watchdog: BUG: soft lockup - CPU#0 stuck for 187s! [ksoftirqd/0:7] about linux HOT 3 CLOSED

[ 1745.900000] watchdog: BUG: soft lockup - CPU#0 stuck for 184s! [ksoftirqd/0:7]
[ 1745.900000] Modules linked in:
[ 1745.900000] CPU: 0 PID: 7 Comm: ksoftirqd/0 Tainted: G             L    5.5.0-simple-smp #91
[ 1745.900000] CPU #: 0
[ 1745.900000]    PC: c006c1dc    SR: 0000867f    SP: c1025c68
[ 1745.900000] GPR00: 00000000 GPR01: c1025c68 GPR02: c1025c8c GPR03: 00000000
[ 1745.900000] GPR04: ffffffff GPR05: 00000018 GPR06: c8000000 GPR07: 14090495
[ 1745.900000] GPR08: 000003ca GPR09: c006c1a0 GPR10: c1024000 GPR11: 00000000
[ 1745.900000] GPR12: 218aa635 GPR13: 00000000 GPR14: 048e4000 GPR15: 00000000
[ 1745.900000] GPR16: c0910c50 GPR17: eb8937dd GPR18: a0000000 GPR19: 00000001
[ 1745.900000] GPR20: 5cc049da GPR21: 00000007 GPR22: 00000168 GPR23: 00000468
[ 1745.900000] GPR24: 0000001a GPR25: 00000010 GPR26: 00041b08 GPR27: 0000000e
[ 1745.900000] GPR28: 008ad419 GPR29: 00000012 GPR30: 00000200 GPR31: c1e35d70
[ 1745.900000]   RES: 00000000 oGPR11: ffffffff
[ 1745.900000] Process ksoftirqd/0 (pid: 7, stackpage=c101b400)
[ 1745.900000]
[ 1745.900000] Stack:
[ 1745.900000] Call trace:
[ 1745.900000] [<5344f851>] ktime_get+0x70/0x1bc
[ 1745.900000] [<88164d97>] tcp_mstamp_refresh+0x30/0x190
[ 1745.900000] [<497cf51c>] tcp_rcv_established+0x38/0x798
[ 1745.900000] [<1447d5c1>] tcp_v4_do_rcv+0x1e4/0x238
[ 1745.900000] [<21cdc523>] tcp_v4_rcv+0xd1c/0xdd0
[ 1745.900000] [<f65863ef>] ? __inet_lookup_established+0x6c/0x248
[ 1745.900000] [<278b79da>] ip_protocol_deliver_rcu+0x44/0x1e8
[ 1745.900000] [<7bb669e4>] ip_local_deliver+0xa4/0xf8
[ 1745.900000] [<3e703180>] ip_rcv+0x6c/0xa0
[ 1745.900000] [<cf154ebe>] __netif_receive_skb_one_core+0x50/0x68
[ 1745.900000] [<7a0f7052>] __netif_receive_skb+0x38/0x98
[ 1745.900000] [<72f95335>] netif_receive_skb+0x38/0x90
[ 1745.900000] [<9b4bb2ad>] ethoc_poll+0x280/0x900
[ 1745.900000] [<917ada6e>] net_rx_action+0x11c/0x3cc
[ 1745.900000] [<6554ac93>] ? mempool_kfree+0x14/0x24
[ 1745.900000] [<e4702a67>] __do_softirq+0x128/0x320
[ 1745.900000] [<0edefd55>] ? smpboot_thread_fn+0x0/0x26c
[ 1745.900000] [<ddaf11a2>] run_ksoftirqd+0x50/0x70
[ 1745.900000] [<6abd7f59>] smpboot_thread_fn+0x1b8/0x26c
[ 1745.900000] [<e436cf21>] ? __kthread_parkme+0x68/0xa8
[ 1745.900000] [<410cfcab>] kthread+0x120/0x150
[ 1745.900000] [<12695f1f>] ? kthread+0x0/0x150
[ 1745.900000] [<161c3108>] ret_from_fork+0x1c/0x9c

