[BUG REPORT] softlock up in sunrpc xprt_end_transmit

From: jiangheng (G)
Date: Sat Apr 08 2023 - 08:59:31 EST


Hi all,
on linux 5.10, When we performed a pressure test on the nfs, a soft lock appeared in the sunrpc. The call stack is as follows::

[ 9101.352822] nfs: Unknown parameter 'time'
[ 9101.352866] nfs: Unknown parameter 'time'
[ 9101.352897] nfs: Unknown parameter 'time'
[ 9101.371096] nfs: Unknown parameter 'time'
[ 9113.565686] WARN: soft lockup - CPU#0 stuck for 11s! [mount.nfs:416907] [ 9113.566231] Sample time: 9113152707554 ns(HZ: 250) [ 9113.566232] Sample stat:
[ 9113.566235] curr: user: 704341612740, nice: 147841070, sys: 3534402945130, idle: 4282970293860, iowait: 490295074600, irq: 42190618900, softirq: 58359875870, st: 0 [ 9113.566237] deta: user: 704341612740, nice: 147841070, sys: 3534402945130, idle: 4282970293860, iowait: 490295074600, irq: 42190618900, softirq: 58359875870, st: 0 [ 9113.566237] Sample softirq:
[ 9113.566239] TIMER: 529280
[ 9113.566240] NET_TX: 1796
[ 9113.566241] NET_RX: 919176
[ 9113.566242] BLOCK: 2853203
[ 9113.566243] TASKLET: 39177
[ 9113.566244] SCHED: 1127611
[ 9113.566245] HRTIMER: 7
[ 9113.566246] RCU: 3058196
[ 9113.566247] Sample irqstat:
[ 9113.566249] irq 1: delta 4574226, curr: 4574226, IPI
[ 9113.566250] irq 2: delta 93760, curr: 93760, IPI
[ 9113.566253] irq 12: delta 2337685, curr: 2337685, arch_timer
[ 9113.566262] irq 48: delta 51, curr: 51, ehci_hcd:usb1
[ 9113.566265] irq 53: delta 1, curr: 1, PCIe PME
[ 9113.566267] irq 57: delta 1, curr: 1, PCIe PME
[ 9113.566269] irq 61: delta 6, curr: 6, PCIe PME
[ 9113.566271] irq 65: delta 6, curr: 6, PCIe PME
[ 9113.566273] irq 69: delta 6, curr: 6, PCIe PME
[ 9113.566276] irq 73: delta 6, curr: 6, PCIe PME
[ 9113.566279] irq 81: delta 18528, curr: 18528, virtio2-input.0
[ 9113.566281] irq 82: delta 665654, curr: 665654, virtio2-output.0
[ 9113.566284] irq 87: delta 153505, curr: 153505, virtio4-input.0
[ 9113.566286] irq 90: delta 12792, curr: 12792, virtio1-control
[ 9113.566288] irq 94: delta 2, curr: 2, virtio5-event
[ 9113.566290] irq 95: delta 3017695, curr: 3017695, virtio5-request
[ 9113.566295] CPU: 0 PID: 416907 Comm: mount.nfs Kdump: loaded Tainted: G O 5.10.0-60.18.0.50.h734.eulerosv2r11.aarch64 #1
[ 9113.566296] Hardware name: QEMU KVM Virtual Machine, BIOS 0.0.0 02/06/2015 [ 9113.566298] Call trace:
[ 9113.566304] dump_backtrace+0x0/0x1e4 [ 9113.566307] show_stack+0x20/0x2c [ 9113.566313] dump_stack+0xd8/0x140 [ 9113.566315] watchdog_print_info+0x48/0x54 [ 9113.566318] watchdog_process_before_softlockup+0x98/0xa0
[ 9113.566319] watchdog_timer_fn+0x1ac/0x2d0 [ 9113.566322] __run_hrtimer+0x98/0x2a0 [ 9113.566323] __hrtimer_run_queues+0xbc/0x130 [ 9113.566325] hrtimer_interrupt+0x13c/0x3c0 [ 9113.566330] arch_timer_handler_virt+0x3c/0x50 [ 9113.566332] handle_percpu_devid_irq+0x90/0x1f4
