also happened on ublk testing,
dmesg log:
[ 1633.771149] Dev: ublk-loop Engine: libaio Sched: mq-deadline
Pattern: randrw Depth: 16 Fstype: xfs
[ 1679.077461] restraintd[1501]: *** Current Time: Thu Aug 07 11:58:26
2025 Localwatchdog at: Thu Aug 07 16:33:25 2025
[ 1726.950887]
[ 1726.952567] ======================================================
[ 1726.959479] WARNING: possible circular locking dependency detected
[ 1726.966390] 6.16.0+ #1 Tainted: G S
[ 1726.971939] ------------------------------------------------------
[ 1726.978841] bash/1709 is trying to acquire lock:
[ 1726.984000] ffffffff9e345790 (pcpu_alloc_mutex){+.+.}-{4:4}, at:
pcpu_alloc_noprof+0x8a3/0xd50
[ 1726.993638]
[ 1726.993638] but task is already holding lock:
[ 1727.000151] ff110001d6026f98 (&q->elevator_lock){+.+.}-{4:4}, at:
elevator_change+0x12d/0x500
[ 1727.009684]
[ 1727.009684] which lock already depends on the new lock.
[ 1727.009684]
[ 1727.018814]
[ 1727.018814] the existing dependency chain (in reverse order) is:
[ 1727.027170]
[ 1727.027170] -> #3 (&q->elevator_lock){+.+.}-{4:4}:
[ 1727.034176] __lock_acquire+0x57c/0xbd0
[ 1727.039045] lock_acquire.part.0+0xbd/0x260
[ 1727.044300] __mutex_lock+0x1a9/0x1b20
[ 1727.049075] elevator_change+0x12d/0x500
[ 1727.054037] elv_iosched_store+0x27b/0x2f0
[ 1727.059196] queue_attr_store+0x22f/0x2f0
[ 1727.064260] kernfs_fop_write_iter+0x3a0/0x5a0
[ 1727.069808] vfs_write+0x525/0xfd0
[ 1727.074192] ksys_write+0xf9/0x1d0
[ 1727.078572] do_syscall_64+0x94/0x8d0
[ 1727.083248] entry_SYSCALL_64_after_hwframe+0x76/0x7e
[ 1727.089474]
[ 1727.089474] -> #2 (&q->q_usage_counter(io)#9){++++}-{0:0}:
[ 1727.097259] __lock_acquire+0x57c/0xbd0
[ 1727.102125] lock_acquire.part.0+0xbd/0x260
[ 1727.107381] blk_alloc_queue+0x5ca/0x710
[ 1727.112345] blk_mq_alloc_queue+0x14b/0x230
[ 1727.117601] __blk_mq_alloc_disk+0x18/0xd0
[ 1727.122761] ublk_ctrl_start_dev.isra.0+0x6eb/0xdd0 [ublk_drv]
[ 1727.129862] ublk_ctrl_uring_cmd+0x6f3/0x1390 [ublk_drv]
[ 1727.136381] io_uring_cmd+0x18e/0x490
[ 1727.141056] __io_issue_sqe+0xaa/0x7d0
[ 1727.145830] io_issue_sqe+0x80/0xe20
[ 1727.150406] io_wq_submit_work+0x2c0/0xe40
[ 1727.155563] io_worker_handle_work+0x429/0x780
[ 1727.161110] io_wq_worker+0x2f2/0xab0
[ 1727.165781] ret_from_fork+0x390/0x480
[ 1727.170554] ret_from_fork_asm+0x1a/0x30
[ 1727.175518]
[ 1727.175518] -> #1 (fs_reclaim){+.+.}-{0:0}:
[ 1727.181838] __lock_acquire+0x57c/0xbd0
[ 1727.186704] lock_acquire.part.0+0xbd/0x260
[ 1727.191957] fs_reclaim_acquire+0xc9/0x110
[ 1727.197117] __kmalloc_noprof+0xba/0x5e0
[ 1727.202083] pcpu_alloc_chunk+0x24/0x3e0
[ 1727.207049] pcpu_create_chunk+0x12/0x350
[ 1727.212110] pcpu_alloc_noprof+0xaa8/0xd50
[ 1727.217269] bts_init+0x139/0x1e0
[ 1727.221557] do_one_initcall+0xa4/0x260
[ 1727.226424] do_initcalls+0x1b4/0x1f0
[ 1727.231095] kernel_init_freeable+0x4a8/0x520
