[bug report] WARNING: block/blk-mq-debugfs.c:620 at debugfs_create_files.isra.0+0x54/0x60, CPU#220: kworker/u1036:7/70421
Yu Kuai
yukuai at fnnas.com
Sun Feb 8 21:41:41 PST 2026
Hi,
在 2026/2/6 15:25, Shinichiro Kawasaki 写道:
> On Feb 03, 2026 / 20:28, Yi Zhang wrote:
>> Hello
>>
>> CKI reported the following failure today. Seems it was introduced from
>> the recently blk-mq-debugfs update, please help check and let me know
>> if you need any testing/info.
>>
>> Reproducer: blktests nvme/tcp nvme/005
>> Commit message: Merge branch 'for-7.0/block' into for-next
>>
>> dmesg:
>> [ 951.319384] run blktests nvme/005 at 2026-02-02 17:59:35
>> [ 951.346116] loop0: detected capacity change from 0 to 2097152
>> [ 951.356428] nvmet: adding nsid 1 to subsystem blktests-subsystem-1
>> [ 951.370823] nvmet_tcp: enabling port 0 (127.0.0.1:4420)
>> [ 951.397438] nvmet: Created nvm controller 1 for subsystem
>> blktests-subsystem-1 for NQN
>> nqn.2014-08.org.nvmexpress:uuid:0f01fb42-9f7f-4856-b0b3-51e60b8de349.
>> [ 951.412081] nvme nvme0: creating 128 I/O queues.
>> [ 951.425914] nvme nvme0: mapped 128/0/0 default/read/poll queues.
>> [ 951.467027] nvme nvme0: new ctrl: NQN "blktests-subsystem-1", addr
>> 127.0.0.1:4420, hostnqn:
>> nqn.2014-08.org.nvmexpress:uuid:0f01fb42-9f7f-4856-b0b3-51e60b8de349
>> [ 951.784608] nvmet: Created nvm controller 2 for subsystem
>> blktests-subsystem-1 for NQN
>> nqn.2014-08.org.nvmexpress:uuid:0f01fb42-9f7f-4856-b0b3-51e60b8de349.
>> [ 951.798920] nvme nvme0: creating 128 I/O queues.
>> [ 951.871600] nvme nvme0: mapped 128/0/0 default/read/poll queues.
>> [ 951.880680] ------------[ cut here ]------------
>> [ 951.885309] WARNING: block/blk-mq-debugfs.c:620 at
>> debugfs_create_files.isra.0+0x54/0x60, CPU#220: kworker/u1036:7/70421
> FYI, I also observe this WARN at debugfs_create_files() using the blktests test
> case zbd/012. When I repeat zbd/012 several times on the kernel with the tag
> next-20260204, the WARN below is reported:
Thanks for the test, although queue is unfrozen before debugfs_create_files() from
switching elevator, however, it's still possible queue can be frozen from other
context concurrently.
This warning is not false positive, however, we'll have to fix nvme cases first
before we can fix this.