[ 9113.566335] generic_handle_irq+0x58/0x70 [ 9113.566336] __handle_domain_irq+0x6c/0xe0 [ 9113.566338] gic_handle_irq+0x88/0x2b0 [ 9113.566340] el1_irq+0xb8/0x140 [ 9113.566388] xprt_reserve_xprt_cong+0x58/0x1c0 [sunrpc] [ 9113.566407] xprt_prepare_transmit+0xb0/0x110 [sunrpc] [ 9113.566426] call_transmit+0x34/0xb4 [sunrpc] [ 9113.566444] __rpc_execute+0x74/0x400 [sunrpc] [ 9113.566462] rpc_execute+0x68/0x90 [sunrpc] [ 9113.566479] rpc_run_task+0x98/0x110 [sunrpc] [ 9113.566497] rpc_call_sync+0x64/0xc4 [sunrpc] [ 9113.566529] nfs_mount+0x114/0x27c [nfs] [ 9113.566543] nfs_request_mount.constprop.0.isra.0+0xd0/0x1d4 [nfs] [ 9113.566555] nfs_try_mount_request+0x54/0x2bc [nfs] [ 9113.566566] nfs_try_get_tree+0x58/0xec [nfs] [ 9113.566577] nfs_get_tree+0x44/0x6c [nfs] [ 9113.566582] vfs_get_tree+0x30/0xf4 [ 9113.566585] do_new_mount+0x16c/0x1e0 [ 9113.566587] path_mount+0x1bc/0x2c0 [ 9113.566589] __arm64_sys_mount+0x114/0x140 [ 9113.566591] el0_svc_common.constprop.0+0x7c/0x1bc
[ 9113.566592] do_el0_svc+0x2c/0x94
[ 9113.566595] el0_svc+0x20/0x30
[ 9113.566597] el0_sync_handler+0xb0/0xb4 [ 9113.566608] el0_sync+0x160/0x180 [ 9125.566258] watchdog: BUG: soft lockup - CPU#0 stuck for 22s! [mount.nfs:416907] [ 9125.566871] Modules linked in: kbox(O) kboxdriver(O) sch_netem nfsv3 nfs_acl cts rpcsec_gss_krb5 auth_rpcgss nfsv4 dns_resolver nfs lockd grace nfs_ssc fscache xfs binfmt_misc nft_fib_inet nft_fib_ipv4 nft_fib_ipv6 nft_fib nft_reject_inet nf_reject_ipv4 nf_reject_ipv6 nft_reject nft_ct nft_chain_nat nf_tables ebtable_nat ebtable_broute ip6table_nat ip6table_mangle ip6table_raw ip6table_security iptable_nat nf_nat nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 libcrc32c iptable_mangle iptable_raw iptable_security rfkill ip_set nfnetlink ebtable_filter ebtables ip6table_filter ip6_tables iptable_filter ip_tables sysmonitor(O) sunrpc sg vfat fat sch_fq_codel fuse ksecurec(O) ext4 mbcache jbd2 sd_mod t10_pi virtio_scsi virtio_gpu ghash_ce sha2_ce virtio_net net_failover failover virtio_console virtio_dma_buf sha256_arm64 sha1_ce virtio_pci virtio_mmio virtio_ring virtio dm_mirror dm_region_hash dm_log dm_mod aes_neon_bs aes_neon_blk aes_ce_blk crypto_simd cryptd aes_ce_cipher [ 9125.566963] [last unloaded: kboxdriver] [ 9125.566967] Sample time: 9125152869899 ns(HZ: 250) [ 9125.566968] Sample stat:
[ 9125.566971] curr: user: 704341612740, nice: 147841070, sys: 3546387321660, idle: 4282970293860, iowait: 490295074600, irq: 42206243200, softirq: 58359875870, st: 0 [ 9125.566973] deta: user: 704341612740, nice: 147841070, sys: 3546387321660, idle: 4282970293860, iowait: 490295074600, irq: 42206243200, softirq: 58359875870, st: 0 [ 9125.566974] Sample softirq:
[ 9125.566976] TIMER: 529280
[ 9125.566977] NET_TX: 1796
[ 9125.566978] NET_RX: 919176
[ 9125.566978] BLOCK: 2853203
[ 9125.566979] TASKLET: 39177
[ 9125.566981] SCHED: 1127611
[ 9125.566981] HRTIMER: 7
[ 9125.566982] RCU: 3058196
[ 9125.566984] Sample irqstat:
[ 9125.566986] irq 1: delta 4574226, curr: 4574226, IPI
[ 9125.566987] irq 2: delta 93760, curr: 93760, IPI
[ 9125.566990] irq 12: delta 2340688, curr: 2340688, arch_timer
[ 9125.566999] irq 48: delta 51, curr: 51, ehci_hcd:usb1
[ 9125.567002] irq 53: delta 1, curr: 1, PCIe PME
