On 2/2/25 8:06 PM, Dai Ngo wrote: > > On 2/2/25 8:18 AM, Chuck Lever wrote: >> On 2/2/25 8:35 AM, Salvatore Bonaccorso wrote: >>> Hi Chuck, >>> >>> On Fri, Jan 31, 2025 at 05:17:08PM +0100, Salvatore Bonaccorso wrote: >>>> Hi Chuck, >>>> >>>> On Sat, Aug 17, 2024 at 02:52:38PM +0000, Chuck Lever III wrote: >>>>> >>>>>> On Aug 17, 2024, at 4:39 AM, Salvatore Bonaccorso >>>>>> <carnil@xxxxxxxxxx> wrote: >>>>>> >>>>>> Hi, >>>>>> >>>>>> On Tue, Jul 30, 2024 at 02:52:47PM +0200, Paul Menzel wrote: >>>>>>> Dear Salvatore, dear Chuck, >>>>>>> >>>>>>> >>>>>>> Thank you for your messages. >>>>>>> >>>>>>> >>>>>>> Am 30.07.24 um 14:19 schrieb Salvatore Bonaccorso: >>>>>>> >>>>>>>> On Sat, Jul 27, 2024 at 09:19:24PM +0000, Chuck Lever III wrote: >>>>>>>>>> On Jul 27, 2024, at 5:15 PM, Salvatore Bonaccorso >>>>>>>>>> <carnil@xxxxxxxxxx> wrote: >>>>>>>>>> On Wed, Jul 17, 2024 at 07:33:24AM +0200, Paul Menzel wrote: >>>>>>>>>>> Using Linux 5.15.160 on a Dell PowerEdge T440/021KCD, BIOS >>>>>>>>>>> 2.11.2 >>>>>>>>>>> 04/22/2021, a mount from another server hung. Linux logs: >>>>>>>>>>> >>>>>>>>>>> ``` >>>>>>>>>>> $ dmesg -T >>>>>>>>>>> [Wed Jul 3 16:39:34 2024] Linux version >>>>>>>>>>> 5.15.160.mx64.476(root@xxxxxxxxxxxxxxxxxxxxxxxxx) (gcc (GCC) >>>>>>>>>>> 12.3.0, GNU ld (GNU Binutils) 2.41) #1 SMP Wed Jun 5 12:24:15 >>>>>>>>>>> CEST 2024 >>>>>>>>>>> [Wed Jul 3 16:39:34 2024] Command line: root=LABEL=root ro >>>>>>>>>>> crashkernel=64G-:256M console=ttyS0,115200n8 console=tty0 >>>>>>>>>>> init=/bin/systemd audit=0 random.trust_cpu=on >>>>>>>>>>> systemd.unified_cgroup_hierarchy >>>>>>>>>>> […] >>>>>>>>>>> [Wed Jul 3 16:39:34 2024] DMI: Dell Inc. PowerEdge >>>>>>>>>>> T440/021KCD, BIOS 2.11.2 04/22/2021 >>>>>>>>>>> […] >>>>>>>>>>> [Tue Jul 16 06:00:10 2024] md: md3: data-check interrupted. >>>>>>>>>>> [Tue Jul 16 11:06:01 2024] receive_cb_reply: Got unrecognized >>>>>>>>>>> reply: calldir 0x1 xpt_bc_xprt 00000000ee580afa xid 6890a3d2 >>>>>>>>>>> [Tue Jul 16 11:06:01 2024] receive_cb_reply: Got unrecognized >>>>>>>>>>> reply: calldir 0x1 xpt_bc_xprt 00000000d4d84570 xid 3ca4017a >>>>>>> […] >>>>>>> >>>>>>>>>>> [Tue Jul 16 11:35:59 2024] receive_cb_reply: Got unrecognized >>>>>>>>>>> reply: calldir 0x1 xpt_bc_xprt 0000000028481e8f xid b682b676 >>>>>>>>>>> [Tue Jul 16 11:35:59 2024] receive_cb_reply: Got unrecognized >>>>>>>>>>> reply: calldir 0x1 xpt_bc_xprt 00000000c384ff38 xid b5d5dbf5 >>>>>>>>>>> [Tue Jul 16 11:36:40 2024] rcu: INFO: rcu_sched self-detected >>>>>>>>>>> stall on CPU >>>>>>>>>>> [Tue Jul 16 11:36:40 2024] rcu: 13-....: (20997 ticks this >>>>>>>>>>> GP) idle=54f/1/0x4000000000000000 softirq=31904928/31904928 >>>>>>>>>>> fqs=4433 >>>>>>>>>>> [Tue Jul 16 11:36:40 2024] (t=21017 jiffies g=194958993 q=5715) >>>>>>>>>>> [Tue Jul 16 11:36:40 2024] Task dump for CPU 13: >>>>>>>>>>> [Tue Jul 16 11:36:40 2024] task:kworker/u34:2 state:R >>>>>>>>>>> running task stack: 0 pid:30413 ppid: 2 flags:0x00004008 >>>>>>>>>>> [Tue Jul 16 11:36:40 2024] Workqueue: rpciod >>>>>>>>>>> rpc_async_schedule [sunrpc] >>>>>>>>>>> [Tue Jul 16 11:36:40 2024] Call Trace: >>>>>>>>>>> [Tue Jul 16 11:36:40 2024] <IRQ> >>>>>>>>>>> [Tue Jul 16 11:36:40 2024] sched_show_task.cold+0xc2/0xda >>>>>>>>>>> [Tue Jul 16 11:36:40 2024] rcu_dump_cpu_stacks+0xa1/0xd3 >>>>>>>>>>> [Tue Jul 16 11:36:40 2024] rcu_sched_clock_irq.cold+0xc7/0x1e7 >>>>>>>>>>> [Tue Jul 16 11:36:40 2024] ? trigger_load_balance+0x6d/0x300 >>>>>>>>>>> [Tue Jul 16 11:36:40 2024] ? scheduler_tick+0xda/0x260 >>>>>>>>>>> [Tue Jul 16 11:36:40 2024] update_process_times+0xa1/0xe0 >>>>>>>>>>> [Tue Jul 16 11:36:40 2024] tick_sched_timer+0x8e/0xa0 >>>>>>>>>>> [Tue Jul 16 11:36:40 2024] ? tick_sched_do_timer+0x90/0x90 >>>>>>>>>>> [Tue Jul 16 11:36:40 2024] __hrtimer_run_queues+0x139/0x2a0 >>>>>>>>>>> [Tue Jul 16 11:36:40 2024] hrtimer_interrupt+0xf4/0x210 >>>>>>>>>>> [Tue Jul 16 11:36:40 2024] >>>>>>>>>>> __sysvec_apic_timer_interrupt+0x5f/0xe0 >>>>>>>>>>> [Tue Jul 16 11:36:40 2024] >>>>>>>>>>> sysvec_apic_timer_interrupt+0x69/0x90 >>>>>>>>>>> [Tue Jul 16 11:36:40 2024] </IRQ> >>>>>>>>>>> [Tue Jul 16 11:36:40 2024] <TASK> >>>>>>>>>>> [Tue Jul 16 11:36:40 2024] >>>>>>>>>>> asm_sysvec_apic_timer_interrupt+0x16/0x20 >>>>>>>>>>> [Tue Jul 16 11:36:40 2024] RIP: 0010:read_tsc+0x3/0x20 >>>>>>>>>>> [Tue Jul 16 11:36:40 2024] Code: cc cc cc cc cc cc cc 8b 05 >>>>>>>>>>> 56 ab 72 01 c3 cc cc cc cc 0f 1f 44 00 00 c3 cc cc cc cc 66 >>>>>>>>>>> 66 2e 0f 1f 84 00 00 00 00 00 0f 01 f9 <66> 90 48 c1 e2 20 48 >>>>>>>>>>> 09 d0 c3 cc cc cc cc 66 66 2e 0f 1f 84 00 00 >>>>>>>>>>> [Tue Jul 16 11:36:40 2024] RSP: 0018:ffffc900087cfe00 EFLAGS: >>>>>>>>>>> 00000246 >>>>>>>>>>> [Tue Jul 16 11:36:40 2024] RAX: 00000000226dc8b8 RBX: >>>>>>>>>>> 000000003f3c079e RCX: 000000000000100d >>>>>>>>>>> [Tue Jul 16 11:36:40 2024] RDX: 00000000004535c4 RSI: >>>>>>>>>>> 0000000000000046 RDI: ffffffff82435600 >>>>>>>>>>> [Tue Jul 16 11:36:40 2024] RBP: 0003ed08d3641da3 R08: >>>>>>>>>>> ffffffffa012c770 R09: ffffffffa012c788 >>>>>>>>>>> [Tue Jul 16 11:36:40 2024] R10: 0000000000000003 R11: >>>>>>>>>>> 0000000000000283 R12: 0000000000000000 >>>>>>>>>>> [Tue Jul 16 11:36:40 2024] R13: 0000000000000001 R14: >>>>>>>>>>> ffff88909311c000 R15: ffff88909311c005 >>>>>>>>>>> [Tue Jul 16 11:36:40 2024] ktime_get+0x38/0xa0 >>>>>>>>>>> [Tue Jul 16 11:36:40 2024] ? rpc_sleep_on_priority+0x70/0x70 >>>>>>>>>>> [sunrpc] >>>>>>>>>>> [Tue Jul 16 11:36:40 2024] rpc_exit_task+0x9a/0x100 [sunrpc] >>>>>>>>>>> [Tue Jul 16 11:36:40 2024] __rpc_execute+0x6e/0x410 [sunrpc] >>>>>>>>>>> [Tue Jul 16 11:36:40 2024] rpc_async_schedule+0x29/0x40 >>>>>>>>>>> [sunrpc] >>>>>>>>>>> [Tue Jul 16 11:36:40 2024] process_one_work+0x1d7/0x3a0 >>>>>>>>>>> [Tue Jul 16 11:36:40 2024] worker_thread+0x4a/0x3c0 >>>>>>>>>>> [Tue Jul 16 11:36:40 2024] ? process_one_work+0x3a0/0x3a0 >>>>>>>>>>> [Tue Jul 16 11:36:40 2024] kthread+0x115/0x140 >>>>>>>>>>> [Tue Jul 16 11:36:40 2024] ? set_kthread_struct+0x50/0x50 >>>>>>>>>>> [Tue Jul 16 11:36:40 2024] ret_from_fork+0x1f/0x30 >>>>>>>>>>> [Tue Jul 16 11:36:40 2024] </TASK> >>>>>>>>>>> [Tue Jul 16 11:37:19 2024] rcu: INFO: rcu_sched self-detected >>>>>>>>>>> stall on CPU >>>>>>>>>>> [Tue Jul 16 11:37:19 2024] rcu: 7-....: (21000 ticks this >>>>>>>>>>> GP) idle=5b1/1/0x4000000000000000 softirq=29984492/29984492 >>>>>>>>>>> fqs=5159 >>>>>>>>>>> [Tue Jul 16 11:37:19 2024] (t=21017 jiffies g=194959001 q=2008) >>>>>>>>>>> [Tue Jul 16 11:37:19 2024] Task dump for CPU 7: >>>>>>>>>>> [Tue Jul 16 11:37:19 2024] task:kworker/u34:2 state:R >>>>>>>>>>> running task stack: 0 pid:30413 ppid: 2 flags:0x00004008 >>>>>>>>>>> [Tue Jul 16 11:37:19 2024] Workqueue: rpciod >>>>>>>>>>> rpc_async_schedule [sunrpc] >>>>>>>>>>> [Tue Jul 16 11:37:19 2024] Call Trace: >>>>>>>>>>> [Tue Jul 16 11:37:19 2024] <IRQ> >>>>>>>>>>> [Tue Jul 16 11:37:19 2024] sched_show_task.cold+0xc2/0xda >>>>>>>>>>> [Tue Jul 16 11:37:19 2024] rcu_dump_cpu_stacks+0xa1/0xd3 >>>>>>>>>>> [Tue Jul 16 11:37:19 2024] rcu_sched_clock_irq.cold+0xc7/0x1e7 >>>>>>>>>>> [Tue Jul 16 11:37:19 2024] ? trigger_load_balance+0x6d/0x300 >>>>>>>>>>> [Tue Jul 16 11:37:19 2024] ? scheduler_tick+0xda/0x260 >>>>>>>>>>> [Tue Jul 16 11:37:19 2024] update_process_times+0xa1/0xe0 >>>>>>>>>>> [Tue Jul 16 11:37:19 2024] tick_sched_timer+0x8e/0xa0 >>>>>>>>>>> [Tue Jul 16 11:37:19 2024] ? tick_sched_do_timer+0x90/0x90 >>>>>>>>>>> [Tue Jul 16 11:37:19 2024] __hrtimer_run_queues+0x139/0x2a0 >>>>>>>>>>> [Tue Jul 16 11:37:19 2024] hrtimer_interrupt+0xf4/0x210 >>>>>>>>>>> [Tue Jul 16 11:37:19 2024] >>>>>>>>>>> __sysvec_apic_timer_interrupt+0x5f/0xe0 >>>>>>>>>>> [Tue Jul 16 11:37:19 2024] >>>>>>>>>>> sysvec_apic_timer_interrupt+0x69/0x90 >>>>>>>>>>> [Tue Jul 16 11:37:19 2024] </IRQ> >>>>>>>>>>> [Tue Jul 16 11:37:19 2024] <TASK> >>>>>>>>>>> [Tue Jul 16 11:37:19 2024] >>>>>>>>>>> asm_sysvec_apic_timer_interrupt+0x16/0x20 >>>>>>>>>>> [Tue Jul 16 11:37:19 2024] RIP: 0010:_raw_spin_lock+0x10/0x20 >>>>>>>>>>> [Tue Jul 16 11:37:19 2024] Code: b8 00 02 00 00 f0 0f c1 07 >>>>>>>>>>> a9 ff 01 00 00 75 05 c3 cc cc cc cc e9 f0 05 59 ff 0f 1f 44 >>>>>>>>>>> 00 00 31 c0 ba 01 00 00 00 f0 0f b1 17 <75> 05 c3 cc cc cc cc >>>>>>>>>>> 89 c6 e9 62 02 59 ff 66 90 0f 1f 44 00 00 fa >>>>>>>>>>> [Tue Jul 16 11:37:19 2024] RSP: 0018:ffffc900087cfe30 EFLAGS: >>>>>>>>>>> 00000246 >>>>>>>>>>> [Tue Jul 16 11:37:19 2024] RAX: 0000000000000000 RBX: >>>>>>>>>>> ffff88997131a500 RCX: 0000000000000001 >>>>>>>>>>> [Tue Jul 16 11:37:19 2024] RDX: 0000000000000001 RSI: >>>>>>>>>>> ffff88997131a500 RDI: ffffffffa012c700 >>>>>>>>>>> [Tue Jul 16 11:37:19 2024] RBP: ffffffffa012c700 R08: >>>>>>>>>>> ffffffffa012c770 R09: ffffffffa012c788 >>>>>>>>>>> [Tue Jul 16 11:37:19 2024] R10: 0000000000000003 R11: >>>>>>>>>>> 0000000000000283 R12: ffff88997131a530 >>>>>>>>>>> [Tue Jul 16 11:37:19 2024] R13: 0000000000000001 R14: >>>>>>>>>>> ffff88909311c000 R15: ffff88909311c005 >>>>>>>>>>> [Tue Jul 16 11:37:19 2024] __rpc_execute+0x95/0x410 [sunrpc] >>>>>>>>>>> [Tue Jul 16 11:37:19 2024] rpc_async_schedule+0x29/0x40 >>>>>>>>>>> [sunrpc] >>>>>>>>>>> [Tue Jul 16 11:37:19 2024] process_one_work+0x1d7/0x3a0 >>>>>>>>>>> [Tue Jul 16 11:37:19 2024] worker_thread+0x4a/0x3c0 >>>>>>>>>>> [Tue Jul 16 11:37:19 2024] ? process_one_work+0x3a0/0x3a0 >>>>>>>>>>> [Tue Jul 16 11:37:19 2024] kthread+0x115/0x140 >>>>>>>>>>> [Tue Jul 16 11:37:19 2024] ? set_kthread_struct+0x50/0x50 >>>>>>>>>>> [Tue Jul 16 11:37:19 2024] ret_from_fork+0x1f/0x30 >>>>>>>>>>> [Tue Jul 16 11:37:19 2024] </TASK> >>>>>>>>>>> [Tue Jul 16 11:37:57 2024] rcu: INFO: rcu_sched self-detected >>>>>>>>>>> stall on CPU >>>>>>>>>>> […] >>>>>>>>>>> ``` >>>>>>>>>> FWIW, on one NFS server occurence we are seeing something very >>>>>>>>>> close >>>>>>>>>> to the above but in the 5.10.y case for the Debian kernel after >>>>>>>>>> updating to 5.10.218-1 to 5.10.221-1, so kernel after which >>>>>>>>>> had the >>>>>>>>>> big NFS related stack backported. >>>>>>>>>> >>>>>>>>>> One backtrace we were able to catch was >>>>>>>>>> >>>>>>>>>> [...] >>>>>>>>>> Jul 27 15:24:52 nfsserver kernel: receive_cb_reply: Got >>>>>>>>>> unrecognized reply: calldir 0x1 xpt_bc_xprt 000000003d26f7ec >>>>>>>>>> xid b172e1c6 >>>>>>>>>> Jul 27 15:24:52 nfsserver kernel: receive_cb_reply: Got >>>>>>>>>> unrecognized reply: calldir 0x1 xpt_bc_xprt 0000000017f1552a >>>>>>>>>> xid a90d7751 >>>>>>>>>> Jul 27 15:24:52 nfsserver kernel: receive_cb_reply: Got >>>>>>>>>> unrecognized reply: calldir 0x1 xpt_bc_xprt 000000006337c521 >>>>>>>>>> xid 8e5e58bd >>>>>>>>>> Jul 27 15:24:54 nfsserver kernel: receive_cb_reply: Got >>>>>>>>>> unrecognized reply: calldir 0x1 xpt_bc_xprt 00000000cbf89319 >>>>>>>>>> xid c2da3c73 >>>>>>>>>> Jul 27 15:24:54 nfsserver kernel: receive_cb_reply: Got >>>>>>>>>> unrecognized reply: calldir 0x1 xpt_bc_xprt 00000000e2588a21 >>>>>>>>>> xid a01bfec6 >>>>>>>>>> Jul 27 15:24:54 nfsserver kernel: receive_cb_reply: Got >>>>>>>>>> unrecognized reply: calldir 0x1 xpt_bc_xprt 000000005fda63ca >>>>>>>>>> xid c2eeeaa6 >>>>>>>>>> [...] >>>>>>>>>> Jul 27 15:25:15 nfsserver kernel: rcu: INFO: rcu_sched self- >>>>>>>>>> detected stall on CPU >>>>>>>>>> Jul 27 15:25:15 nfsserver kernel: rcu: 15-....: (5250 >>>>>>>>>> ticks this GP) idle=74e/1/0x4000000000000000 >>>>>>>>>> softirq=3160997/3161006 fqs=2233 >>>>>>>>>> Jul 27 15:25:15 nfsserver kernel: (t=5255 jiffies >>>>>>>>>> g=8381377 