On Sun, 2025-02-02 at 11:18 -0500, 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://lore.kernel.org/linux-nfs/1738271066-6727-1-git-send-email-dai.ngo@xxxxxxxxxx/, > > > 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? > > It looks like ext4_buffered_write_iter() takes the inode_lock, so it's probably the inode->i_rwsem that it's waiting on. Unfortunately all sorts of things take that lock so it's hard to speculate about the cause of it being stuck. Consider triggering a sysrq-w if this occurs again, which would tell us something about the contended locks. > > 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 mod_delayed_work_on() disables IRQs and then calls down into the workqueue code to modify a wq job. If that took too long then you'd see an rcu_sched warning like this. > > 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. > > > > > 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. > > Agreed. It looks like there are bigger issues than just nfsd here. -- Jeff Layton <jlayton@xxxxxxxxxx>