[ 9125.567004] irq 57: delta 1, curr: 1, PCIe PME
[ 9125.567006] irq 61: delta 6, curr: 6, PCIe PME
[ 9125.567008] irq 65: delta 6, curr: 6, PCIe PME
[ 9125.567010] irq 69: delta 6, curr: 6, PCIe PME
[ 9125.567012] irq 73: delta 6, curr: 6, PCIe PME
[ 9125.567016] irq 81: delta 18528, curr: 18528, virtio2-input.0
[ 9125.567018] irq 82: delta 665654, curr: 665654, virtio2-output.0
[ 9125.567019] irq 84: delta 1, curr: 1, virtio3-input.0
[ 9125.567022] irq 87: delta 153505, curr: 153505, virtio4-input.0
[ 9125.567024] irq 90: delta 12792, curr: 12792, virtio1-control
[ 9125.567026] irq 94: delta 2, curr: 2, virtio5-event
[ 9125.567028] irq 95: delta 3017696, curr: 3017696, virtio5-request
[ 9125.567032] CPU: 0 PID: 416907 Comm: mount.nfs Kdump: loaded Tainted: G O 5.10.0-60.18.0.50.h734.eulerosv2r11.aarch64 #1
[ 9125.567034] Hardware name: QEMU KVM Virtual Machine, BIOS 0.0.0 02/06/2015 [ 9125.567036] pstate: 60400005 (nZCv daif +PAN -UAO -TCO BTYPE=--) [ 9125.567080] pc : xprt_end_transmit+0xb8/0x124 [sunrpc] [ 9125.567100] lr : call_transmit+0xa4/0xb4 [sunrpc] [ 9125.567101] sp : ffff80010aa83910 [ 9125.567102] x29: ffff80010aa83910 x28: ffff00004aaf2680 [ 9125.567105] x27: 0000000000000000 x26: ffff8001017a2098 [ 9125.567107] x25: 0000000000000000 x24: ffff80010143d008 [ 9125.567109] x23: ffff80010143d008 x22: ffff0000d3fa7690 [ 9125.567111] x21: ffff800081033210 x20: ffff0000591d8c00 [ 9125.567113] x19: ffff0000d3fa7000 x18: 0000000000000000 [ 9125.567116] x17: 0000000000000000 x16: ffff800100b08770 [ 9125.567118] x15: 0000000000000004 x14: ffff8001017d49f0 [ 9125.567120] x13: 0000000000000000 x12: 0000000000000030 [ 9125.567122] x11: 0000000000000000 x10: 0000000000000001 [ 9125.567124] x9 : ffff8000810332b4 x8 : ffffffffffffff9b [ 9125.567126] x7 : 0000000000000001 x6 : 0000000000000000 [ 9125.567128] x5 : 00007dffc1b5e988 x4 : 0000000000000000 [ 9125.567130] x3 : 0000000000000000 x2 : 0000000000000001 [ 9125.567132] x1 : 0000000000000000 x0 : ffff0000d3fa7690 [ 9125.567135] Call trace:
[ 9125.567156] xprt_end_transmit+0xb8/0x124 [sunrpc] [ 9125.567174] call_transmit+0xa4/0xb4 [sunrpc] [ 9125.567193] __rpc_execute+0x74/0x400 [sunrpc] [ 9125.567210] rpc_execute+0x68/0x90 [sunrpc] [ 9125.567228] rpc_run_task+0x98/0x110 [sunrpc] [ 9125.567246] rpc_call_sync+0x64/0xc4 [sunrpc] [ 9125.567278] nfs_mount+0x114/0x27c [nfs] [ 9125.567291] nfs_request_mount.constprop.0.isra.0+0xd0/0x1d4 [nfs] [ 9125.567302] nfs_try_mount_request+0x54/0x2bc [nfs] [ 9125.567314] nfs_try_get_tree+0x58/0xec [nfs] [ 9125.567325] nfs_get_tree+0x44/0x6c [nfs] [ 9125.567330] vfs_get_tree+0x30/0xf4 [ 9125.567334] do_new_mount+0x16c/0x1e0 [ 9125.567335] path_mount+0x1bc/0x2c0 [ 9125.567337] __arm64_sys_mount+0x114/0x140 [ 9125.567340] el0_svc_common.constprop.0+0x7c/0x1bc
[ 9125.567341] do_el0_svc+0x2c/0x94
[ 9125.567346] el0_svc+0x20/0x30
[ 9125.567348] el0_sync_handler+0xb0/0xb4 [ 9125.567350] el0_sync+0x160/0x180 [ 9125.567352] [kbox] catch rlock event on cpu 0, rlock reason:SOFT-WATCHDOG detected!