[ 1727.236542] kernel_init+0x1c/0x150
[ 1727.241022] ret_from_fork+0x390/0x480
[ 1727.245793] ret_from_fork_asm+0x1a/0x30
[ 1727.250758]
[ 1727.250758] -> #0 (pcpu_alloc_mutex){+.+.}-{4:4}:
[ 1727.257668] check_prev_add+0xf1/0xcd0
[ 1727.262438] validate_chain+0x487/0x570
[ 1727.267304] __lock_acquire+0x57c/0xbd0
[ 1727.272169] lock_acquire.part.0+0xbd/0x260
[ 1727.277423] __mutex_lock+0x1a9/0x1b20
[ 1727.282195] pcpu_alloc_noprof+0x8a3/0xd50
[ 1727.287354] kyber_queue_data_alloc+0x16d/0x610
[ 1727.292998] kyber_init_sched+0x18/0xa0
[ 1727.297864] blk_mq_init_sched+0x26e/0x4e0
[ 1727.303021] elevator_switch+0x1ae/0x650
[ 1727.307986] elevator_change+0x2db/0x500
[ 1727.312949] elv_iosched_store+0x27b/0x2f0
[ 1727.318105] queue_attr_store+0x22f/0x2f0
[ 1727.323168] kernfs_fop_write_iter+0x3a0/0x5a0
[ 1727.328714] vfs_write+0x525/0xfd0
[ 1727.333099] ksys_write+0xf9/0x1d0
[ 1727.337479] do_syscall_64+0x94/0x8d0
[ 1727.342150] entry_SYSCALL_64_after_hwframe+0x76/0x7e
[ 1727.348374]
[ 1727.348374] other info that might help us debug this:
[ 1727.348374]
[ 1727.357312] Chain exists of:
[ 1727.357312] pcpu_alloc_mutex --> &q->q_usage_counter(io)#9 -->
&q->elevator_lock
[ 1727.357312]
[ 1727.370624] Possible unsafe locking scenario:
[ 1727.370624]
[ 1727.377233] CPU0 CPU1
[ 1727.382293] ---- ----
[ 1727.387352] lock(&q->elevator_lock);
[ 1727.391542] lock(&q->q_usage_counter(io)#9);
[ 1727.399323] lock(&q->elevator_lock);
[ 1727.406323] lock(pcpu_alloc_mutex);
[ 1727.410414]
[ 1727.410414] *** DEADLOCK ***
[ 1727.410414]
[ 1727.417014] 7 locks held by bash/1709:
[ 1727.421200] #0: ff110001e9420448 (sb_writers#4){.+.+}-{0:0}, at:
ksys_write+0xf9/0x1d0
[ 1727.430152] #1: ff110001d6771490 (&of->mutex#2){+.+.}-{4:4}, at:
kernfs_fop_write_iter+0x260/0x5a0
[ 1727.440268] #2: ff110001e2d41270 (kn->active#105){.+.+}-{0:0}, at:
kernfs_fop_write_iter+0x283/0x5a0
[ 1727.450579] #3: ff11000120e161f8
(&set->update_nr_hwq_lock){.+.+}-{4:4}, at:
elv_iosched_store+0x1dc/0x2f0
[ 1727.461469] #4: ff110001d6026a00
(&q->q_usage_counter(io)#9){++++}-{0:0}, at:
blk_mq_freeze_queue_nomemsave+0x12/0x20
[ 1727.473417] #5: ff110001d6026a40
(&q->q_usage_counter(queue)#6){+.+.}-{0:0}, at:
blk_mq_freeze_queue_nomemsave+0x12/0x20
[ 1727.485665] #6: ff110001d6026f98 (&q->elevator_lock){+.+.}-{4:4},
at: elevator_change+0x12d/0x500
[ 1727.495681]
[ 1727.495681] stack backtrace:
[ 1727.500547] CPU: 3 UID: 0 PID: 1709 Comm: bash Kdump: loaded
Tainted: G S 6.16.0+ #1 PREEMPT(voluntary)
[ 1727.500554] Tainted: [S]=CPU_OUT_OF_SPEC
[ 1727.500557] Hardware name: Lenovo ThinkSystem SR650 V2/7Z73CTO1WW,
BIOS AFE120G-1.40 09/20/2022
[ 1727.500559] Call Trace:
[ 1727.500562] <TASK>
[ 1727.500565] dump_stack_lvl+0x6f/0xb0
[ 1727.500573] print_circular_bug.cold+0x38/0x45
[ 1727.500580] check_noncircular+0x148/0x160
[ 1727.500584] ? __lock_release.isra.0+0x1a4/0x2c0