q=106333) >>>>>>>>>> Jul 27 15:25:15 nfsserver kernel: NMI backtrace for cpu 15 >>>>>>>>>> Jul 27 15:25:15 nfsserver kernel: CPU: 15 PID: 3725556 Comm: >>>>>>>>>> kworker/u42:4 Not tainted 5.10.0-31-amd64 #1 Debian 5.10.221-1 >>>>>>>>>> Jul 27 15:25:15 nfsserver kernel: Hardware name: DALCO AG >>>>>>>>>> S2600WFT/S2600WFT, BIOS SE5C620.86B.02.01.0008.031920191559 >>>>>>>>>> 03/19/2019 >>>>>>>>>> Jul 27 15:25:15 nfsserver kernel: Workqueue: rpciod >>>>>>>>>> rpc_async_schedule [sunrpc] >>>>>>>>>> Jul 27 15:25:15 nfsserver kernel: Call Trace: >>>>>>>>>> Jul 27 15:25:15 nfsserver kernel: <IRQ> >>>>>>>>>> Jul 27 15:25:15 nfsserver kernel: dump_stack+0x6b/0x83 >>>>>>>>>> Jul 27 15:25:15 nfsserver kernel: >>>>>>>>>> nmi_cpu_backtrace.cold+0x32/0x69 >>>>>>>>>> Jul 27 15:25:15 nfsserver kernel: ? >>>>>>>>>> lapic_can_unplug_cpu+0x80/0x80 >>>>>>>>>> Jul 27 15:25:15 nfsserver kernel: >>>>>>>>>> nmi_trigger_cpumask_backtrace+0xdf/0xf0 >>>>>>>>>> Jul 27 15:25:15 nfsserver kernel: rcu_dump_cpu_stacks+0xa5/0xd7 >>>>>>>>>> Jul 27 15:25:15 nfsserver kernel: >>>>>>>>>> rcu_sched_clock_irq.cold+0x202/0x3d9 >>>>>>>>>> Jul 27 15:25:15 nfsserver kernel: ? >>>>>>>>>> trigger_load_balance+0x5a/0x220 >>>>>>>>>> Jul 27 15:25:15 nfsserver kernel: update_process_times+0x8c/0xc0 >>>>>>>>>> Jul 27 15:25:15 nfsserver kernel: tick_sched_handle+0x22/0x60 >>>>>>>>>> Jul 27 15:25:15 nfsserver kernel: tick_sched_timer+0x65/0x80 >>>>>>>>>> Jul 27 15:25:15 nfsserver kernel: ? >>>>>>>>>> tick_sched_do_timer+0x90/0x90 >>>>>>>>>> Jul 27 15:25:15 nfsserver kernel: >>>>>>>>>> __hrtimer_run_queues+0x127/0x280 >>>>>>>>>> Jul 27 15:25:15 nfsserver kernel: hrtimer_interrupt+0x110/0x2c0 >>>>>>>>>> Jul 27 15:25:15 nfsserver kernel: >>>>>>>>>> __sysvec_apic_timer_interrupt+0x5c/0xe0 >>>>>>>>>> Jul 27 15:25:15 nfsserver kernel: asm_call_irq_on_stack+0xf/0x20 >>>>>>>>>> Jul 27 15:25:15 nfsserver kernel: </IRQ> >>>>>>>>>> Jul 27 15:25:15 nfsserver kernel: >>>>>>>>>> sysvec_apic_timer_interrupt+0x72/0x80 >>>>>>>>>> Jul 27 15:25:15 nfsserver kernel: >>>>>>>>>> asm_sysvec_apic_timer_interrupt+0x12/0x20 >>>>>>>>>> Jul 27 15:25:15 nfsserver kernel: RIP: >>>>>>>>>> 0010:mod_delayed_work_on+0x5d/0x90 >>>>>>>>>> Jul 27 15:25:15 nfsserver kernel: Code: 00 4c 89 e7 e8 34 fe >>>>>>>>>> ff ff 89 c3 83 f8 f5 74 e9 85 c0 78 1b 89 ef 4c 89 f1 4c 89 e2 >>>>>>>>>> 4c 89 ee e8 f9 fc ff ff 48 8b 3c 24 57 9d <0f> 1f 44 > >>>>>>>>>> Jul 27 15:25:15 nfsserver kernel: RSP: 0018:ffffb5efe356fd90 >>>>>>>>>> EFLAGS: 00000246 >>>>>>>>>> Jul 27 15:25:15 nfsserver kernel: RAX: 0000000000000000 RBX: >>>>>>>>>> 0000000000000000 RCX: 000000003820000f >>>>>>>>>> Jul 27 15:25:15 nfsserver kernel: RDX: 0000000038000000 RSI: >>>>>>>>>> 0000000000000046 RDI: 0000000000000246 >>>>>>>>>> Jul 27 15:25:15 nfsserver kernel: RBP: 0000000000002000 R08: >>>>>>>>>> ffffffffc0884430 R09: ffffffffc0884448 >>>>>>>>>> Jul 27 15:25:15 nfsserver kernel: R10: 0000000000000003 R11: >>>>>>>>>> 0000000000000003 R12: ffffffffc0884428 >>>>>>>>>> Jul 27 15:25:15 nfsserver kernel: R13: ffff8c89d0f6b800 R14: >>>>>>>>>> 00000000000001f4 R15: 0000000000000000 >>>>>>>>>> Jul 27 15:25:15 nfsserver kernel: >>>>>>>>>> __rpc_sleep_on_priority_timeout+0x111/0x120 [sunrpc] >>>>>>>>>> Jul 27 15:25:15 nfsserver kernel: rpc_delay+0x56/0x90 [sunrpc] >>>>>>>>>> Jul 27 15:25:15 nfsserver kernel: rpc_exit_task+0x5a/0x140 >>>>>>>>>> [sunrpc] >>>>>>>>>> Jul 27 15:25:15 nfsserver kernel: ? >>>>>>>>>> __rpc_do_wake_up_task_on_wq+0x1e0/0x1e0 [sunrpc] >>>>>>>>>> Jul 27 15:25:15 nfsserver kernel: __rpc_execute+0x6d/0x410 >>>>>>>>>> [sunrpc] >>>>>>>>>> Jul 27 15:25:15 nfsserver kernel: >>>>>>>>>> rpc_async_schedule+0x29/0x40 [sunrpc] >>>>>>>>>> Jul 27 15:25:15 nfsserver kernel: process_one_work+0x1b3/0x350 >>>>>>>>>> Jul 27 15:25:15 nfsserver kernel: worker_thread+0x53/0x3e0 >>>>>>>>>> Jul 27 15:25:15 nfsserver kernel: ? process_one_work+0x350/0x350 >>>>>>>>>> Jul 27 15:25:15 nfsserver kernel: kthread+0x118/0x140 >>>>>>>>>> Jul 27 15:25:15 nfsserver kernel: ? >>>>>>>>>> __kthread_bind_mask+0x60/0x60 >>>>>>>>>> Jul 27 15:25:15 nfsserver kernel: ret_from_fork+0x1f/0x30 >>>>>>>>>> [...] >>>>>>>>>> >>>>>>>>>> Is there anything which could help debug this issue? >>>>>>>>> The backtrace suggests an issue in the RPC client code; the >>>>>>>>> server's NFSv4.1 backchannel would use that to send callbacks. >>>>>>>>> >>>>>>>>> Since 5.10.218 and 5.10.221 are only about a thousand commits >>>>>>>>> apart, a bisect should be quick and narrow down the issue to >>>>>>>>> one or two commits. >>>>>>>> Yes indeed. Unfortunately was yet unable to reproduce the issue in >>>>>>>> more syntentic way on test environment, and the affected server in >>>>>>>> particular is a production system. >>>>>>>> >>>>>>>> Paul, is your case in some way reproducible in a testing >>>>>>>> environment >>>>>>>> so that a bisection might be give enough hints on the problem? >>>>>>> We hit this issue once more on the same server with Linux >>>>>>> 5.15.160, and had >>>>>>> to hard reboot it. >>>>>>> >>>>>>> Unfortunately we did not have time yet to set up a test system to >>>>>>> find a >>>>>>> reproducer. In our cases a lot of compute servers seem to have >>>>>>> accessed the >>>>>>> NFS server. A lot of the many processes were `zstd` on a first >>>>>>> glance. >>>>>> So we neither, due to the nature of the server (production system) >>>>>> and >>>>>> unability to reproduce the issue under some more controlled way >>>>>> and on >>>>>> test environment. >>>>>> >>>>>> In our case users seems to cause workloads involving use of wandb. >>>>>> >>>>>> What we tried is to boot the recent kernel from 5.10.y series >>>>>> avaiable >>>>>> (5.10.223-1). Then