[ 9125.567356] [kbox] catch rlock event, start logging [ 9125.567359] [kbox] start to collect [ 9125.577001] [kbox] collected_len = 1177956, g_printk_tmp_log_buf_len = 3145728 [ 9125.581540] [kbox] save kbox pre log success [ 9125.581648] cpu 0 will send nmi ,the cpumask = 0xe
[ 9125.582281] CPU: 1 PID: 0 Comm: swapper/1 Kdump: loaded Tainted: G O 5.10.0-60.18.0.50.h734.eulerosv2r11.aarch64 #1
[ 9125.582291] Hardware name: QEMU KVM Virtual Machine, BIOS 0.0.0 02/06/2015 [ 9125.582293] Call trace:
[ 9125.582294] dump_backtrace+0x0/0x1e4 [ 9125.582295] show_stack+0x20/0x2c [ 9125.582296] dump_stack+0xd8/0x140 [ 9125.582297] kbox_print_cpus_trace+0x40/0x80 [kbox] [ 9125.582298] do_handle_IPI+0xe0/0x39c [ 9125.582300] ipi_handler+0x24/0x34 [ 9125.582301] handle_percpu_devid_fasteoi_ipi+0x84/0x14c
[ 9125.582302] generic_handle_irq+0x58/0x70 [ 9125.582303] __handle_domain_irq+0x6c/0xe0 [ 9125.582304] gic_handle_irq+0x88/0x2b0 [ 9125.582305] el1_irq+0xb8/0x140 [ 9125.582307] arch_cpu_idle+0x18/0x40 [ 9125.582308] default_idle_call+0x5c/0x1c0 [ 9125.582309] cpuidle_idle_call+0x174/0x1b0 [ 9125.582310] do_idle+0x158/0x160 [ 9125.582312] cpu_startup_entry+0x30/0x11c [ 9125.582313] secondary_start_kernel+0x158/0x1e4
[ 9125.582314] Sample time: 9125168142009 ns(HZ: 250) [ 9125.582315] Sample stat:
[ 9125.582317] curr: user: 724776295090, nice: 94351110, sys: 3910489195840, idle: 3888847397680, iowait: 515238314120, irq: 29777149630, softirq: 55571481180, st: 0 [ 9125.582319] deta: user: 724776295090, nice: 94351110, sys: 3910489195840, idle: 3888847397680, iowait: 515238314120, irq: 29777149630, softirq: 55571481180, st: 0 [ 9125.582320] Sample softirq:
[ 9125.582321] HI: 2
[ 9125.582322] TIMER: 345066
[ 9125.582324] NET_TX: 173
[ 9125.582325] NET_RX: 2015738
[ 9125.582325] TASKLET: 57022
[ 9125.582327] SCHED: 920420
[ 9125.582328] RCU: 2689429
[ 9125.582329] Sample irqstat:
[ 9125.582330] irq 1: delta 1822068, curr: 1822068, IPI
[ 9125.582332] irq 2: delta 88326, curr: 88326, IPI
[ 9125.582333] irq 9: delta 1, curr: 1, IPI
[ 9125.582334] irq 12: delta 2301385, curr: 2301385, arch_timer
[ 9125.582335] irq 82: delta 902667, curr: 902667, virtio2-output.0
[ 9125.582337] irq 84: delta 670719, curr: 670719, virtio3-input.0
[ 9125.582338] irq 87: delta 431234, curr: 431234, virtio4-input.0
[ 9125.582340] irq 90: delta 19335, curr: 19335, virtio1-control
[ 9125.582341] irq 94: delta 1, curr: 1, virtio5-event
[ 9125.582344] CPU: 3 PID: 0 Comm: swapper/3 Kdump: loaded Tainted: G O 5.10.0-60.18.0.50.h734.eulerosv2r11.aarch64 #1
[ 9125.582352] Hardware name: QEMU KVM Virtual Machine, BIOS 0.0.0 02/06/2015 [ 9125.582353] Call trace:
[ 9125.582354] dump_backtrace+0x0/0x1e4 [ 9125.582355] show_stack+0x20/0x2c [ 9125.582357] dump_stack+0xd8/0x140 [ 9125.582358] kbox_print_cpus_trace+0x40/0x80 [kbox] [ 9125.582359] do_handle_IPI+0xe0/0x39c [ 9125.582360] ipi_handler+0x24/0x34 [ 9125.582361] handle_percpu_devid_fasteoi_ipi+0x84/0x14c
[ 9125.582362] generic_handle_irq+0x58/0x70 [ 9125.582364] __handle_domain_irq+0x6c/0xe0 [ 9125.582365] gic_handle_irq+0x88/0x2b0 [ 9125.582366] el1_irq+0xb8/0x140 [ 9125.582367] arch_cpu_idle+0x18/0x40 [ 9125.582369] default_idle_call+0x5c/0x1c0 [ 9125.582370] cpuidle_idle_call+0x174/0x1b0 [ 9125.582371] do_idle+0x158/0x160 [ 9125.582372] cpu_startup_entry+0x30/0x11c [ 9125.582373] secondary_start_kernel+0x158/0x1e4