[ 1727.500592] check_prev_add+0xf1/0xcd0
[ 1727.500595] ? alloc_chain_hlocks+0x8/0x1d0
[ 1727.500601] ? add_chain_cache+0x12c/0x310
[ 1727.500608] validate_chain+0x487/0x570
[ 1727.500611] ? lock_acquire.part.0+0xbd/0x260
[ 1727.500617] __lock_acquire+0x57c/0xbd0
[ 1727.500622] lock_acquire.part.0+0xbd/0x260
[ 1727.500626] ? pcpu_alloc_noprof+0x8a3/0xd50
[ 1727.500633] ? rcu_is_watching+0x15/0xb0
[ 1727.500639] ? lock_acquire+0x10b/0x150
[ 1727.500645] __mutex_lock+0x1a9/0x1b20
[ 1727.500650] ? pcpu_alloc_noprof+0x8a3/0xd50
[ 1727.500655] ? pcpu_alloc_noprof+0x8a3/0xd50
[ 1727.500659] ? elv_iosched_store+0x27b/0x2f0
[ 1727.500663] ? queue_attr_store+0x22f/0x2f0
[ 1727.500668] ? kernfs_fop_write_iter+0x3a0/0x5a0
[ 1727.500673] ? vfs_write+0x525/0xfd0
[ 1727.500678] ? ksys_write+0xf9/0x1d0
[ 1727.500681] ? do_syscall_64+0x94/0x8d0
[ 1727.500685] ? entry_SYSCALL_64_after_hwframe+0x76/0x7e
[ 1727.500689] ? __pfx___mutex_lock+0x10/0x10
[ 1727.500702] ? pcpu_alloc_noprof+0x8a3/0xd50
[ 1727.500707] pcpu_alloc_noprof+0x8a3/0xd50
[ 1727.500715] ? kasan_save_track+0x14/0x30
[ 1727.500720] kyber_queue_data_alloc+0x16d/0x610
[ 1727.500724] ? debug_mutex_init+0x37/0x70
[ 1727.500731] kyber_init_sched+0x18/0xa0
[ 1727.500735] blk_mq_init_sched+0x26e/0x4e0
[ 1727.500741] ? __pfx_blk_mq_exit_sched+0x10/0x10
[ 1727.500746] ? __pfx_blk_mq_init_sched+0x10/0x10
[ 1727.500754] elevator_switch+0x1ae/0x650
[ 1727.500759] elevator_change+0x2db/0x500
[ 1727.500766] elv_iosched_store+0x27b/0x2f0
[ 1727.500771] ? __pfx_elv_iosched_store+0x10/0x10
[ 1727.500777] ? kernfs_fop_write_iter+0x260/0x5a0
[ 1727.500782] ? kernfs_fop_write_iter+0x260/0x5a0
[ 1727.500789] ? rcu_is_watching+0x15/0xb0
[ 1727.500795] ? __pfx_sysfs_kf_write+0x10/0x10
[ 1727.500799] queue_attr_store+0x22f/0x2f0
[ 1727.500805] ? __pfx_queue_attr_store+0x10/0x10
[ 1727.500811] ? __lock_acquire+0x57c/0xbd0
[ 1727.500817] ? find_held_lock+0x32/0x90
[ 1727.500822] ? local_clock_noinstr+0xd/0xe0
[ 1727.500827] ? __lock_release.isra.0+0x1a4/0x2c0
[ 1727.500833] ? sysfs_file_kobj+0xb3/0x1c0
[ 1727.500837] ? sysfs_file_kobj+0xbd/0x1c0
[ 1727.500842] ? __pfx_sysfs_kf_write+0x10/0x10
[ 1727.500846] kernfs_fop_write_iter+0x3a0/0x5a0
[ 1727.500853] vfs_write+0x525/0xfd0
[ 1727.500860] ? __pfx_vfs_write+0x10/0x10
[ 1727.500869] ? local_clock_noinstr+0xd/0xe0
[ 1727.500874] ? __lock_release.isra.0+0x1a4/0x2c0
[ 1727.500879] ksys_write+0xf9/0x1d0
[ 1727.500883] ? __pfx_ksys_write+0x10/0x10
[ 1727.500887] ? entry_SYSCALL_64_after_hwframe+0x76/0x7e
[ 1727.500893] do_syscall_64+0x94/0x8d0
[ 1727.500906] ? fput_close+0x156/0x1c0
[ 1727.500912] ? __pfx_fput_close+0x10/0x10
[ 1727.500919] ? filp_close+0x1d/0x30
[ 1727.500923] ? do_dup2+0x296/0x500
[ 1727.500927] ? lockdep_hardirqs_on+0x78/0x100
[ 1727.500934] ? entry_SYSCALL_64_after_hwframe+0x76/0x7e