the issue showed up still. Since we disabled >>>>>> fs.leases-enable the situation seems to be more stable). While this >>>>>> is/might not be the solution, does that gives some additional hits? >>>>> The problem is backchannel-related, and disabling delegation >>>>> will reduce the number of backchannel operations. Your finding >>>>> comports with our current theory, but I can't think of how it >>>>> narrows the field of suspects. >>>>> >>>>> Is the server running short on memory, perhaps? One backchannel >>>>> operation that was added in v5.10.220 is CB_RECALL_ANY, which >>>>> is triggered on memory exhaustion. But that should be a fairly >>>>> harmless addition unless there is a bug in there somewhere. >>>>> >>>>> If your NFS server does not have any NFS mounts, then we could >>>>> provide instructions for enabling client-side tracing to watch >>>>> the details of callback traffic. >>>> The NFS server acts as well as NFS client, so tracing more >>>> back-channel related will I guess just load the tracing more. >>>> >>>> But we got "lucky" and we were able to trigger the issue twice in last >>>> days, once NFSv4 delegations were enabled again and some users started >>>> to cause more load on the specific server as well. >>>> >>>> I did issue >>>> >>>> rpcdebug -m rpc -c >>>> >>>> before rebooting/resetting the server which is >>>> >>>> Jan 30 05:27:05 nfsserver kernel: 26407 2281 -512 3d1fdb92 >>>> 0 0 79bc1aa5 nfs4_cbv1 CB_RECALL_ANY a:rpc_exit_task [sunrpc] >>>> q:delayq >>>> >>>> and the first RPC related soft lookup slapt in the log/journal I was >>>> able to gather is: >>>> >>>> Jan 29 22:34:05 nfsserver kernel: watchdog: BUG: soft lockup - >>>> CPU#11 stuck for 23s! [kworker/u42:3:705574] >>>> Jan 29 22:34:05 nfsserver kernel: Modules linked in: binfmt_misc >>>> rpcsec_gss_krb5 nfsv4 dns_resolver nfs fscache bonding quota_v2 >>>> quota_tree ipmi_ssif intel_rapl_msr intel_rapl_common skx_edac >>>> skx_edac_common nfit libnvdimm x86_pkg_temp_thermal intel_powerclamp >>>> coretemp kvm_intel kvm irqbypass ghash_clmulni_intel aesni_intel >>>> libaes crypto_simd cryptd ast glue_helper drm_vram_helper >>>> drm_ttm_helper rapl acpi_ipmi ttm iTCO_wdt intel_cstate ipmi_si >>>> intel_pmc_bxt drm_kms_helper mei_me iTCO_vendor_support ipmi_devintf >>>> cec ioatdma intel_uncore pcspkr evdev joydev sg i2c_algo_bit >>>> watchdog mei dca ipmi_msghandler acpi_power_meter acpi_pad button >>>> fuse drm configfs nfsd auth_rpcgss nfs_acl lockd grace sunrpc >>>> ip_tables x_tables autofs4 ext4 crc16 mbcache jbd2 raid10 raid456 >>>> async_raid6_recov async_memcpy async_pq async_xor async_tx xor >>>> raid6_pq libcrc32c crc32c_generic raid1 raid0 multipath linear >>>> md_mod dm_mod hid_generic usbhid hid sd_mod t10_pi crc_t10dif >>>> crct10dif_generic xhci_pci ahci xhci_hcd libahci i40e libata >>>> Jan 29 22:34:05 nfsserver kernel: crct10dif_pclmul arcmsr >>>> crct10dif_common ptp crc32_pclmul usbcore crc32c_intel scsi_mod >>>> pps_core i2c_i801 lpc_ich i2c_smbus wmi usb_common >>>> Jan 29 22:34:05 nfsserver kernel: CPU: 11 PID: 705574 Comm: kworker/ >>>> u42:3 Not tainted 5.10.0-33-amd64 #1 Debian 5.10.226-1 >>>> Jan 29 22:34:05 nfsserver kernel: Hardware name: DALCO AG S2600WFT/ >>>> S2600WFT, BIOS SE5C620.86B.02.01.0008.031920191559 03/19/2019 >>>> Jan 29 22:34:05 nfsserver kernel: Workqueue: rpciod >>>> rpc_async_schedule [sunrpc] >>>> Jan 29 22:34:05 nfsserver kernel: RIP: 0010:ktime_get+0x7b/0xa0 >>>> Jan 29 22:34:05 nfsserver kernel: Code: d1 e9 48 f7 d1 48 89 c2 48 >>>> 85 c1 8b 05 ae 2c a5 02 8b 0d ac 2c a5 02 48 0f 45 d5 8b 35 7e 2c a5 >>>> 02 41 39 f4 75 9e 48 0f af c2 <48> 01 f8 48 d3 e8 48 01 d8 5b 5d 41 >>>> 5c c3 cc cc cc cc f3 90 eb 84 >>>> Jan 29 22:34:05 nfsserver kernel: RSP: 0018:ffffa1aca9227e00 EFLAGS: >>>> 00000202 >>>> Jan 29 22:34:05 nfsserver kernel: RAX: 0000371a545e1910 RBX: >>>> 000005fce82a4372 RCX: 0000000000000018 >>>> Jan 29 22:34:05 nfsserver kernel: RDX: 000000000078efbe RSI: >>>> 000000000031f238 RDI: 00385c1353c92824 >>>> Jan 29 22:34:05 nfsserver kernel: RBP: 0000000000000000 R08: >>>> ffffffffc081f410 R09: ffffffffc081f410 >>>> Jan 29 22:34:05 nfsserver kernel: R10: 0000000000000003 R11: >>>> 0000000000000003 R12: 000000000031f238 >>>> Jan 29 22:34:05 nfsserver kernel: R13: ffff8ed42bf34830 R14: >>>> 0000000000000001 R15: 0000000000000000 >>>> Jan 29 22:34:05 nfsserver kernel: FS: 0000000000000000(0000) >>>> GS:ffff8ee94f880000(0000) knlGS:0000000000000000 >>>> Jan 29 22:34:05 nfsserver kernel: CS: 0010 DS: 0000 ES: 0000 CR0: >>>> 0000000080050033 >>>> Jan 29 22:34:05 nfsserver kernel: CR2: 00007ffddf306080 CR3: >>>> 00000017c420a002 CR4: 00000000007706e0 >>>> Jan 29 22:34:05 nfsserver kernel: DR0: 0000000000000000 DR1: >>>> 0000000000000000 DR2: 0000000000000000 >>>> Jan 29 22:34:05 nfsserver kernel: DR3: 0000000000000000 DR6: >>>> 00000000fffe0ff0 DR7: 0000000000000400 >>>> Jan 29 22:34:05 nfsserver kernel: PKRU: 55555554 >>>> Jan 29 22:34:05 nfsserver kernel: Call Trace: >>>> Jan 29 22:34:05 nfsserver kernel: <IRQ> >>>> Jan 29 22:34:05 nfsserver kernel: ? watchdog_timer_fn+0x1bb/0x210 >>>> Jan 29 22:34:05 nfsserver kernel: ? >>>> lockup_detector_update_enable+0x50/0x50 >>>> Jan 29 22:34:05 nfsserver kernel: ? __hrtimer_run_queues+0x127/0x280 >>>> Jan 29 22:34:05 nfsserver kernel: ? hrtimer_interrupt+0x110/0x2c0 >>>> Jan 29 22:34:05 nfsserver kernel: ? >>>> __sysvec_apic_timer_interrupt+0x5c/0xe0 >>>> Jan 29 22:34:05 nfsserver kernel: ? asm_call_irq_on_stack+0xf/0x20 >>>> Jan 29 22:34:05 nfsserver kernel: </IRQ> >>>> Jan 29 22:34:05 nfsserver kernel: ? >>>> sysvec_apic_timer_interrupt+0x72/0x80 >>>> Jan 29 22:34:05 nfsserver kernel: ? >>>> asm_sysvec_apic_timer_interrupt+0x12/0x20 >>>> Jan 29 22:34:05 nfsserver kernel: ? ktime_get+0x7b/0xa0 >>>> Jan 29 22:34:05 nfsserver kernel: rpc_exit_task+0x96/0x140 [sunrpc] >>>> Jan 29 22:34:05 nfsserver kernel: ? >>>> __rpc_do_wake_up_task_on_wq+0x1e0/0x1e0 [sunrpc] >>>> Jan 29 22:34:05 nfsserver kernel: __rpc_execute+0x6d/0x410 [sunrpc] >>>> Jan 29 22:34:05 nfsserver kernel: rpc_async_schedule+0x29/0x40 >>>> [sunrpc] >>>> Jan 29 22:34:05 nfsserver kernel: process_one_work+0x1b3/0x350 >>>> Jan 29 22:34:05 nfsserver kernel: worker_thread+0x53/0x3e0 >>>> Jan 29 22:34:05 nfsserver kernel: ? process_one_work+0x350/0x350 >>>> Jan 29 22:34:05 nfsserver kernel: kthread+0x118/0x140 >>>> Jan 29 22:34:05 nfsserver kernel: ? __kthread_bind_mask+0x60/0x60 >>>> Jan 29 22:34:05 nfsserver kernel: ret_from_fork+0x1f/0x30 >>>> >>>> I can try to pick on top of the kernel the change Chuck mentioned to >>>> me offlist, which is the posting of >>>> https://urldefense.com/v3/__https://lore.kernel.org/linux- >>>> nfs/1738271066-6727-1-git-send-email-dai.ngo@xxxxxxxxxx/__;!! >>>> ACWV5N9M2RV99hQ!ILxf31lSoNImIDh3FjDiD- >>>> qFRBH8gPEQhUW31gF2NOYGPFzPscgj7S23PoaBR1MFs6VLMprfKi9g6WdEkyY$ , >>>> and in fact this could be interesting. If the users keep doing the >>>> same kind of load, this might help understanding more the issue. >>>> >>>> As we suspect that the issue is more frequently triggered after the >>>> switch of 5.10.118 -> 5.10.221, this enforces more the above, which >>>> says it fixes 66af25799940 ("NFSD: add courteous server support for >>>> thread with only delegation"), which is in 5.19-rc1, but got >>>> backported to 5.15.154 and 5.10.220 as well. >>> Unfortunately not. The system ran slightly more stable with that >>> patch on, and >>> there was a nfsd hang inbeween here, within a series of >>> >>> [...] >>> Feb 02 03:22:40 nfsserver kernel: receive_cb_reply: Got unrecognized >>> reply: calldir 0x1 xpt_bc_xprt 00000000b31acdd9 xid 5d31fb84 >>> Feb 02 03:22:40 nfsserver kernel: receive_cb_reply: Got unrecognized >>> reply: calldir 0x1 xpt_bc_xprt 00000000ca92d20a xid 9ec25b24 >>> Feb 02 03:23:09 nfsserver kernel: receive_cb_reply: Got unrecognized >>> reply: calldir 0x1 xpt_bc_xprt 00000000ca92d20a xid 9fc25b24 >>> Feb 02 03:23:12 nfsserver kernel: receive_cb_reply: Got unrecognized >>> reply: calldir 0x1 xpt_bc_xprt 00000000b31acdd9 xid 5e31fb84 >>> Feb 02 03:23:24 nfsserver kernel: receive_cb_reply: Got unrecognized >>> reply: calldir 0x1 xpt_bc_xprt 00000000ca92d20a xid a0c25b24 >>> Feb 02 03:23:24 nfsserver kernel: receive_cb_reply: Got unrecognized >>> reply: calldir 0x1 xpt_bc_xprt 00000000b31acdd9 xid 5f31fb84 >>> Feb 02 03:23:31 nfsserver kernel: receive_cb_reply: Got unrecognized >>> reply: calldir 0x1 xpt_bc_xprt 00000000fe9013df xid 756103e9 >>> Feb 02 03:23:31 nfsserver kernel: receive_cb_reply: Got unrecognized >>> reply: calldir 0x1 xpt_bc_xprt 00000000471650a0 xid ef4f583e >>> Feb 02 03:23:33 nfsserver kernel: receive_cb_reply: Got unrecognized >>> reply: calldir 0x1 xpt_bc_xprt 000000008f30d648 xid 1ec77a2e >>> Feb 02 03:23:35 nfsserver kernel: receive_cb_reply: Got unrecognized >>> reply: calldir 0x1 xpt_bc_xprt 0000000035c718f5 xid d0b95b44 >>> Feb 02 03:27:43 nfsserver kernel: receive_cb_reply: Got unrecognized >>> reply: calldir 0x1 xpt_bc_xprt 00000000b31acdd9 xid 7d31fb84 >>> Feb 02 03:27:44 nfsserver kernel: receive_cb_reply: Got unrecognized >>> reply: calldir 0x1 xpt_bc_xprt 00000000ca92d20a xid bec25b24 >>> Feb 02 03:27:44 nfsserver kernel: receive_cb_reply: Got unrecognized >>> reply: calldir 0x1 xpt_bc_xprt 00000000f83dcedd xid e0be7eef >>> Feb 02 03:28:07 nfsserver kernel: receive_cb_reply: Got unrecognized >>> reply: calldir 0x1 xpt_bc_xprt 00000000ca92d20a xid bfc25b24 >>> Feb 02 03:28:09 nfsserver kernel: receive_cb_reply: Got unrecognized >>> reply: calldir 0x1 xpt_bc_xprt 00000000f83dcedd xid e1be7eef >>> Feb 02 03:31:41 nfsserver kernel: receive_cb_reply: Got unrecognized >>> reply: calldir 0x1 xpt_bc_xprt 000000004563c9e7 xid f96ccce2 >>> Feb 02 03:31:44 nfsserver kernel: receive_cb_reply: Got unrecognized >>> reply: calldir 0x1 xpt_bc_xprt 0000000035c718f5 xid 06ba5b44 >>> Feb 02 03:31:49 nfsserver kernel: receive_cb_reply: Got unrecognized >>> reply: calldir 0x1 xpt_bc_xprt 00000000b31acdd9 xid 9531fb84 >>> Feb 02 03:31:51 nfsserver kernel: receive_cb_reply: Got unrecognized >>> reply: calldir 0x1 xpt_bc_xprt 00000000f83dcedd xid f7be7eef >>> Feb 02 03:31:52 nfsserver kernel: receive_cb_reply: Got unrecognized >>> reply: calldir 0x1 xpt_bc_xprt 00000000471650a0 xid 2550583e >>> Feb 02 03:31:53 nfsserver kernel: receive_cb_reply: Got unrecognized >>> reply: calldir 0x1 xpt_bc_xprt 00000000ca92d20a xid d5c25b24 >>> Feb 02 03:31:53 nfsserver kernel: receive_cb_reply: Got unrecognized >>> reply: calldir 0x1 xpt_bc_xprt 00000000fe9013df xid ab6103e9 >>> Feb 02 03:31:53 nfsserver kernel: receive_cb_reply: Got unrecognized >>> reply: calldir 0x1 xpt_bc_xprt 000000004111342b xid 9da4f045 >>> Feb 02 03:32:32 nfsserver kernel: receive_cb_reply: Got unrecognized >>> reply: calldir 0x1 xpt_bc_xprt 00000000ca92d20a xid d8c25b24 >>> Feb 02 03:32:32 nfsserver kernel: receive_cb_reply: Got unrecognized >>> reply: calldir 0x1 xpt_bc_xprt 00000000f83dcedd xid fabe7eef >>> Feb 02 04:18:12 nfsserver kernel: receive_cb_reply: Got unrecognized >>> reply: calldir 0x1 xpt_bc_xprt 00000000ca92d20a xid a1c35b24 >>> Feb 02 04:18:12 nfsserver kernel: receive_cb_reply: Got unrecognized >>> reply: calldir 0x1 xpt_bc_xprt 000000009715512e xid 29a849e3 >>> Feb 02 04:18:13 nfsserver kernel: receive_cb_reply: Got unrecognized >>> reply: calldir 0x1 xpt_bc_xprt 00000000fe9013df