[ 9125.582374] Sample time: 9125168110050 ns(HZ: 250) [ 9125.582376] Sample stat:
[ 9125.582377] curr: user: 729739797980, nice: 101548160, sys: 4045500121700, idle: 3966440313580, iowait: 282109642230, irq: 31591894520, softirq: 69408276750, st: 0 [ 9125.582380] deta: user: 729739797980, nice: 101548160, sys: 4045500121700, idle: 3966440313580, iowait: 282109642230, irq: 31591894520, softirq: 69408276750, st: 0 [ 9125.582381] Sample softirq:
[ 9125.582383] TIMER: 268844
[ 9125.582384] NET_TX: 267
[ 9125.582385] NET_RX: 2728023
[ 9125.582386] TASKLET: 20056
[ 9125.582387] SCHED: 877073
[ 9125.582388] HRTIMER: 91
[ 9125.582449] RCU: 2498916
[ 9125.582451] Sample irqstat:
[ 9125.582452] irq 1: delta 1704591, curr: 1704591, IPI
[ 9125.582453] irq 2: delta 87703, curr: 87703, IPI
[ 9125.582455] irq 9: delta 1, curr: 1, IPI
[ 9125.582456] irq 12: delta 2299208, curr: 2299208, arch_timer
[ 9125.582457] irq 81: delta 438039, curr: 438039, virtio2-input.0
[ 9125.582459] irq 82: delta 257442, curr: 257442, virtio2-output.0
[ 9125.582460] irq 84: delta 966776, curr: 966776, virtio3-input.0
[ 9125.582461] irq 87: delta 1039695, curr: 1039695, virtio4-input.0
[ 9125.582463] irq 90: delta 9832, curr: 9832, virtio1-control
[ 9125.582467] CPU: 2 PID: 0 Comm: swapper/2 Kdump: loaded Tainted: G O 5.10.0-60.18.0.50.h734.eulerosv2r11.aarch64 #1
[ 9125.582471] Hardware name: QEMU KVM Virtual Machine, BIOS 0.0.0 02/06/2015 [ 9125.582472] Call trace:
[ 9125.582474] dump_backtrace+0x0/0x1e4 [ 9125.582475] show_stack+0x20/0x2c [ 9125.582476] dump_stack+0xd8/0x140 [ 9125.582477] kbox_print_cpus_trace+0x40/0x80 [kbox] [ 9125.582478] do_handle_IPI+0xe0/0x39c [ 9125.582479] ipi_handler+0x24/0x34 [ 9125.582480] handle_percpu_devid_fasteoi_ipi+0x84/0x14c
[ 9125.582481] generic_handle_irq+0x58/0x70 [ 9125.582482] __handle_domain_irq+0x6c/0xe0 [ 9125.582483] gic_handle_irq+0x88/0x2b0 [ 9125.582485] el1_irq+0xb8/0x140 [ 9125.582486] arch_cpu_idle+0x18/0x40 [ 9125.582487] default_idle_call+0x5c/0x1c0 [ 9125.582488] cpuidle_idle_call+0x174/0x1b0 [ 9125.582489] do_idle+0x158/0x160 [ 9125.582490] cpu_startup_entry+0x30/0x11c [ 9125.582491] secondary_start_kernel+0x158/0x1e4
[ 9125.582492] Sample time: 9125168182397 ns(HZ: 250) [ 9125.582494] Sample stat:
[ 9125.582495] curr: user: 728729600830, nice: 143816300, sys: 3880725560230, idle: 4130118023190, iowait: 232349647860, irq: 32197515740, softirq: 120481741950, st: 0 [ 9125.582497] deta: user: 728729600830, nice: 143816300, sys: 3880725560230, idle: 4130118023190, iowait: 232349647860, irq: 32197515740, softirq: 120481741950, st: 0 [ 9125.582499] Sample softirq:
[ 9125.582500] HI: 2
[ 9125.582501] TIMER: 350970
[ 9125.582502] NET_TX: 30906
[ 9125.582503] NET_RX: 3266744
[ 9125.582504] TASKLET: 21378
[ 9125.582505] SCHED: 913487
[ 9125.582506] HRTIMER: 39
[ 9125.582507] RCU: 2598774
[ 9125.582508] Sample irqstat:
[ 9125.582509] irq 1: delta 1565956, curr: 1565956, IPI
[ 9125.582510] irq 2: delta 82113, curr: 82113, IPI
[ 9125.582512] irq 9: delta 1, curr: 1, IPI
