-To: <1502237504.4017.1.camel@redhat.com> References: <20170808141715.GB22763@ming.t460p> <1502237504.4017.1.camel@redhat.com> Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 Sender: linux-block-owner@vger.kernel.org List-Id: linux-block@vger.kernel.org On Tue, 2017-08-08 at 20:11 -0400, Laurence Oberman wrote: > > On Tue, 2017-08-08 at 22:17 +0800, Ming Lei wrote: > > > > Hi Guys, > > > >  > > > > Laurence and I see a system lockup issue when running > > concurrent > > > > big buffered write(4M bytes) to IB SRP on v4.13-rc3. > > > >  > > > > 1 how to reproduce > > > >  > > > > 1) setup IB_SRR & multi path > > > >  > > > >  #./start_opensm.sh > > > >  #./start_srp.sh  > > > >  > > > >  # cat start_opensm.sh  > > > >  #!/bin/bash > > > >  rmmod ib_srpt > > > >  opensm -F opensm.1.conf & > > > >  opensm -F opensm.2.conf & > > > >  > > > >  # cat start_srp.sh > > > >  run_srp_daemon  -f /etc/ddn/srp_daemon.conf -R 30 -T 10 > > -t 7000 > > > > -ance -i mlx5_0 -p 1 1>/root/srp1.log 2>&1 & > > > >  run_srp_daemon  -f /etc/ddn/srp_daemon.conf -R 30 -T 10 > > -t 7000 > > > > -ance -i mlx5_1 -p 1 1>/root/srp2.log 2>&1 & > > > >  > > > >  > > > > 2) run the following test script > > > >  > > > >  #./test-mp.sh > > > >   > > > >  #cat test-mp.sh  > > > >  #!/bin/sh > > > >  DEVS="360014051186d24cc27b4d049ffff94e3 > > > > 36001405b2b5c6c24c084b6fa4d55da2f > > > > 36001405b26ebe76dcb94a489f6f245f8" > > > >  > > > >  for i in $DEVS; do > > > >  for j in `seq 0 15`; do > > > >  ./hammer_write.sh $i 1>/dev/null 2>&1 & > > > >  done > > > >  done > > > >  > > > >  #cat hammer_write.sh > > > >  #!/bin/bash > > > >  while true; do > > > >  dd if=/dev/zero of=/dev/mapper/$1 bs=4096k > > count=800  > > > >  done > > > >  > > > >  > > > > 2 lockup log > > > > [root@ibclient ~]# ./test-mp.sh  > > > > [root@ibclient ~]# [  169.095494] perf: interrupt took too long > > > > (2575 > > > > > > 2500), lowering kernel.perf_event_max_sample_rate to 77000 > > > > > >  > > > > [  178.569124] perf: interrupt took too long (3249 > 3218), > > > > lowering > > > > kernel.perf_event_max_sample_rate to 61000 > > > > [  190.586624] perf: interrupt took too long (4066 > 4061), > > > > lowering > > > > kernel.perf_event_max_sample_rate to 49000 > > > > [  210.381836] perf: interrupt took too long (5083 > 5082), > > > > lowering > > > > kernel.perf_event_max_sample_rate to 39000 > > > > [  240.498659] perf: interrupt took too long (6373 > 6353), > > > > lowering > > > > kernel.perf_event_max_sample_rate to 31000 > > > >  > > > > [root@ibclient ~]#  > > > > [root@ibclient ~]# [  292.252795] perf: interrupt took too long > > > > (8006 > > > > > > 7966), lowering kernel.perf_event_max_sample_rate to 24000 > > > > > >  > > > > [  410.354443] device-mapper: multipath: blk_get_request() > > returned > > > > -11 - requeuing > > > > [  410.432725] device-mapper: multipath: blk_get_request() > > returned > > > > -11 - requeuing > > > > [  410.499530] device-mapper: multipath: blk_get_request() > > returned > > > > -11 - requeuing > > > > [  410.564952] device-mapper: multipath: blk_get_request() > > returned > > > > -11 - requeuing > > > > [  410.644493] device-mapper: multipath: blk_get_request() > > returned > > > > -11 - requeuing > > > > [  410.698091] device-mapper: multipath: blk_get_request() > > returned > > > > -11 - requeuing > > > > [  410.755175] device-mapper: multipath: blk_get_request() > > returned > > > > -11 - requeuing > > > > [  410.796784] device-mapper: multipath: blk_get_request() > > returned > > > > -11 - requeuing > > > > [  410.837690] device-mapper: multipath: blk_get_request() > > returned > > > > -11 - requeuing > > > > [  410.878743] device-mapper: multipath: blk_get_request() > > returned > > > > -11 - requeuing > > > > [  463.476823] multipath_clone_and_map: 32 callbacks suppressed > > > > [  463.506773] device-mapper: multipath: blk_get_request() > > returned > > > > -11 - requeuing > > > > [  463.586752] device-mapper: multipath: blk_get_request() > > returned > > > > -11 - requeuing > > > > [  463.656880] device-mapper: multipath: blk_get_request() > > returned > > > > -11 - requeuing > > > > [  463.698919] device-mapper: multipath: blk_get_request() > > returned > > > > -11 - requeuing > > > > [  463.723572] device-mapper: multipath: blk_get_request() > > returned > > > > -11 - requeuing > > > > [  463.751820] device-mapper: multipath: blk_get_request() > > returned > > > > -11 - requeuing > > > > [  463.781110] device-mapper: multipath: blk_get_request() > > returned > > > > -11 - requeuing > > > > [  463.828267] device-mapper: multipath: blk_get_request() > > returned > > > > -11 - requeuing > > > > [  463.856997] device-mapper: multipath: blk_get_request() > > returned > > > > -11 - requeuing > > > > [  463.885998] device-mapper: multipath: blk_get_request() > > returned > > > > -11 - requeuing > > > > [  468.572060] multipath_clone_and_map: 5201 callbacks > > suppressed > > > > [  468.602191] device-mapper: multipath: blk_get_request() > > returned > > > > -11 - requeuing > > > > [  468.655761] device-mapper: multipath: blk_get_request() > > returned > > > > -11 - requeuing > > > > [  468.697540] device-mapper: multipath: blk_get_request() > > returned > > > > -11 - requeuing > > > > [  468.738610] device-mapper: multipath: blk_get_request() > > returned > > > > -11 - requeuing > > > > [  468.779597] device-mapper: multipath: blk_get_request() > > returned > > > > -11 - requeuing > > > > [  468.820705] device-mapper: multipath: blk_get_request() > > returned > > > > -11 - requeuing > > > > [  468.862712] device-mapper: multipath: blk_get_request() > > returned > > > > -11 - requeuing > > > > [  468.904662] device-mapper: multipath: blk_get_request() > > returned > > > > -11 - requeuing > > > > [  468.945132] device-mapper: multipath: blk_get_request() > > returned > > > > -11 - requeuing > > > > [  468.985128] device-mapper: multipath: blk_get_request() > > returned > > > > -11 - requeuing > > > > [  473.643013] multipath_clone_and_map: 6569 callbacks > > suppressed > > > > [  473.673466] device-mapper: multipath: blk_get_request() > > returned > > > > -11 - requeuing > > > > [  473.713929] device-mapper: multipath: blk_get_request() > > returned > > > > -11 - requeuing > > > > [  473.754989] device-mapper: multipath: blk_get_request() > > returned > > > > -11 - requeuing > > > > [  473.796069] device-mapper: multipath: blk_get_request() > > returned > > > > -11 - requeuing > > > > [  473.849768] device-mapper: multipath: blk_get_request() > > returned > > > > -11 - requeuing > > > > [  473.891640] device-mapper: multipath: blk_get_request() > > returned > > > > -11 - requeuing > > > > [  473.933321] device-mapper: multipath: blk_get_request() > > returned > > > > -11 - requeuing > > > > [  473.973791] device-mapper: multipath: blk_get_request() > > returned > > > > -11 - requeuing > > > > [  474.016739] device-mapper: multipath: blk_get_request() > > returned > > > > -11 - requeuing > > > > [  474.059858] device-mapper: multipath: blk_get_request() > > returned > > > > -11 - requeuing > > > > [  478.732265] multipath_clone_and_map: 6310 callbacks > > suppressed > > > > [  478.762164] device-mapper: multipath: blk_get_request() > > returned > > > > -11 - requeuing > > > > [  478.802327] device-mapper: multipath: blk_get_request() > > returned > > > > -11 - requeuing > > > > [  478.844235] device-mapper: multipath: blk_get_request() > > returned > > > > -11 - requeuing > > > > [  478.886113] device-mapper: multipath: blk_get_request() > > returned > > > > -11 - requeuing > > > > [  478.927164] device-mapper: multipath: blk_get_request() > > returned > > > > -11 - requeuing > > > > [  478.968141] device-mapper: multipath: blk_get_request() > > returned > > > > -11 - requeuing > > > > [  479.008772] device-mapper: multipath: blk_get_request() > > returned > > > > -11 - requeuing > > > > [  479.060225] device-mapper: multipath: blk_get_request() > > returned > > > > -11 - requeuing > > > > [  479.102873] device-mapper: multipath: blk_get_request() > > returned > > > > -11 - requeuing > > > > [  479.145341] device-mapper: multipath: blk_get_request() > > returned > > > > -11 - requeuing > > > > [  483.834884] multipath_clone_and_map: 5703 callbacks > > suppressed > > > > [  483.865056] device-mapper: multipath: blk_get_request() > > returned > > > > -11 - requeuing > > > > [  483.906792] device-mapper: multipath: blk_get_request() > > returned > > > > -11 - requeuing > > > > [  483.959492] device-mapper: multipath: blk_get_request() > > returned > > > > -11 - requeuing > > > > [  484.001768] device-mapper: multipath: blk_get_request() > > returned > > > > -11 - requeuing > > > > [  484.044785] device-mapper: multipath: blk_get_request() > > returned > > > > -11 - requeuing > > > > [  484.087289] device-mapper: multipath: blk_get_request() > > returned > > > > -11 - requeuing > > > > [  484.129854] device-mapper: multipath: blk_get_request() > > returned > > > > -11 - requeuing > > > > [  484.171317] device-mapper: multipath: blk_get_request() > > returned > > > > -11 - requeuing > > > > [  484.212314] device-mapper: multipath: blk_get_request() > > returned > > > > -11 - requeuing > > > > [  484.263931] device-mapper: multipath: blk_get_request() > > returned > > > > -11 - requeuing > > > > [  484.982608] perf: interrupt took too long (10021 > 10007), > > > > lowering kernel.perf_event_max_sample_rate to 19000 > > > > [  485.362787] watchdog: BUG: soft lockup - CPU#11 stuck for > > 21s! > > > > [ksoftirqd/11:78] > > > > [  485.400762] Modules linked in: dm_round_robin xt_CHECKSUM > > > > ipt_MASQUERADE nf_nat_masquerade_ipv4 tun ip6t_rpfilter > > ipt_REJECT > > > > nf_reject_ipv4 ip6t_REJECT nf_reject_ipv6 xt_conntrack ip_set > > > > nfnetlink ebtable_nat ebtable_broute bridge stp llc > > ip6table_nat > > > > nf_conntrack_ipv6 nf_defrag_ipv6 nf_nat_ipv6 ip6table_mangle > > > > ip6table_security ip6table_raw iptable_nat nf_conntrack_ipv4 > > > > nf_defrag_ipv4 nf_nat_ipv4 nf_nat rpcrdma nf_conntrack ib_isert > > > > iscsi_target_mod iptable_mangle iptable_security iptable_raw > > > > ebtable_filter ebtables ib_iser ip6table_filter ip6_tables > > libiscsi > > > > iptable_filter scsi_transport_iscsi target_core_mod ib_srp > > > > scsi_transport_srp ib_ipoib rdma_ucm ib_ucm ib_uverbs ib_umad > > > > rdma_cm > > > > ib_cm iw_cm mlx5_ib ib_core intel_powerclamp coretemp kvm_intel > > kvm > > > > irqbypass crct10dif_pclmul crc32_pclmul ghash_clmulni_intel > > > > [  485.809222]  pcbc joydev ipmi_si aesni_intel sg hpwdt hpilo > > > > crypto_simd iTCO_wdt cryptd iTCO_vendor_support ipmi_devintf > > > > gpio_ich > > > > glue_helper shpchp lpc_ich ipmi_msghandler acpi_power_meter > > pcspkr > > > > i7core_edac pcc_cpufreq nfsd auth_rpcgss nfs_acl lockd grace > > sunrpc > > > > dm_multipath ip_tables xfs libcrc32c sd_mod amdkfd amd_iommu_v2 > > > > radeon mlx5_core i2c_algo_bit drm_kms_helper syscopyarea > > > > sysfillrect > > > > sysimgblt fb_sys_fops ttm mlxfw drm ptp hpsa pps_core > > > > scsi_transport_sas crc32c_intel bnx2 i2c_core serio_raw devlink > > > > dm_mirror dm_region_hash dm_log dm_mod [last unloaded: ib_srpt] > > > > [  486.096352] CPU: 11 PID: 78 Comm: ksoftirqd/11 Tainted: > > > > G          I     4.13.0-rc3+ #23 > > > > [  486.142775] Hardware name: HP ProLiant DL380 G7, BIOS P67 > > > > 08/16/2015 > > > > [  486.178816] task: ffff8a3fe453df40 task.stack: > > ffff9a6cc65a8000 > > > > [  486.212674] RIP: 0010:__blk_recalc_rq_segments+0xb8/0x3d0 > > > > [  486.242444] RSP: 0018:ffff9a6cc65aba60 EFLAGS: 00000282 > > > > ORIG_RAX: > > > > ffffffffffffff10 > > > > [  486.284086] RAX: ffff8a4a8e26e440 RBX: 0000000000001000 RCX: > > > > ffff8a4a8e26e440 > > > > [  486.323445] RDX: 0000000000000000 RSI: 0000000000001000 RDI: > > > > ffff8a4a8e2699c8 > > > > [  486.363614] RBP: ffff9a6cc65abae0 R08: 0000000000007000 R09: > > > > 0000000000000001 > > > > [  486.404621] R10: 0000000000001000 R11: 0000000000000000 R12: > > > > 0000000000000000 > > > > [  486.445127] R13: 0000000000000000 R14: 0000000000000001 R15: > > > > 0000000000000007 > > > > [  486.486120] FS:  0000000000000000(0000) > > > > GS:ffff8a4b66940000(0000) > > > > knlGS:0000000000000000 > > > > [  486.532771] CS:  0010 DS: 0000 ES: 0000 CR0: > > 0000000080050033 > > > > [  486.565772] CR2: 00007f32bfcee000 CR3: 0000000d67609000 CR4: > > > > 00000000000006e0 > > > > [  486.606325] Call Trace: > > > > [  486.620269]  ? mempool_free+0x2b/0x80 > > > > [  486.641248]  blk_recalc_rq_segments+0x28/0x40 > > > > [  486.666754]  blk_update_request+0x249/0x310 > > > > [  486.690838]  end_clone_bio+0x46/0x70 [dm_mod] > > > > [  486.715949]  bio_endio+0xa1/0x120 > > > > [  486.734408]  blk_update_request+0xb7/0x310 > > > > [  486.757313]  scsi_end_request+0x38/0x1d0 > > > > [  486.779375]  scsi_io_completion+0x13c/0x630 > > > > [  486.802928]  scsi_finish_command+0xd9/0x120 > > > > [  486.825875]  scsi_softirq_done+0x12a/0x150 > > > > [  486.849029]  __blk_mq_complete_request+0x90/0x140 > > > > [  486.875484]  blk_mq_complete_request+0x16/0x20 > > > > [  486.900631]  scsi_mq_done+0x21/0x70 > > > > [  486.920462]  srp_recv_done+0x48f/0x610 [ib_srp] > > > > [  486.946212]  __ib_process_cq+0x5c/0xb0 [ib_core] > > > > [  486.972576]  ib_poll_handler+0x22/0x70 [ib_core] > > > > [  486.998638]  irq_poll_softirq+0xaf/0x110 > > > > [  487.021727]  __do_softirq+0xc9/0x269 > > > > [  487.042027]  run_ksoftirqd+0x29/0x50 > > > > [  487.062675]  smpboot_thread_fn+0x110/0x160 > > > > [  487.085597]  kthread+0x109/0x140 > > > > [  487.104113]  ? sort_range+0x30/0x30 > > > > [  487.124120]  ? kthread_park+0x60/0x60 > > > > [  487.144624]  ret_from_fork+0x25/0x30 > > > > [  487.164640] Code: c3 83 fa 09 0f 84 8e 01 00 00 48 8b 44 24 > > 20 > > > > 48 > > > > 8b 4c 24 28 45 31 ff 45 31 c0 45 31 c9 0f b6 80 36 06 00 00 88 > > 44 > > > > 24 > > > > 17 8b 59 28 <44> 8b 71 2c 44 8b 61 34 85 db 0f 84 92 01 00 00 > > 45 89 > > > > f5 45 89  > > > >  > > > > Message from syslogd@ibclient at Aug  8 04:12:23 ... > > > >  kernel:watchdog: BUG: soft lockup - CPU#11 stuck for 21s! > > > > [ksoftirqd/11:78] > > > >  > > > >  > > > >  > > > > Thanks, > > > > Ming > > >  > > Hello Bart > >  > > I received your message but my work email is not seeing it. > > So I am replying to the original email by Ming so I can properly > > respond to your most recent message pasted below and keep the > thread > > in > > the right flow. > >  > > I am purposefully testing buffered I/O because as you know that was > a > > source of pain for us last year. > > So yes my intention always is to run large buffered and un-buffered > > (direct) sequential I/O as its part of my regular tests that have > > been > > very useful in discovering many issues. > > I also have smaller random and sequential I/O tests driven by fio > > that > > were not seeing the issue. > >  > > I will go ahead and test your patch below. I am not surprised Ming > > was > > able to make this happen on the stock 4.13-RC3 but he had to run 16 > > parallel jobs. > >  > > It was happening on his kernel with only 3 parallel jobs and had > not > > been happening for me with 3 parallel runs on stock upstream but > > perhaps just takes longer on 4.13-RC3 so 16 parallel runs brings it > > out. > >  > > Just one other small point, this is a "hard", not soft lockup.  > >  > > Unfortunately on the 7.3 base I am unable to capture a full vmcore > > when > > running the latest upstream kernel so if I need to get a vmcore I > > will > > have to use Fedora and the latest upstream. > >  > > I will do that if your patch is not successful but reading it and > > looking at the stack dumps I have, it makes sense. > >  > > back in a bit > >  > > Thanks > > Laurence > >  > > ---- > > Hello Laurence, > >  > > Is your goal perhaps to simulate a DDN workload? In that case I > think > > you > > need oflag=direct to the dd argument list such that the page cache > > writeback > > code does not alter the size of the write requests. Anyway, this > test > > should > > not trigger a lockup. Can you check whether the patch below makes > the > > soft > > lockup complaints disappear (without changing the hammer_write.sh > > test > > script)? > >  > > Thanks, > >  > > Bart. > > ----------------------------------------------------------------- > ---- > > ------- > > [PATCH] block: Make blk_mq_delay_kick_requeue_list() rerun the > queue > > at > > a > > quiet time > >  > > Drivers like dm-mpath requeue requests if no paths are available > and > > if configured to do so. If the queue depth is sufficiently high and > > the queue rerunning delay sufficiently short then .requeue_work can > > be queued so often that other work items queued on the same work > > queue > > do not get executed. Avoid that this happens by only rerunning the > > queue after no blk_mq_delay_kick_requeue_list() calls have occurred > > during @msecs milliseconds. Since the device mapper core is the > only > > user of blk_mq_delay_kick_requeue_list(), modify the implementation > > of this function instead of creating a new function. > >  > > Signed-off-by: Bart Van Assche > > --- > >  block/blk-mq.c | 4 ++-- > >  1 file changed, 2 insertions(+), 2 deletions(-) > >  > > diff --git a/block/blk-mq.c b/block/blk-mq.c > > index 041f7b7fa0d6..8bfea36e92f9 100644 > > --- a/block/blk-mq.c > > +++ b/block/blk-mq.c > > @@ -679,8 +679,8 @@ EXPORT_SYMBOL(blk_mq_kick_requeue_list); > >  void blk_mq_delay_kick_requeue_list(struct request_queue *q, > >                                     unsigned long msecs) > >  { > > -       kblockd_schedule_delayed_work(&q->requeue_work, > > -                                     msecs_to_jiffies(msecs)); > > +       kblockd_mod_delayed_work_on(WORK_CPU_UNBOUND, &q- > > >requeue_work, > > +                                   msecs_to_jiffies(msecs)); > >  } > >  EXPORT_SYMBOL(blk_mq_delay_kick_requeue_list); > > ----- Hello Bart So the patch is working to avoid the clone failures messages and requeue -11 messages of my original issue however both the hard lockup and soft lockup persists. It's is a lot harder to get the hard lockup now though with the patch. The soft LOCKUPS due to the spins on the ksoftirqd are almost expected because of how hard we are driving this and are easy to recreate. I did boot the original Ming kernel and reproduced first for baseline.  