[ 1727.500938] ? lockdep_hardirqs_on+0x78/0x100
[ 1727.500942] ? do_syscall_64+0x139/0x8d0
[ 1727.500947] ? entry_SYSCALL_64_after_hwframe+0x76/0x7e
[ 1727.500951] ? lockdep_hardirqs_on+0x78/0x100
[ 1727.500955] ? do_syscall_64+0x139/0x8d0
[ 1727.500959] ? entry_SYSCALL_64_after_hwframe+0x76/0x7e
[ 1727.500962] ? lockdep_hardirqs_on+0x78/0x100
[ 1727.500967] ? do_syscall_64+0x139/0x8d0
[ 1727.500972] ? exc_page_fault+0x78/0xf0
[ 1727.500978] ? rcu_is_watching+0x15/0xb0
[ 1727.500983] ? clear_bhb_loop+0x50/0xa0
[ 1727.500989] entry_SYSCALL_64_after_hwframe+0x76/0x7e
[ 1727.500992] RIP: 0033:0x7f10fec4e894
[ 1727.500997] Code: c7 00 16 00 00 00 b8 ff ff ff ff c3 66 2e 0f 1f
84 00 00 00 00 00 f3 0f 1e fa 80 3d 35 d8 0d 00 00 74 13 b8 01 00 00
00 0f 05 <48> 3d 00 f0 ff ff 77 54 c3 0f 1f 00 48 83 ec 28 48 89 54 24
18 48
[ 1727.501001] RSP: 002b:00007ffcb8b9d868 EFLAGS: 00000202 ORIG_RAX:
0000000000000001
[ 1727.501007] RAX: ffffffffffffffda RBX: 0000000000000006 RCX: 00007f10fec4e894
[ 1727.501010] RDX: 0000000000000006 RSI: 000055ecf55e8f40 RDI: 0000000000000001
[ 1727.501013] RBP: 000055ecf55e8f40 R08: 0000000000000073 R09: 00000000ffffffff
[ 1727.501016] R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000006
[ 1727.501018] R13: 00007f10fed255c0 R14: 0000000000000006 R15: 00007f10fed22f00
[ 1727.501027] </TASK>
On Fri, Aug 8, 2025 at 1:23 PM Changhui Zhong <czhong@xxxxxxxxxx> wrote:
>
> Hello,
>
> the following warning was triggered by 'blktests block/020' tests on
> aarch64 platform,
> please help check and let me know if you need any info/test, thanks.
>
> repo：https://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux-block.git
> branch：for-next
> INFO: HEAD of cloned kernel：
> commit 20c74c07321713217b2f84c55dfd717729aa6111
> Merge: f1815afd0877 407728da41cd
> Author: Jens Axboe <axboe@xxxxxxxxx>
> Date: Mon Aug 4 09:23:02 2025 -0600
>
> Merge branch 'block-6.17' into for-next
>
> * block-6.17:
> block, bfq: Reorder struct bfq_iocq_bfqq_data
>
> dmesg log：
>
> [ 670.939355] run blktests block/020 at 2025-08-07 07:10:45
> [ 673.008290] restraintd[3128]: *** Current Time: Thu Aug 07 07:10:47
> 2025 Localwatchdog at: Thu Aug 07 12:00:47 2025
> [ 695.875845]
> [ 695.877344] ======================================================
> [ 695.883515] WARNING: possible circular locking dependency detected
> [ 695.889684] 6.16.0+ #1 Not tainted
> [ 695.893075] ------------------------------------------------------
> [ 695.899243] check/12334 is trying to acquire lock:
> [ 695.904022] ffffa1f3ed4291f0 (pcpu_alloc_mutex){+.+.}-{4:4}, at:
> pcpu_alloc_noprof+0x128/0xeb8
> [ 695.912635]
> [ 695.912635] but task is already holding lock:
> [ 695.918455] ffff0800bee44578 (&q->elevator_lock){+.+.}-{4:4}, at:
> elevator_change+0x138/0x440
> [ 695.926975]
> [ 695.926975] which lock already depends on the new lock.