[ 9125.582513] irq 12: delta 2334079, curr: 2334079, arch_timer
[ 9125.582514] irq 55: delta 1, curr: 1, PCIe PME
[ 9125.582516] irq 59: delta 1, curr: 1, PCIe PME
[ 9125.582517] irq 63: delta 6, curr: 6, PCIe PME
[ 9125.582518] irq 67: delta 6, curr: 6, PCIe PME
[ 9125.582519] irq 71: delta 6, curr: 6, PCIe PME
[ 9125.582520] irq 75: delta 6, curr: 6, PCIe PME
[ 9125.582521] irq 79: delta 1, curr: 1, virtio0-virtqueues
[ 9125.582523] irq 81: delta 3030056, curr: 3030056, virtio2-input.0
[ 9125.582524] irq 82: delta 218431, curr: 218431, virtio2-output.0
[ 9125.582525] irq 87: delta 15354, curr: 15354, virtio4-input.0
[ 9125.582527] irq 90: delta 2384, curr: 2384, virtio1-control
[ 9126.617943] smp_nmi_call_function:async mode, i finished!
[ 9126.617950] smp_nmi_call_function:this time is running cpumask = 0x0 [ 9126.638135] [kbox] cpu1 nmi buf len=0, continue [ 9126.638136] [kbox] cpu2 nmi buf len=0, continue [ 9126.638137] [kbox] cpu3 nmi buf len=0, continue [ 9126.651305] [kbox] notify die begin [ 9126.651308] [kbox] no notify die func register. no need to notify [ 9126.651323] Kernel panic - not syncing: softlockup: hung tasks
[ 9126.651330] CPU: 0 PID: 416907 Comm: mount.nfs Kdump: loaded Tainted: G O L 5.10.0-60.18.0.50.h734.eulerosv2r11.aarch64 #1
[ 9126.651331] Hardware name: QEMU KVM Virtual Machine, BIOS 0.0.0 02/06/2015 [ 9126.651334] Call trace:
[ 9126.651340] dump_backtrace+0x0/0x1e4 [ 9126.651343] show_stack+0x20/0x2c [ 9126.651349] dump_stack+0xd8/0x140 [ 9126.651350] panic+0x220/0x4d0 [ 9126.651354] watchdog_timer_fn+0x26c/0x2d0 [ 9126.651356] __run_hrtimer+0x98/0x2a0 [ 9126.651358] __hrtimer_run_queues+0xbc/0x130 [ 9126.651359] hrtimer_interrupt+0x13c/0x3c0 [ 9126.651364] arch_timer_handler_virt+0x3c/0x50 [ 9126.651366] handle_percpu_devid_irq+0x90/0x1f4
[ 9126.651369] generic_handle_irq+0x58/0x70 [ 9126.651371] __handle_domain_irq+0x6c/0xe0 [ 9126.651373] gic_handle_irq+0x88/0x2b0 [ 9126.651374] el1_irq+0xb8/0x140 [ 9126.651421] xprt_end_transmit+0xb8/0x124 [sunrpc] [ 9126.651440] call_transmit+0xa4/0xb4 [sunrpc] [ 9126.651459] __rpc_execute+0x74/0x400 [sunrpc] [ 9126.651477] rpc_execute+0x68/0x90 [sunrpc] [ 9126.651495] rpc_run_task+0x98/0x110 [sunrpc] [ 9126.651513] rpc_call_sync+0x64/0xc4 [sunrpc] [ 9126.651545] nfs_mount+0x114/0x27c [nfs] [ 9126.651558] nfs_request_mount.constprop.0.isra.0+0xd0/0x1d4 [nfs] [ 9126.651570] nfs_try_mount_request+0x54/0x2bc [nfs] [ 9126.651582] nfs_try_get_tree+0x58/0xec [nfs] [ 9126.651594] nfs_get_tree+0x44/0x6c [nfs] [ 9126.651598] vfs_get_tree+0x30/0xf4 [ 9126.651601] do_new_mount+0x16c/0x1e0 [ 9126.651603] path_mount+0x1bc/0x2c0 [ 9126.651605] __arm64_sys_mount+0x114/0x140 [ 9126.651607] el0_svc_common.constprop.0+0x7c/0x1bc
[ 9126.651608] do_el0_svc+0x2c/0x94
[ 9126.651611] el0_svc+0x20/0x30
[ 9126.651613] el0_sync_handler+0xb0/0xb4 [ 9126.651614] el0_sync+0x160/0x180 [ 9126.651617] kernel fault(0x5) notification starting on CPU 0 [ 9126.651618] kernel fault(0x5) notification finished on CPU 0 [ 9126.651619] SMP: stopping secondary CPUs [ 9126.651676] [kbox] catch panic event, panic reason:softlockup: hung tasks [ 9126.651679] [kbox] rlock event has been record!