xid 786203e9 >>> Feb 02 04:18:13 nfsserver kernel: receive_cb_reply: Got unrecognized >>> reply: calldir 0x1 xpt_bc_xprt 00000000471650a0 xid f150583e >>> Feb 02 04:18:13 nfsserver kernel: receive_cb_reply: Got unrecognized >>> reply: calldir 0x1 xpt_bc_xprt 000000004563c9e7 xid c66dcce2 >>> Feb 02 04:18:13 nfsserver kernel: receive_cb_reply: Got unrecognized >>> reply: calldir 0x1 xpt_bc_xprt 000000008f30d648 xid 21c87a2e >>> Feb 02 04:18:13 nfsserver kernel: receive_cb_reply: Got unrecognized >>> reply: calldir 0x1 xpt_bc_xprt 0000000053af79cb xid 49da29a2 >>> Feb 02 04:18:13 nfsserver kernel: receive_cb_reply: Got unrecognized >>> reply: calldir 0x1 xpt_bc_xprt 00000000b31acdd9 xid 6132fb84 >>> Feb 02 04:49:18 nfsserver kernel: receive_cb_reply: Got unrecognized >>> reply: calldir 0x1 xpt_bc_xprt 0000000035c718f5 xid 2ebb5b44 >>> Feb 02 04:49:21 nfsserver kernel: receive_cb_reply: Got unrecognized >>> reply: calldir 0x1 xpt_bc_xprt 000000004563c9e7 xid 226ecce2 >>> Feb 02 04:49:22 nfsserver kernel: receive_cb_reply: Got unrecognized >>> reply: calldir 0x1 xpt_bc_xprt 00000000ca92d20a xid fdc35b24 >>> Feb 02 04:49:22 nfsserver kernel: receive_cb_reply: Got unrecognized >>> reply: calldir 0x1 xpt_bc_xprt 00000000f83dcedd xid 1fc07eef >>> Feb 02 05:01:25 nfsserver kernel: receive_cb_reply: Got unrecognized >>> reply: calldir 0x1 xpt_bc_xprt 00000000ca92d20a xid 25c45b24 >>> Feb 02 05:09:27 nfsserver kernel: receive_cb_reply: Got unrecognized >>> reply: calldir 0x1 xpt_bc_xprt 00000000ca92d20a xid 51c45b24 >>> [...] >>> Feb 02 05:34:46 nfsserver kernel: INFO: task nfsd:1590 blocked for >>> more than 120 seconds. >>> Feb 02 05:34:46 nfsserver kernel: Tainted: G E >>> 5.10.0-34-amd64 #1 Debian 5.10.228-1~test1 >>> Feb 02 05:34:46 nfsserver kernel: "echo 0 > /proc/sys/kernel/ >>> hung_task_timeout_secs" disables this message. >>> Feb 02 05:34:46 nfsserver kernel: task:nfsd state:D >>> stack: 0 pid: 1590 ppid: 2 flags:0x00004000 >>> Feb 02 05:34:46 nfsserver kernel: Call Trace: >>> Feb 02 05:34:46 nfsserver kernel: __schedule+0x282/0x870 >>> Feb 02 05:34:46 nfsserver kernel: ? rwsem_spin_on_owner+0x74/0xd0 >>> Feb 02 05:34:46 nfsserver kernel: schedule+0x46/0xb0 >>> Feb 02 05:34:46 nfsserver kernel: rwsem_down_write_slowpath+0x257/0x4d0 >>> Feb 02 05:34:46 nfsserver kernel: ? trace_call_bpf+0x76/0xe0 >>> Feb 02 05:34:46 nfsserver kernel: ? nfsd4_write+0x1/0x1a0 [nfsd] >>> Feb 02 05:34:46 nfsserver kernel: >>> ext4_buffered_write_iter+0x33/0x160 [ext4] >>> Feb 02 05:34:46 nfsserver kernel: do_iter_readv_writev+0x14f/0x1b0 >>> Feb 02 05:34:46 nfsserver kernel: do_iter_write+0x80/0x1c0 >>> Feb 02 05:34:46 nfsserver kernel: nfsd_vfs_write+0x17f/0x680 [nfsd] >>> Feb 02 05:34:46 nfsserver kernel: nfsd4_write+0xd0/0x1a0 [nfsd] >>> Feb 02 05:34:46 nfsserver kernel: elfcorehdr_read+0x40/0x40 >>> Feb 02 05:34:46 nfsserver kernel: ? nfsd_dispatch+0x15b/0x250 [nfsd] >>> Feb 02 05:34:46 nfsserver kernel: ? svc_process_common+0x3e1/0x6e0 >>> [sunrpc] >>> Feb 02 05:34:46 nfsserver kernel: ? nfsd_svc+0x390/0x390 [nfsd] >>> Feb 02 05:34:46 nfsserver kernel: ? svc_process+0xb7/0xf0 [sunrpc] >>> Feb 02 05:34:46 nfsserver kernel: ? nfsd+0x91/0xb0 [nfsd] >>> Feb 02 05:34:46 nfsserver kernel: ? get_order+0x20/0x20 [nfsd] >>> Feb 02 05:34:46 nfsserver kernel: ? kthread+0x118/0x140 >>> Feb 02 05:34:46 nfsserver kernel: ? __kthread_bind_mask+0x60/0x60 >>> Feb 02 05:34:46 nfsserver kernel: ? ret_from_fork+0x1f/0x30 >>> Feb 02 05:34:46 nfsserver kernel: INFO: task nfsd:1599 blocked for >>> more than 120 seconds. >>> Feb 02 05:34:46 nfsserver kernel: Tainted: G E >>> 5.10.0-34-amd64 #1 Debian 5.10.228-1~test1 >>> Feb 02 05:34:46 nfsserver kernel: "echo 0 > /proc/sys/kernel/ >>> hung_task_timeout_secs" disables this message. >>> Feb 02 05:34:46 nfsserver kernel: task:nfsd state:D >>> stack: 0 pid: 1599 ppid: 2 flags:0x00004000 >>> Feb 02 05:34:46 nfsserver kernel: Call Trace: >>> Feb 02 05:34:46 nfsserver kernel: __schedule+0x282/0x870 >>> Feb 02 05:34:46 nfsserver kernel: ? rwsem_spin_on_owner+0x74/0xd0 >>> Feb 02 05:34:46 nfsserver kernel: schedule+0x46/0xb0 >>> Feb 02 05:34:46 nfsserver kernel: rwsem_down_write_slowpath+0x257/0x4d0 >>> Feb 02 05:34:46 nfsserver kernel: ? trace_call_bpf+0x76/0xe0 >>> Feb 02 05:34:46 nfsserver kernel: ? nfsd4_write+0x1/0x1a0 [nfsd] >>> Feb 02 05:34:46 nfsserver kernel: >>> ext4_buffered_write_iter+0x33/0x160 [ext4] >>> Feb 02 05:34:46 nfsserver kernel: do_iter_readv_writev+0x14f/0x1b0 >>> Feb 02 05:34:46 nfsserver kernel: do_iter_write+0x80/0x1c0 >>> Feb 02 05:34:46 nfsserver kernel: nfsd_vfs_write+0x17f/0x680 [nfsd] >>> Feb 02 05:34:46 nfsserver kernel: nfsd4_write+0xd0/0x1a0 [nfsd] >>> Feb 02 05:34:46 nfsserver kernel: elfcorehdr_read+0x40/0x40 >>> Feb 02 05:34:46 nfsserver kernel: ? nfsd_dispatch+0x15b/0x250 [nfsd] >>> Feb 02 05:34:46 nfsserver kernel: ? svc_process_common+0x3e1/0x6e0 >>> [sunrpc] >>> Feb 02 05:34:46 nfsserver kernel: ? nfsd_svc+0x390/0x390 [nfsd] >>> Feb 02 05:34:46 nfsserver kernel: ? svc_process+0xb7/0xf0 [sunrpc] >>> Feb 02 05:34:46 nfsserver kernel: ? nfsd+0x91/0xb0 [nfsd] >>> Feb 02 05:34:46 nfsserver kernel: ? get_order+0x20/0x20 [nfsd] >>> Feb 02 05:34:46 nfsserver kernel: ? kthread+0x118/0x140 >>> Feb 02 05:34:46 nfsserver kernel: ? __kthread_bind_mask+0x60/0x60 >>> Feb 02 05:34:46 nfsserver kernel: ? ret_from_fork+0x1f/0x30 >>> Feb 02 05:34:46 nfsserver kernel: INFO: task nfsd:1601 blocked for >>> more than 121 seconds. >>> Feb 02 05:34:46 nfsserver kernel: Tainted: G E >>> 5.10.0-34-amd64 #1 Debian 5.10.228-1~test1 >>> Feb 02 05:34:46 nfsserver kernel: "echo 0 > /proc/sys/kernel/ >>> hung_task_timeout_secs" disables this message. >>> Feb 