> [ 695.926975]
> [ 695.935139]
> [ 695.935139] the existing dependency chain (in reverse order) is:
> [ 695.942608]
> [ 695.942608] -> #3 (&q->elevator_lock){+.+.}-{4:4}:
> [ 695.948868] __lock_acquire+0x4bc/0x990
> [ 695.953216] lock_acquire.part.0+0x174/0x2a8
> [ 695.957997] lock_acquire+0xa0/0x1b8
> [ 695.962083] __mutex_lock+0x158/0x1090
> [ 695.966343] mutex_lock_nested+0x2c/0x40
> [ 695.970775] elevator_change+0x138/0x440
> [ 695.975208] elv_iosched_store+0x214/0x2c0
> [ 695.979814] queue_attr_store+0x200/0x270
> [ 695.984335] sysfs_kf_write+0xcc/0x120
> [ 695.988595] kernfs_fop_write_iter+0x288/0x430
> [ 695.993549] new_sync_write+0x214/0x4d0
> [ 695.997895] vfs_write+0x440/0x5b0
> [ 696.001806] ksys_write+0xf8/0x1f0
> [ 696.005718] __arm64_sys_write+0x74/0xb0
> [ 696.010151] invoke_syscall.constprop.0+0xdc/0x1e8
> [ 696.015454] do_el0_svc+0x154/0x1d0
> [ 696.019453] el0_svc+0x54/0x180
> [ 696.023105] el0t_64_sync_handler+0xa0/0xe8
> [ 696.027799] el0t_64_sync+0x1ac/0x1b0
> [ 696.031971]
> [ 696.031971] -> #2 (&q->q_usage_counter(io)#6){++++}-{0:0}:
> [ 696.038926] __lock_acquire+0x4bc/0x990
> [ 696.043272] lock_acquire.part.0+0x174/0x2a8
> [ 696.048052] lock_acquire+0xa0/0x1b8
> [ 696.052138] blk_alloc_queue+0x4e8/0x608
> [ 696.056571] blk_mq_alloc_queue+0x150/0x240
> [ 696.061265] __blk_mq_alloc_disk+0x28/0x1d8
> [ 696.065958] null_add_dev+0x680/0x1188 [null_blk]
> [ 696.071183] nullb_device_power_store+0x1f4/0x340 [null_blk]
> [ 696.077357] configfs_write_iter+0x24c/0x378
> [ 696.082138] new_sync_write+0x214/0x4d0
> [ 696.086484] vfs_write+0x440/0x5b0
> [ 696.090395] ksys_write+0xf8/0x1f0
> [ 696.094306] __arm64_sys_write+0x74/0xb0
> [ 696.098739] invoke_syscall.constprop.0+0xdc/0x1e8
> [ 696.104040] do_el0_svc+0x154/0x1d0
> [ 696.108039] el0_svc+0x54/0x180
> [ 696.111690] el0t_64_sync_handler+0xa0/0xe8
> [ 696.116383] el0t_64_sync+0x1ac/0x1b0
> [ 696.120555]
> [ 696.120555] -> #1 (fs_reclaim){+.+.}-{0:0}:
> [ 696.126206] __lock_acquire+0x4bc/0x990
> [ 696.130553] lock_acquire.part.0+0x174/0x2a8
> [ 696.135333] lock_acquire+0xa0/0x1b8
> [ 696.139420] fs_reclaim_acquire+0x140/0x170
> [ 696.144114] __alloc_frozen_pages_noprof+0x17c/0x4f0
> [ 696.149588] __alloc_pages_noprof+0x1c/0xb0
> [ 696.154281] pcpu_alloc_pages.isra.0+0x12c/0x448
> [ 696.159409] pcpu_populate_chunk+0x4c/0x98
> [ 696.164016] pcpu_alloc_noprof+0x3b0/0xeb8
> [ 696.168624] iommu_dma_init_fq+0x148/0x690
> [ 696.173231] iommu_dma_init_domain+0x488/0x6a0
> [ 696.178185] iommu_setup_dma_ops+0x138/0x210
> [ 696.182965] bus_iommu_probe+0x1b0/0x3e8