/ # [  467.110000] watchdog: BUG: soft lockup - CPU#0 stuck for 186s! [find:58]
[  467.110000] Modules linked in:
[  467.110000] CPU: 0 PID: 58 Comm: find Not tainted 5.5.0-simple-smp #92
[  467.110000] CPU #: 0
[  467.110000]    PC: c03aa6e0    SR: 00008a7f    SP: c15c9b9c
[  467.110000] GPR00: 00000000 GPR01: c15c9b9c GPR02: c15c9bc0 GPR03: 00000000
[  467.110000] GPR04: eb89c0b0 GPR05: 00000000 GPR06: c8000000 GPR07: 00000000
[  467.110000] GPR08: c1693da8 GPR09: c006c1f4 GPR10: c15c8000 GPR11: fffffffe
[  467.110000] GPR12: 2d2452f4 GPR13: 00000000 GPR14: fffff41a GPR15: c1d3ee24
[  467.110000] GPR16: c0910c50 GPR17: eb89c0b0 GPR18: e0000000 GPR19: 00000001
[  467.110000] GPR20: 8efcc1f6 GPR21: 00000001 GPR22: 0000003e GPR23: 00000002
[  467.110000] GPR24: 0000001a GPR25: 00000000 GPR26: 0000cc58 GPR27: 00000002
[  467.110000] GPR28: 00ca2a16 GPR29: 000000be GPR30: 04000000 GPR31: 00000070
[  467.110000]   RES: fffffffe oGPR11: ffffffff
[  467.110000] Process find (pid: 58, stackpage=c156ef00)
[  467.110000]
[  467.110000] Stack:
[  467.110000] Call trace:
[  467.110000] [<8725bbff>] ktime_get+0x70/0x1bc
[  467.110000] [<ddad94d4>] rpc_count_iostats_metrics+0x44/0x2c4
[  467.110000] [<979d7fad>] rpc_count_iostats+0x28/0x38
[  467.110000] [<3c8007c1>] rpc_exit_task+0xd4/0xdc
[  467.110000] [<47c3421c>] ? rpc_exit_task+0x0/0xdc
[  467.110000] [<cbb3ebda>] __rpc_execute+0x94/0x3d0
[  467.110000] [<9d21a225>] rpc_execute+0x7c/0x94
[  467.110000] [<d7c83a27>] rpc_run_task+0x174/0x210
[  467.110000] [<819a9673>] rpc_call_sync+0x60/0xec
[  467.110000] [<992b5c96>] nfs3_rpc_wrapper.constprop.0+0x40/0xb0
[  467.110000] [<7f5680f6>] nfs3_proc_readdir+0xc4/0x108
[  467.110000] [<507e9d06>] nfs_readdir_xdr_to_array+0x16c/0x450
[  467.110000] [<9cf27540>] nfs_readdir_filler+0x2c/0x130
[  467.110000] [<aa1ecec4>] ? add_to_page_cache_lru+0xd8/0x18c
[  467.110000] [<a0d28eba>] do_read_cache_page+0x384/0x8d8
[  467.110000] [<31603d34>] ? path_openat+0x430/0x1660
[  467.110000] [<afaccdde>] ? nfs_readdir_filler+0x0/0x130
[  467.110000] [<f645d472>] ? nfs_check_cache_invalid+0x3c/0x120
[  467.110000] [<afaccdde>] ? nfs_readdir_filler+0x0/0x130
[  467.110000] [<e793fb51>] ? _s_kernel_ro+0x0/0x200
[  467.110000] [<56422074>] read_cache_page+0x18/0x28
[  467.110000] [<fa63a6cf>] nfs_readdir+0x1c4/0x790
[  467.110000] [<abb2e645>] ? do_filp_open+0x78/0xf8
[  467.110000] [<59f83342>] ? nfs3_decode_dirent+0x0/0x3ac
[  467.110000] [<979eee08>] iterate_dir+0xb4/0x204
[  467.110000] [<1b213b35>] ksys_getdents64+0x90/0x184
[  467.110000] [<b60ef5a0>] ? filldir64+0x0/0x1f4
[  467.110000] [<e100fafd>] sys_getdents64+0x14/0x24
[  467.110000] [<16e5e94f>] ? _syscall_return+0x0/0x4

/ # uptime
 20:47:24 up 3 days, 5 min,  0 users,  load average: 0.08, 0.01, 0.00
/ # uname -a
Linux openrisc 5.7.0-rc2-simple-smp-00001-g8d2d00a72c37-dirty #105 Thu Apr 23 05:41:46 JST 2020 openrisc GNU/Linux
/ # free -m
             total       used       free     shared    buffers     cached
Mem:           500         80        419          6          0         13
-/+ buffers/cache:         67        433
Swap:            0          0          0