I then patched it with your simple patch. I was not paying enough attention to Ming's message but he was seeing a ksoftirq soft LOCKUP on the stock upstream kernel NOT the hard LOCKUP. I did not check his log message carefully so assumed he meant hard LOCKUP. I guess that's why you said "soft LOCKUP" I did get into a few soft lockups before I hit another hard LOCKUP. So I am now again not sure about the hard LOCKUP on the stock and 7.4 kernel. I will have to retest and baseline myself as Ming is away now on vacation. The soft lockups still happen but they recover unless panic_on_ soft_lockup is set and I almost expect them with how the softirqd is spinning here. We see high spin rates here and I am only running 7 parallel writes.  PID USER      PR  NI    VIRT    RES    SHR S  %CPU %MEM     TIME+ COMMAND         20 root      20   0       0      0      0 R 100.0  0.0   0:27.11 kworker/u6+     24 root      20   0       0      0      0 R 100.0  0.0   0:21.56 ksoftirqd/2     60 root      20   0       0      0      0 R 100.0  0.0   0:34.61 ksoftirqd/8  We see high SYS time because of the spinning so the soft LOCKUP is not unexpected to be honest and it recovers. #         <----CPU[HYPER]-----><-----------Memory-----------><--------- -Disks-----------> #Time     cpu sys inter  ctxsw Free Buff Cach Inac Slab  Map KBRead  Reads KBWrit Writes  21:32:11   52  52 11526  45981  65G  21G 541M  22G   7G 209M     45     11 709791    211  21:32:12   49  49 13315  26037  65G  21G 541M  22G   6G 209M      0      0 606356    195  21:32:13   47  47 13375  21456  65G  21G 541M  22G   6G 209M      0      0 591468    250  21:32:14   33  33 12635    978  65G  21G 541M  22G   5G 209M      0      0 560860    365  21:32:15   40  40 14304    734  67G  19G 541M  20G   5G 209M      0      0 429472     97  21:32:16   36  36 16060   6220  70G  17G 541M  17G   4G 209M      0      0 312852     54  21:32:17   31  31 16071   4962  71G  16G 540M  16G   4G 209M     24      6 253228     44  21:32:18   31  31 15855    868  70G  17G 540M  18G   6G 209M    104     26 237696     62  21:32:19   31  31 15983    661  70G  17G 541M  17G   7G 209M      0      0 162340     37  21:32:20   32  32 16245   1413  70G  17G 541M  18G   9G 209M     68     17 155648     19  21:32:21   44  44 14919  21711  68G  19G 540M  19G  10G 209M      0      0 303104     32  21:32:22   59  59 11661  69544  68G  19G 541M  20G  10G 209M      0      0 620919     84  21:32:23   59  59 12951   1058  67G  20G 540M  20G  10G 209M      0      0 596582    126  21:32:24   68  67 12991   2077  66G  21G 540M  21G  10G 209M      0      0 689504    168  21:32:25   78  78 13295   2927  66G  21G 541M  21G  10G 209M      0      0 667673    144  21:32:26   66  66 13498   7670  65G  21G 541M  22G  10G 209M      0      0 626874     98  21:32:27   55  55 12203   2663  65G  21G 541M  22G   9G 209M      0      0 652096    112  21:32:28   47  47 12567  27804  65G  21G 541M  22G   8G 209M      0      0 534789    137 We are driving this system pretty hard here and the target server is seeing queue fulls and I am used to these if I drive it too hard. [  568.707572] ib_srpt srpt_write_pending: IB send queue full (needed 97) [  568.745714] ib_srpt srpt_write_pending: IB send queue full (needed 97) [  568.783735] ib_srpt srpt_write_pending: IB send queue full (needed 97) [  568.821583] ib_srpt srpt_write_pending: IB send queue full (needed 97) [  568.858238] ib_srpt srpt_write_pending: IB send queue full (needed 97) [  568.895975] ib_srpt srpt_queue_response: IB send queue full (needed 0) [  568.934253] ib_srpt srpt_write_pending: IB send queue full (needed 97) [  568.971040] ib_srpt srpt_write_pending: IB send queue full (needed 49) So your patch helps to avoid easily getting the hard LOCKUP, does not help the Soft lockup (as expected). [  329.305507] watchdog: BUG: soft lockup - CPU#12 stuck for 21s! [ksoftirqd/12:84] [  329.305508] Modules linked in: dm_round_robin mq_deadline xt_CHECKSUM ipt_MASQUERADE nf_nat_masquerade_ipv4 tun ip6t_rpfilter ipt_REJECT nf_reject_ipv4 ip6t_REJECT nf_reject_ipv6 xt_conntrack ip_set nfnetlink ebtable_nat ebtable_broute bridge stp llc ip6table_nat nf_conntrack_ipv6 nf_defrag_ipv6 nf_nat_ipv6 ip6table_mangle ip6table_security ip6table_raw iptable_nat nf_conntrack_ipv4 nf_defrag_ipv4 nf_nat_ipv4 nf_nat rpcrdma nf_conntrack ib_isert iptable_mangle iptable_security iscsi_target_mod iptable_raw ebtable_filter ebtables ip6table_filter ib_iser ip6_tables libiscsi iptable_filter scsi_transport_iscsi target_core_mod ib_srp scsi_transport_srp ib_ipoib rdma_ucm ib_ucm ib_uverbs ib_umad rdma_cm ib_cm iw_cm mlx5_ib ib_core intel_powerclamp coretemp kvm_intel kvm irqbypass crct10dif_pclmul crc32_pclmul [  329.305543]  ghash_clmulni_intel pcbc joydev aesni_intel ipmi_si sg hpilo ipmi_devintf hpwdt crypto_simd iTCO_wdt gpio_ich iTCO_vendor_support cryptd shpchp acpi_power_meter ipmi_msghandler i7core_edac glue_helper pcspkr lpc_ich pcc_cpufreq nfsd auth_rpcgss nfs_acl lockd grace sunrpc dm_multipath ip_tables xfs libcrc32c sd_mod amdkfd amd_iommu_v2 radeon mlx5_core i2c_algo_bit drm_kms_helper syscopyarea sysfillrect sysimgblt fb_sys_fops ttm mlxfw ptp drm pps_core hpsa i2c_core devlink crc32c_intel serio_raw bnx2 scsi_transport_sas dm_mirror dm_region_hash dm_log dm_mod [last unloaded: ib_srpt] [  329.305564] CPU: 12 PID: 84 Comm: ksoftirqd/12 Tainted: G          I     4.13.0-rc3.ming.bart+ #1 [  329.305566] Hardware name: HP ProLiant DL380 G7, BIOS P67 08/16/2015 [  329.305567] task: ffff91a94c070040 task.stack: ffffaa8ec65d8000 [  329.305573] RIP: 0010:__blk_recalc_rq_segments+0x1a7/0x3d0 [  329.305574] RSP: 0018:ffffaa8ec65dba60 EFLAGS: 00000202 ORIG_RAX: ffffffffffffff10 [  329.305575] RAX: 0000000000000001 RBX: 0000000000001000 RCX: ffff91b1149239c0 [  329.305576] RDX: 0000000000001000 RSI: 0000000000000001 RDI: 0000000000001000 [  329.305577] RBP: ffffaa8ec65dbae0 R08: 0000000000001000 R09: 0000000000000001 [  329.305578] R10: 0000000b2a506000 R11: 0000000000000000 R12: 0000000000000000 [  329.305579] R13: 0000000000000000 R14: 0000000000000000 R15: 000000000000002e [  329.305580] FS:  0000000000000000(0000) GS:ffff91b3b7b80000(0000) knlGS:0000000000000000 [  329.305581] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [  329.305582] CR2: 00007ff4591f1860 CR3: 0000000985e09000 CR4: 00000000000006e0 [  329.305583] Call Trace: [  329.305588]  ? mempool_free+0x2b/0x80 [  329.305590]  blk_recalc_rq_segments+0x28/0x40 [  329.305592]  blk_update_request+0x249/0x310 [  329.305603]  end_clone_bio+0x46/0x70 [dm_mod] [  329.305607]  bio_endio+0xa1/0x120 [  329.305608]  blk_update_request+0xb7/0x310 [  329.305611]  scsi_end_request+0x38/0x1d0 [  329.305613]  scsi_io_completion+0x13c/0x630 [  329.305615]  scsi_finish_command+0xd9/0x120 [  329.305616]  scsi_softirq_done+0x12a/0x150 [  329.305618]  __blk_mq_complete_request+0x90/0x140 [  329.305624]  blk_mq_complete_request+0x16/0x20 [  329.305625]  scsi_mq_done+0x21/0x70 [  329.305628]  srp_recv_done+0x48f/0x610 [ib_srp] [  329.305639]  __ib_process_cq+0x5c/0xb0 [ib_core] [  329.305646]  ib_poll_handler+0x22/0x70 [ib_core] [  329.305649]  irq_poll_softirq+0xaf/0x110 [  329.305652]  __do_softirq+0xc9/0x269 [  329.305655]  run_ksoftirqd+0x29/0x50 [  329.305657]  smpboot_thread_fn+0x110/0x160 [  329.305659]  kthread+0x109/0x140 [  329.305660]  ? sort_range+0x30/0x30 [  329.305661]  ? kthread_park+0x60/0x60 [  329.305663]  ret_from_fork+0x25/0x30 [  329.305664] Code: 8b 74 24 30 48 8b 7c 24 38 41 83 c7 01 41 89 d0 41 b9 01 00 00 00 48 89 74 24 40 48 89 7c 24 48 8b 41 14 0f b6 f0 25 fb 00 00 00 <83> f8 03 0f 84 a0 00 00 00 83 fe 05 0f 84 97 00 00 00 83 fe 09  [  331.465885] CPU: 4 PID: 36 Comm: ksoftirqd/4 Tainted: G          I  L  4.13.0-rc3.ming.bart+ #1 [  331.516413] Hardware name: HP ProLiant DL380 G7, BIOS P67 08/16/2015 [  331.551403] task: ffff91a94c76df40 task.stack: ffffaa8ec6458000 [  331.584080] RIP: 0010:__blk_recalc_rq_segments+0xdf/0x3d0 [  331.614515] RSP: 0018:ffffaa8ec645ba60 EFLAGS: 00000286 ORIG_RAX: ffffffffffffff10 [  331.656098] RAX: 0000000000001000 RBX: 0000000000001000 RCX: ffff91b29faecdc0 [  331.696577] RDX: ffffe839e5d75300 RSI: ffff91b29faece48 RDI: ffff91b2831f8348 [  331.736607] RBP: ffffaa8ec645bae0 R08: 0000000000004000 R09: 0000000000000001 [  331.776129] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 [  331.817085] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000021 [  331.857671] FS:  0000000000000000(0000) GS:ffff91b3b7a80000(0000) knlGS:0000000000000000 [  331.904232] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [  331.935249] CR2: 00007f404526e000 CR3: 0000000985e09000 CR4: 00000000000006e0 [  331.976273] Call Trace: [  331.990216]  ? mempool_free+0x2b/0x80 [  332.010310]  blk_recalc_rq_segments+0x28/0x40 [  332.034810]  blk_update_request+0x249/0x310 [  332.058259]  end_clone_bio+0x46/0x70 [dm_mod] [  332.082851]  bio_endio+0xa1/0x120 [  332.101145]  blk_update_request+0xb7/0x310 [  332.123965]  scsi_end_request+0x38/0x1d0 [  332.145943]  scsi_io_completion+0x13c/0x630 [  332.169357]  scsi_finish_command+0xd9/0x120 [  332.193505]  scsi_softirq_done+0x12a/0x150 [  332.217044]  __blk_mq_complete_request+0x90/0x140 [  332.244498]  blk_mq_complete_request+0x16/0x20 [  332.269971]  scsi_mq_done+0x21/0x70 [  332.289591]  srp_recv_done+0x48f/0x610 [ib_srp] [  332.315609]  __ib_process_cq+0x5c/0xb0 [ib_core] [  332.342144]  ib_poll_handler+0x22/0x70 [ib_core] [  332.368724]  irq_poll_softirq+0xaf/0x110 [  332.392595]  __do_softirq+0xc9/0x269 [  332.413220]  run_ksoftirqd+0x29/0x50 [  332.433214]  smpboot_thread_fn+0x110/0x160 [  332.456254]  kthread+0x109/0x140 [  332.475263]  ? sort_range+0x30/0x30 [  332.494624]  ? kthread_park+0x60/0x60 [  332.515413]  ret_from_fork+0x25/0x30 [  332.535180] Code: 17 8b 59 28 44 8b 71 2c 44 8b 61 34 85 db 0f 84 92 01 00 00 45 89 f5 45 89 e2 4c 89 ee 48 c1 e6 04 48 03 71 78 8b 46 08 48 8b 16 <44> 29 e0 48 89 54 24 30 39 d8 0f 47 c3 44 03 56 0c 45 84 db 89  Message from syslogd@ibclient at Aug  8 22:06:38 ...  kernel:watchdog: BUG: soft lockup - CPU#4 stuck for 23s! [ksoftirqd/4:36] Message from syslogd@ibclient at Aug  8 22:06:38 ...  kernel:watchdog: BUG: soft lockup - CPU#12 stuck for 21s! [ksoftirqd/12:84] I am going to leave this running overnight and see if I wake up to another hard lockup. Thanks as always, again the patch has helped in two ways. 1. It avoids the clone failure and requeue -11 failure messages 2. It seems to take a lot longe rnow to get into a hard lockup. Regards Laurence