[ 9126.651679] [kbox] notify die begin
[ 9126.651680] [kbox] no notify die func register. no need to notify [ 9126.651682] [kbox] end panic event [ 9126.651684] Kernel Offset: disabled [ 9126.651686] CPU features: 0x0000,88000002,2a208038 [ 9126.651687] Memory Limit: none [ 9126.653439] Starting crashdump kernel...
[ 9126.653446] Bye!


Crash:bt -l
#0 [ffff800102c3bb50] __crash_kexec at ffff8001001c2248
/usr/src/debug/kernel-5.10.0-60.18.0.50.h734.eulerosv2r11.aarch64/linux-5.10.0-60.18.0.50.h734.eulerosv2r11.aarch64/./arch/arm64/include/asm/kexec.h: 57
#1 [ffff800102c3bce0] panic at ffff800100d2bf4c
/usr/src/debug/kernel-5.10.0-60.18.0.50.h734.eulerosv2r11.aarch64/linux-5.10.0-60.18.0.50.h734.eulerosv2r11.aarch64/kernel/panic.c: 382
#2 [ffff800102c3bdd0] watchdog_timer_fn at ffff80010020baa8
/usr/src/debug/kernel-5.10.0-60.18.0.50.h734.eulerosv2r11.aarch64/linux-5.10.0-60.18.0.50.h734.eulerosv2r11.aarch64/kernel/watchdog.c: 574
#3 [ffff800102c3be20] __run_hrtimer at ffff800100192ed8
/usr/src/debug/kernel-5.10.0-60.18.0.50.h734.eulerosv2r11.aarch64/linux-5.10.0-60.18.0.50.h734.eulerosv2r11.aarch64/kernel/time/hrtimer.c: 1586
#4 [ffff800102c3be70] __hrtimer_run_queues at ffff80010019319c
/usr/src/debug/kernel-5.10.0-60.18.0.50.h734.eulerosv2r11.aarch64/linux-5.10.0-60.18.0.50.h734.eulerosv2r11.aarch64/kernel/time/hrtimer.c: 1650
#5 [ffff800102c3bed0] hrtimer_interrupt at ffff8001001937d8
/usr/src/debug/kernel-5.10.0-60.18.0.50.h734.eulerosv2r11.aarch64/linux-5.10.0-60.18.0.50.h734.eulerosv2r11.aarch64/kernel/time/hrtimer.c: 1712
#6 [ffff800102c3bf40] arch_timer_handler_virt at ffff800100aab3c8
/usr/src/debug/kernel-5.10.0-60.18.0.50.h734.eulerosv2r11.aarch64/linux-5.10.0-60.18.0.50.h734.eulerosv2r11.aarch64/drivers/clocksource/arm_arch_timer.c: 674
#7 [ffff800102c3bf50] handle_percpu_devid_irq at ffff80010016598c
/usr/src/debug/kernel-5.10.0-60.18.0.50.h734.eulerosv2r11.aarch64/linux-5.10.0-60.18.0.50.h734.eulerosv2r11.aarch64/./arch/arm64/include/asm/percpu.h: 45
#8 [ffff800102c3bf80] generic_handle_irq at ffff80010015b3d4
/usr/src/debug/kernel-5.10.0-60.18.0.50.h734.eulerosv2r11.aarch64/linux-5.10.0-60.18.0.50.h734.eulerosv2r11.aarch64/./include/linux/irqdesc.h: 154
#9 [ffff800102c3bf90] __handle_domain_irq at ffff80010015c318
/usr/src/debug/kernel-5.10.0-60.18.0.50.h734.eulerosv2r11.aarch64/linux-5.10.0-60.18.0.50.h734.eulerosv2r11.aarch64/kernel/irq/irqdesc.c: 699
#10 [ffff800102c3bfd0] gic_handle_irq at ffff800100010144
/usr/src/debug/kernel-5.10.0-60.18.0.50.h734.eulerosv2r11.aarch64/linux-5.10.0-60.18.0.50.h734.eulerosv2r11.aarch64/./include/linux/irqdesc.h: 172
--- <IRQ stack> ---
#11 [ffff80010aa838f0] el1_irq at ffff800100012374