> [ 696.187398] iommu_device_register+0x15c/0x240
> [ 696.192351] arm_smmu_device_probe+0xbe8/0x1260
> [ 696.197393] platform_probe+0xcc/0x198
> [ 696.201654] really_probe+0x188/0x800
> [ 696.205826] __driver_probe_device+0x164/0x360
> [ 696.210779] driver_probe_device+0x64/0x1a8
> [ 696.215472] __driver_attach+0x180/0x490
> [ 696.219904] bus_for_each_dev+0x104/0x1a0
> [ 696.224424] driver_attach+0x44/0x68
> [ 696.228509] bus_add_driver+0x23c/0x4e8
> [ 696.232855] driver_register+0x15c/0x3a8
> [ 696.237287] __platform_driver_register+0x64/0x98
> [ 696.242502] arm_smmu_driver_init+0x28/0x40
> [ 696.247197] do_one_initcall+0xd4/0x370
> [ 696.251544] do_initcalls+0x1b0/0x200
> [ 696.255716] kernel_init_freeable+0x280/0x2c0
> [ 696.260582] kernel_init+0x28/0x160
> [ 696.264581] ret_from_fork+0x10/0x20
> [ 696.268668]
> [ 696.268668] -> #0 (pcpu_alloc_mutex){+.+.}-{4:4}:
> [ 696.274840] check_prev_add+0xec/0x658
> [ 696.279100] validate_chain+0x2dc/0x340
> [ 696.283446] __lock_acquire+0x4bc/0x990
> [ 696.287792] lock_acquire.part.0+0x174/0x2a8
> [ 696.292572] lock_acquire+0xa0/0x1b8
> [ 696.296658] __mutex_lock+0x158/0x1090
> [ 696.300917] _mutex_lock_killable+0x2c/0x40
> [ 696.305610] pcpu_alloc_noprof+0x128/0xeb8
> [ 696.310217] kyber_queue_data_alloc+0x150/0x580
> [ 696.315258] kyber_init_sched+0x28/0xb0
> [ 696.319605] blk_mq_init_sched+0x1f0/0x410
> [ 696.324213] elevator_switch+0x184/0x5a0
> [ 696.328645] elevator_change+0x29c/0x440
> [ 696.333077] elv_iosched_store+0x214/0x2c0
> [ 696.337684] queue_attr_store+0x200/0x270
> [ 696.342204] sysfs_kf_write+0xcc/0x120
> [ 696.346463] kernfs_fop_write_iter+0x288/0x430
> [ 696.351416] new_sync_write+0x214/0x4d0
> [ 696.355761] vfs_write+0x440/0x5b0
> [ 696.359672] ksys_write+0xf8/0x1f0
> [ 696.363585] __arm64_sys_write+0x74/0xb0
> [ 696.368017] invoke_syscall.constprop.0+0xdc/0x1e8
> [ 696.373318] do_el0_svc+0x154/0x1d0
> [ 696.377317] el0_svc+0x54/0x180
> [ 696.380969] el0t_64_sync_handler+0xa0/0xe8
> [ 696.385663] el0t_64_sync+0x1ac/0x1b0
> [ 696.389835]
> [ 696.389835] other info that might help us debug this:
> [ 696.389835]
> [ 696.397826] Chain exists of:
> [ 696.397826] pcpu_alloc_mutex --> &q->q_usage_counter(io)#6 -->
> &q->elevator_lock
> [ 696.397826]
> [ 696.409731] Possible unsafe locking scenario:
> [ 696.409731]
> [ 696.415638] CPU0 CPU1
> [ 696.420155] ---- ----
> [ 696.424673] lock(&q->elevator_lock);
> [ 696.428412] lock(&q->q_usage_counter(io)#6);
> [ 696.435364] lock(&q->elevator_lock);
> [ 696.441620] lock(pcpu_alloc_mutex);
> [ 696.445272]
> [ 696.445272] *** DEADLOCK ***
> [ 696.445272]