02 05:34:46 nfsserver kernel: task:nfsd state:D >>> stack: 0 pid: 1601 ppid: 2 flags:0x00004000 >>> Feb 02 05:34:46 nfsserver kernel: Call Trace: >>> Feb 02 05:34:46 nfsserver kernel: __schedule+0x282/0x870 >>> Feb 02 05:34:46 nfsserver kernel: ? rwsem_spin_on_owner+0x74/0xd0 >>> Feb 02 05:34:46 nfsserver kernel: schedule+0x46/0xb0 >>> Feb 02 05:34:47 nfsserver kernel: rwsem_down_write_slowpath+0x257/0x4d0 >>> Feb 02 05:34:47 nfsserver kernel: ? trace_call_bpf+0x76/0xe0 >>> Feb 02 05:34:47 nfsserver kernel: ? nfsd4_write+0x1/0x1a0 [nfsd] >>> Feb 02 05:34:47 nfsserver kernel: >>> ext4_buffered_write_iter+0x33/0x160 [ext4] >>> Feb 02 05:34:47 nfsserver kernel: do_iter_readv_writev+0x14f/0x1b0 >>> Feb 02 05:34:47 nfsserver kernel: do_iter_write+0x80/0x1c0 >>> Feb 02 05:34:47 nfsserver kernel: nfsd_vfs_write+0x17f/0x680 [nfsd] >>> Feb 02 05:34:47 nfsserver kernel: nfsd4_write+0xd0/0x1a0 [nfsd] >>> Feb 02 05:34:47 nfsserver kernel: elfcorehdr_read+0x40/0x40 >>> Feb 02 05:34:47 nfsserver kernel: ? nfsd_dispatch+0x15b/0x250 [nfsd] >>> Feb 02 05:34:47 nfsserver kernel: ? svc_process_common+0x3e1/0x6e0 >>> [sunrpc] >>> Feb 02 05:34:47 nfsserver kernel: ? nfsd_svc+0x390/0x390 [nfsd] >>> Feb 02 05:34:47 nfsserver kernel: ? svc_process+0xb7/0xf0 [sunrpc] >>> Feb 02 05:34:47 nfsserver kernel: ? nfsd+0x91/0xb0 [nfsd] >>> Feb 02 05:34:47 nfsserver kernel: ? get_order+0x20/0x20 [nfsd] >>> Feb 02 05:34:47 nfsserver kernel: ? kthread+0x118/0x140 >>> Feb 02 05:34:47 nfsserver kernel: ? __kthread_bind_mask+0x60/0x60 >>> Feb 02 05:34:47 nfsserver kernel: ? ret_from_fork+0x1f/0x30 >>> Feb 02 05:34:47 nfsserver kernel: INFO: task nfsd:1604 blocked for >>> more than 121 seconds. >>> Feb 02 05:34:47 nfsserver kernel: Tainted: G E >>> 5.10.0-34-amd64 #1 Debian 5.10.228-1~test1 >>> Feb 02 05:34:47 nfsserver kernel: "echo 0 > /proc/sys/kernel/ >>> hung_task_timeout_secs" disables this message. >>> Feb 02 05:34:47 nfsserver kernel: task:nfsd state:D >>> stack: 0 pid: 1604 ppid: 2 flags:0x00004000 >>> Feb 02 05:34:47 nfsserver kernel: Call Trace: >>> Feb 02 05:34:47 nfsserver kernel: __schedule+0x282/0x870 >>> Feb 02 05:34:47 nfsserver kernel: ? rwsem_spin_on_owner+0x74/0xd0 >>> Feb 02 05:34:47 nfsserver kernel: schedule+0x46/0xb0 >>> Feb 02 05:34:47 nfsserver kernel: rwsem_down_write_slowpath+0x257/0x4d0 >>> Feb 02 05:34:47 nfsserver kernel: ? trace_call_bpf+0x76/0xe0 >>> Feb 02 05:34:47 nfsserver kernel: ? nfsd4_write+0x1/0x1a0 [nfsd] >>> Feb 02 05:34:47 nfsserver kernel: >>> ext4_buffered_write_iter+0x33/0x160 [ext4] >>> Feb 02 05:34:47 nfsserver kernel: do_iter_readv_writev+0x14f/0x1b0 >>> Feb 02 05:34:47 nfsserver kernel: do_iter_write+0x80/0x1c0 >>> Feb 02 05:34:47 nfsserver kernel: nfsd_vfs_write+0x17f/0x680 [nfsd] >>> Feb 02 05:34:47 nfsserver kernel: nfsd4_write+0xd0/0x1a0 [nfsd] >>> Feb 02 05:34:47 nfsserver kernel: elfcorehdr_read+0x40/0x40 >>> Feb 02 05:34:47 nfsserver kernel: ? nfsd_dispatch+0x15b/0x250 [nfsd] >>> Feb 02 05:34:47 nfsserver kernel: ? svc_process_common+0x3e1/0x6e0 >>> [sunrpc] >>> Feb 02 05:34:47 nfsserver kernel: ? nfsd_svc+0x390/0x390 [nfsd] >>> Feb 02 05:34:47 nfsserver kernel: ? svc_process+0xb7/0xf0 [sunrpc] >>> Feb 02 05:34:47 nfsserver kernel: ? nfsd+0x91/0xb0 [nfsd] >>> Feb 02 05:34:47 nfsserver kernel: ? get_order+0x20/0x20 [nfsd] >>> Feb 02 05:34:47 nfsserver kernel: ? kthread+0x118/0x140 >>> Feb 02 05:34:47 nfsserver kernel: ? __kthread_bind_mask+0x60/0x60 >>> Feb 02 05:34:47 nfsserver kernel: ? ret_from_fork+0x1f/0x30 >>> Feb 02 05:34:47 nfsserver kernel: INFO: task nfsd:1610 blocked for >>> more than 121 seconds. >>> Feb 02 05:34:47 nfsserver kernel: Tainted: G E >>> 5.10.0-34-amd64 #1 Debian 5.10.228-1~test1 >>> Feb 02 05:34:47 nfsserver kernel: "echo 0 > /proc/sys/kernel/ >>> hung_task_timeout_secs" disables this message. >>> Feb 02 05:34:47 nfsserver kernel: task:nfsd state:D >>> stack: 0 pid: 1610 ppid: 2 flags:0x00004000 >>> Feb 02 05:34:47 nfsserver kernel: Call Trace: >>> Feb 02 05:34:47 nfsserver kernel: __schedule+0x282/0x870 >>> Feb 02 05:34:47 nfsserver kernel: schedule+0x46/0xb0 >>> Feb 02 05:34:47 nfsserver kernel: rwsem_down_write_slowpath+0x257/0x4d0 >>> Feb 02 05:34:47 nfsserver kernel: ? trace_call_bpf+0x76/0xe0 >>> Feb 02 05:34:47 nfsserver kernel: ? nfsd4_write+0x1/0x1a0 [nfsd] >>> Feb 02 05:34:47 nfsserver kernel: >>> ext4_buffered_write_iter+0x33/0x160 [ext4] >>> Feb 02 05:34:47 nfsserver kernel: do_iter_readv_writev+0x14f/0x1b0 >>> Feb 02 05:34:47 nfsserver kernel: do_iter_write+0x80/0x1c0 >>> Feb 02 05:34:47 nfsserver kernel: nfsd_vfs_write+0x17f/0x680 [nfsd] >>> Feb 02 05:34:47 nfsserver kernel: nfsd4_write+0xd0/0x1a0 [nfsd] >>> Feb 02 05:34:47 nfsserver kernel: elfcorehdr_read+0x40/0x40 >>> Feb 02 05:34:47 nfsserver kernel: ? nfsd_dispatch+0x15b/0x250 [nfsd] >>> Feb 02 05:34:47 nfsserver kernel: ? svc_process_common+0x3e1/0x6e0 >>> [sunrpc] >>> Feb 02 05:34:47 nfsserver kernel: ? nfsd_svc+0x390/0x390 [nfsd] >>> Feb 02 05:34:47 nfsserver kernel: ? svc_process+0xb7/0xf0 [sunrpc] >>> Feb 02 05:34:47 nfsserver kernel: ? nfsd+0x91/0xb0 [nfsd] >>> Feb 02 05:34:47 nfsserver kernel: ? get_order+0x20/0x20 [nfsd] >>> Feb 02 05:34:47 nfsserver kernel: ? kthread+0x118/0x140 >>> Feb 02 05:34:47 nfsserver kernel: ? __kthread_bind_mask+0x60/0x60 >>> Feb 02 05:34:47 nfsserver kernel: ? ret_from_fork+0x1f/0x30 >> This is a totally different failure mode: it's hanging in the >> ext4 write path. One of your nfsd threads is stuck in D state >> waiting to get a rw semaphor. >> >> Question is, who is holding that rw_sem and why? >> >> >>> This happend a couple of times again and "recovered", but got finally >>> stuck >>> again with: >>> >>> Feb 02 10:55:25 