/usr/src/debug/kernel-5.10.0-60.18.0.50.h734.eulerosv2r11.aarch64/linux-5.10.0-60.18.0.50.h734.eulerosv2r11.aarch64/arch/arm64/kernel/entry.S: 672
#12 [ffff80010aa83910] xprt_end_transmit at ffff80008103a234 [sunrpc]
/usr/src/debug/kernel-5.10.0-60.18.0.50.h734.eulerosv2r11.aarch64/linux-5.10.0-60.18.0.50.h734.eulerosv2r11.aarch64/./arch/arm64/include/asm/atomic_lse.h: 370
#13 [ffff80010aa83940] call_transmit at ffff8000810332b0 [sunrpc]
/usr/src/debug/kernel-5.10.0-60.18.0.50.h734.eulerosv2r11.aarch64/linux-5.10.0-60.18.0.50.h734.eulerosv2r11.aarch64/net/sunrpc/clnt.c: 2151
#14 [ffff80010aa83960] __rpc_execute at ffff800081053f80 [sunrpc]
/usr/src/debug/kernel-5.10.0-60.18.0.50.h734.eulerosv2r11.aarch64/linux-5.10.0-60.18.0.50.h734.eulerosv2r11.aarch64/net/sunrpc/sched.c: 894
#15 [ffff80010aa839b0] rpc_execute at ffff800081054694 [sunrpc]
/usr/src/debug/kernel-5.10.0-60.18.0.50.h734.eulerosv2r11.aarch64/linux-5.10.0-60.18.0.50.h734.eulerosv2r11.aarch64/net/sunrpc/sched.c: 971
#16 [ffff80010aa839d0] rpc_run_task at ffff800081034844 [sunrpc]
/usr/src/debug/kernel-5.10.0-60.18.0.50.h734.eulerosv2r11.aarch64/linux-5.10.0-60.18.0.50.h734.eulerosv2r11.aarch64/net/sunrpc/clnt.c: 1147
#17 [ffff80010aa839f0] rpc_call_sync at ffff8000810349e0 [sunrpc]
/usr/src/debug/kernel-5.10.0-60.18.0.50.h734.eulerosv2r11.aarch64/linux-5.10.0-60.18.0.50.h734.eulerosv2r11.aarch64/net/sunrpc/clnt.c: 1176
#18 [ffff80010aa83a70] nfs_mount at ffff8000814c51b4 [nfs]
/usr/src/debug/kernel-5.10.0-60.18.0.50.h734.eulerosv2r11.aarch64/linux-5.10.0-60.18.0.50.h734.eulerosv2r11.aarch64/fs/nfs/mount_clnt.c: 189
#19 [ffff80010aa83b70] nfs_request_mount.constprop.0 at ffff8000814b4e4c [nfs]
/usr/src/debug/kernel-5.10.0-60.18.0.50.h734.eulerosv2r11.aarch64/linux-5.10.0-60.18.0.50.h734.eulerosv2r11.aarch64/fs/nfs/super.c: 851
#20 [ffff80010aa83bf0] nfs_try_mount_request at ffff8000814b4fa4 [nfs]
/usr/src/debug/kernel-5.10.0-60.18.0.50.h734.eulerosv2r11.aarch64/linux-5.10.0-60.18.0.50.h734.eulerosv2r11.aarch64/fs/nfs/super.c: 872

The above backtrace seems to be caused by the lock (xprt->transport_lock). According to the code review, it seems that the same thread is repeatedly locked(xprt->transport_lock):
xprt_prepare_transmit
xprt_lock_write
spin_lock(&xprt->transport_lock);
xprt->ops->reserve_xprt --> xprt_reserve_xprt_cong
spin_unlock(&xprt->transport_lock);

xprt_reserve_xprt_cong
out_sleep:
rpc_sleep_check_activated(task)
if !RPC_IS_ACTIVATED(task)
rpc_put_task_async
...
xprt_release
spin_lock(&xprt->transport_lock);

I wonder if softlockup is due to the above code? When softlockup is occurs, NFS is repeatedly mounted, and is difficult to reproduce.
Please help analyze the possible causes of this.