> [ 696.451179] 7 locks held by check/12334:
> [ 696.455091] #0: ffff07ffed062448 (sb_writers#4){.+.+}-{0:0}, at:
> vfs_write+0x404/0x5b0
> [ 696.463090] #1: ffff0800a7d3e890 (&of->mutex#2){+.+.}-{4:4}, at:
> kernfs_fop_write_iter+0x1fc/0x430
> [ 696.472131] #2: ffff07ff9128eba0 (kn->active#107){.+.+}-{0:0}, at:
> kernfs_fop_write_iter+0x218/0x430
> [ 696.481345] #3: ffff0800c80841d8
> (&set->update_nr_hwq_lock){++++}-{4:4}, at:
> elv_iosched_store+0x18c/0x2c0
> [ 696.491080] #4: ffff0800bee43fe0
> (&q->q_usage_counter(io)#6){++++}-{0:0}, at:
> blk_mq_freeze_queue_nomemsave+0x20/0x40
> [ 696.501770] #5: ffff0800bee44020
> (&q->q_usage_counter(queue)#2){+.+.}-{0:0}, at:
> blk_mq_freeze_queue_nomemsave+0x20/0x40
> [ 696.512720] #6: ffff0800bee44578 (&q->elevator_lock){+.+.}-{4:4},
> at: elevator_change+0x138/0x440
> [ 696.521674]
> [ 696.521674] stack backtrace:
> [ 696.526020] CPU: 42 UID: 0 PID: 12334 Comm: check Kdump: loaded Not
> tainted 6.16.0+ #1 PREEMPT(voluntary)
> [ 696.535663] Hardware name: GIGABYTE R152-P31-00/MP32-AR1-00, BIOS
> F31n (SCP: 2.10.20220810) 09/30/2022
> [ 696.544956] Call trace:
> [ 696.547392] show_stack+0x34/0x98 (C)
> [ 696.551046] dump_stack_lvl+0xa8/0xe8
> [ 696.554698] dump_stack+0x1c/0x38
> [ 696.558003] print_circular_bug+0xf0/0x100
> [ 696.562089] check_noncircular+0x174/0x188
> [ 696.566175] check_prev_add+0xec/0x658
> [ 696.569915] validate_chain+0x2dc/0x340
> [ 696.573741] __lock_acquire+0x4bc/0x990
> [ 696.577566] lock_acquire.part.0+0x174/0x2a8
> [ 696.581826] lock_acquire+0xa0/0x1b8
> [ 696.585392] __mutex_lock+0x158/0x1090
> [ 696.589130] _mutex_lock_killable+0x2c/0x40
> [ 696.593303] pcpu_alloc_noprof+0x128/0xeb8
> [ 696.597390] kyber_queue_data_alloc+0x150/0x580
> [ 696.601911] kyber_init_sched+0x28/0xb0
> [ 696.605737] blk_mq_init_sched+0x1f0/0x410
> [ 696.609823] elevator_switch+0x184/0x5a0
> [ 696.613736] elevator_change+0x29c/0x440
> [ 696.617648] elv_iosched_store+0x214/0x2c0
> [ 696.621734] queue_attr_store+0x200/0x270
> [ 696.625733] sysfs_kf_write+0xcc/0x120
> [ 696.629472] kernfs_fop_write_iter+0x288/0x430
> [ 696.633904] new_sync_write+0x214/0x4d0
> [ 696.637729] vfs_write+0x440/0x5b0
> [ 696.641120] ksys_write+0xf8/0x1f0
> [ 696.644511] __arm64_sys_write+0x74/0xb0
> [ 696.648423] invoke_syscall.constprop.0+0xdc/0x1e8
> [ 696.653204] do_el0_svc+0x154/0x1d0
> [ 696.656683] el0_svc+0x54/0x180
> [ 696.659813] el0t_64_sync_handler+0xa0/0xe8
> [ 696.663986] el0t_64_sync+0x1ac/0x1b0
> [ 728.598328] null_blk: disk nullb0 created
> [ 728.598344] null_blk: module loaded
>
> Best Regards,
> Changhui