nfsserver kernel: receive_cb_reply: Got unrecognized >>> reply: calldir 0x1 xpt_bc_xprt 00000000b31acdd9 xid 1639fb84 >>> Feb 02 10:55:26 nfsserver kernel: receive_cb_reply: Got unrecognized >>> reply: calldir 0x1 xpt_bc_xprt 000000004111342b xid 24acf045 >>> Feb 02 10:55:27 nfsserver kernel: receive_cb_reply: Got unrecognized >>> reply: calldir 0x1 xpt_bc_xprt 0000000035c718f5 xid 89c15b44 >>> Feb 02 10:55:28 nfsserver kernel: receive_cb_reply: Got unrecognized >>> reply: calldir 0x1 xpt_bc_xprt 000000004563c9e7 xid 8c74cce2 >>> Feb 02 10:55:50 nfsserver kernel: rcu: INFO: rcu_sched self-detected >>> stall on CPU >>> Feb 02 10:55:50 nfsserver kernel: rcu: 14-....: (5249 ticks >>> this GP) idle=c4e/1/0x4000000000000000 softirq=3120573/3120573 fqs=2624 >>> Feb 02 10:55:50 nfsserver kernel: (t=5250 jiffies g=4585625 >>> q=145785) >>> Feb 02 10:55:50 nfsserver kernel: NMI backtrace for cpu 14 >>> Feb 02 10:55:50 nfsserver kernel: CPU: 14 PID: 614435 Comm: kworker/ >>> u42:2 Tainted: G E 5.10.0-34-amd64 #1 Debian >>> 5.10.228-1~test1 >>> Feb 02 10:55:50 nfsserver kernel: Hardware name: DALCO AG S2600WFT/ >>> S2600WFT, BIOS SE5C620.86B.02.01.0008.031920191559 03/19/2019 >>> Feb 02 10:55:50 nfsserver kernel: Workqueue: rpciod >>> rpc_async_schedule [sunrpc] >>> Feb 02 10:55:50 nfsserver kernel: Call Trace: >>> Feb 02 10:55:50 nfsserver kernel: <IRQ> >>> Feb 02 10:55:50 nfsserver kernel: dump_stack+0x6b/0x83 >>> Feb 02 10:55:50 nfsserver kernel: nmi_cpu_backtrace.cold+0x32/0x69 >>> Feb 02 10:55:50 nfsserver kernel: ? lapic_can_unplug_cpu+0x80/0x80 >>> Feb 02 10:55:50 nfsserver kernel: >>> nmi_trigger_cpumask_backtrace+0xdb/0xf0 >>> Feb 02 10:55:50 nfsserver kernel: rcu_dump_cpu_stacks+0xa5/0xd7 >>> Feb 02 10:55:50 nfsserver kernel: rcu_sched_clock_irq.cold+0x202/0x3d9 >>> Feb 02 10:55:50 nfsserver kernel: ? timekeeping_advance+0x370/0x5c0 >>> Feb 02 10:55:50 nfsserver kernel: update_process_times+0x8c/0xc0 >>> Feb 02 10:55:50 nfsserver kernel: tick_sched_handle+0x22/0x60 >>> Feb 02 10:55:50 nfsserver kernel: tick_sched_timer+0x65/0x80 >>> Feb 02 10:55:50 nfsserver kernel: ? tick_sched_do_timer+0x90/0x90 >>> Feb 02 10:55:50 nfsserver kernel: __hrtimer_run_queues+0x127/0x280 >>> Feb 02 10:55:50 nfsserver kernel: hrtimer_interrupt+0x110/0x2c0 >>> Feb 02 10:55:50 nfsserver kernel: >>> __sysvec_apic_timer_interrupt+0x5c/0xe0 >>> Feb 02 10:55:50 nfsserver kernel: asm_call_irq_on_stack+0xf/0x20 >>> Feb 02 10:55:50 nfsserver kernel: </IRQ> >>> Feb 02 10:55:50 nfsserver kernel: sysvec_apic_timer_interrupt+0x72/0x80 >>> Feb 02 10:55:50 nfsserver kernel: >>> asm_sysvec_apic_timer_interrupt+0x12/0x20 >>> Feb 02 10:55:50 nfsserver kernel: RIP: >>> 0010:mod_delayed_work_on+0x5d/0x90 >>> Feb 02 10:55:50 nfsserver kernel: Code: 00 4c 89 e7 e8 34 fe ff ff 89 >>> c3 83 f8 f5 74 e9 85 c0 78 1b 89 ef 4c 89 f1 4c 89 e2 4c 89 ee e8 f9 >>> fc ff ff 48 8b 3c 24 57 9d <0f> 1f 44 00 00 85 db 0f 95 c0 48 8b 4c >>> 24 08 65 48 2b 0c 25 28 00 >>> Feb 02 10:55:50 nfsserver kernel: RSP: 0018:ffffaaff25d57d90 EFLAGS: >>> 00000246 >>> Feb 02 10:55:50 nfsserver kernel: RAX: 0000000000000000 RBX: >>> 0000000000000000 RCX: 000000003e60000e >>> Feb 02 10:55:50 nfsserver kernel: RDX: 000000003e400000 RSI: >>> 0000000000000046 RDI: 0000000000000246 >>> Feb 02 10:55:50 nfsserver kernel: RBP: 0000000000002000 R08: >>> ffffffffc08f6430 R09: ffffffffc08f6448 >>> Feb 02 10:55:50 nfsserver kernel: R10: 0000000000000003 R11: >>> 0000000000000003 R12: ffffffffc08f6428 >>> Feb 02 10:55:50 nfsserver kernel: R13: ffff8e4083a4b400 R14: >>> 00000000000001f4 R15: 0000000000000000 >>> Feb 02 10:55:50 nfsserver kernel: >>> __rpc_sleep_on_priority_timeout+0x111/0x120 [sunrpc] >>> Feb 02 10:55:50 nfsserver kernel: rpc_delay+0x56/0x90 [sunrpc] >>> Feb 02 10:55:50 nfsserver kernel: rpc_exit_task+0x5a/0x140 [sunrpc] >>> Feb 02 10:55:50 nfsserver kernel: ? >>> __rpc_do_wake_up_task_on_wq+0x1e0/0x1e0 [sunrpc] >>> Feb 02 10:55:50 nfsserver kernel: __rpc_execute+0x6d/0x410 [sunrpc] >>> Feb 02 10:55:50 nfsserver kernel: rpc_async_schedule+0x29/0x40 [sunrpc] >>> Feb 02 10:55:50 nfsserver kernel: process_one_work+0x1b3/0x350 >>> Feb 02 10:55:50 nfsserver kernel: worker_thread+0x53/0x3e0 >>> Feb 02 10:55:50 nfsserver kernel: ? process_one_work+0x350/0x350 >>> Feb 02 10:55:50 nfsserver kernel: kthread+0x118/0x140 >>> Feb 02 10:55:50 nfsserver kernel: ? __kthread_bind_mask+0x60/0x60 >>> Feb 02 10:55:50 nfsserver kernel: ret_from_fork+0x1f/0x30 >>> >>> Before rebooting the system, rpcdebug -m rpc -c was issued again, >>> with the >>> following logged entry: >>> >>> Feb 02 11:01:52 nfsserver kernel: -pid- flgs status -client- --rqstp- >>> -timeout ---ops-- >>> Feb 02 11:01:52 nfsserver kernel: 42135 2281 0 8ff8d038 >>> 0 500 1a6bcc0 nfs4_cbv1 CB_RECALL_ANY a:call_start [sunrpc] q:none >> This is also different: the CB_RECALL_ANY is waiting to start, it's not >> retransmitting. > > When CB_RECALL_ANY is returned with cb_seq_status == 1, it is restarted > by nfsd4_cb_sequence_done. Restarting means the callback is re-queued in > nfsd4_cb_release which schedules a new work to re-send the callback. So > the 'call_start' status could indicate that the CB_RECALL_ANY is being > resending in a loop. True, but I was looking at the "q:none". If CB_RECALL_ANY were retransmitting due to NFS4ERR_DELAY, which I've seen in past rpc_show_tasks output, that would be "q:delayq". >>> The system is now again back booted with fs.leases-enable=0 to keep >>> it more >>> "stable". >> Understood, but I don't yet see how this new scenario is related to >> NFSv4 delegation. We can speculate, but here's nothing standing out in >> the collected data. >> >> -- Chuck Lever