>
> [ 1304.543824] [ T12755] ------------[ cut here ]------------
> [ 1304.545792] [ T12755] WARNING: block/blk-mq-debugfs.c:620 at debugfs_create_files+0x247/0x2c0, CPU#2: check/12755
> [ 1304.547377] [ T12755] Modules linked in: scsi_debug null_blk 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_nat nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 nf_tables qrtr sunrpc 9pnet_virtio 9pnet pcspkr netfs i2c_piix4 i2c_smbus loop fuse dm_multipath nfnetlink vsock_loopback vmw_vsock_virtio_transport_common zram vsock xfs bochs drm_client_lib drm_shmem_helper drm_kms_helper nvme drm nvme_core floppy sym53c8xx nvme_keyring e1000 scsi_transport_spi nvme_auth hkdf serio_raw ata_generic pata_acpi i2c_dev qemu_fw_cfg [last unloaded: scsi_debug]
> [ 1304.554851] [ T12755] CPU: 2 UID: 0 PID: 12755 Comm: check Not tainted 6.19.0-rc8-next-20260204 #383 PREEMPT(full)
> [ 1304.556421] [ T12755] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-4.fc42 04/01/2014
> [ 1304.557886] [ T12755] RIP: 0010:debugfs_create_files+0x247/0x2c0
> [ 1304.559074] [ T12755] Code: ff e8 1d b0 83 01 83 f8 01 0f 85 67 fe ff ff 0f 0b e9 60 fe ff ff 0f 0b e9 59 fe ff ff 48 89 ef e8 2e 59 69 ff e9 07 fe ff ff <0f> 0b e9 6e ff ff ff e8 fd 58 69 ff e9 9a fe ff ff 48 89 df e8 30
> [ 1304.562112] [ T12755] RSP: 0018:ffff888147b77530 EFLAGS: 00010202
> [ 1304.563343] [ T12755] RAX: 0000000000000000 RBX: ffffffffaa567360 RCX: 0000000000000001
> [ 1304.564728] [ T12755] RDX: 0000000000000001 RSI: ffffffffaae6910d RDI: ffff888130361a48
> [ 1304.566104] [ T12755] RBP: ffffffffabe49734 R08: 0000000000000001 R09: ffffed1022804075
> [ 1304.567487] [ T12755] R10: 0000000000000002 R11: ffff88812610c390 R12: ffff8881140202f0
> [ 1304.568850] [ T12755] R13: ffff888130361310 R14: ffff888130361310 R15: ffffffffaa567af0
> [ 1304.570246] [ T12755] FS: 00007f40d67a1740(0000) GS:ffff8884011ea000(0000) knlGS:0000000000000000
> [ 1304.571721] [ T12755] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> [ 1304.573019] [ T12755] CR2: 000000001e02a810 CR3: 00000001148f6000 CR4: 00000000000006f0
> [ 1304.574409] [ T12755] Call Trace:
> [ 1304.575361] [ T12755] <TASK>
> [ 1304.576229] [ T12755] blk_mq_sched_reg_debugfs+0x28/0xe0
> [ 1304.577287] [ T12755] elevator_change_done+0x2f2/0x610
> [ 1304.578342] [ T12755] ? lockdep_hardirqs_on_prepare+0x50/0x1b0
> [ 1304.579452] [ T12755] ? __pfx_elevator_change_done+0x10/0x10
> [ 1304.580469] [ T12755] ? find_held_lock+0x2b/0x80
> [ 1304.581346] [ T12755] ? elevator_change+0x2ed/0x4f0
> [ 1304.582246] [ T12755] ? lock_release+0x1a7/0x320
> [ 1304.583142] [ T12755] ? __pfx_sysfs_kf_write+0x10/0x10
> [ 1304.584087] [ T12755] elevator_change+0x283/0x4f0
> [ 1304.584970] [ T12755] ? __pfx_sysfs_kf_write+0x10/0x10
> [ 1304.585887] [ T12755] elv_iosched_store+0x31d/0x3a0
> [ 1304.586784] [ T12755] ? __pfx_elv_iosched_store+0x10/0x10
> [ 1304.587724] [ T12755] ? lock_acquire+0x1b0/0x340
> [ 1304.588597] [ T12755] ? kernfs_fop_write_iter+0x257/0x5e0
> [ 1304.589523] [ T12755] ? __pfx___might_resched+0x10/0x10
> [ 1304.590396] [ T12755] ? __might_fault+0x97/0x140
> [ 1304.591265] [ T12755] ? __pfx_sysfs_kf_write+0x10/0x10
> [ 1304.592185] [ T12755] queue_attr_store+0x235/0x360
> [ 1304.593064] [ T12755] ? __lock_acquire+0x497/0x2230
> [ 1304.593929] [ T12755] ? __pfx_queue_attr_store+0x10/0x10
> [ 1304.594787] [ T12755] ? lock_acquire+0x1b0/0x340
> [ 1304.595629] [ T12755] ? sysfs_file_kobj+0x1d/0x1b0
> [ 1304.596473] [ T12755] ? lock_acquire+0x1c0/0x340
> [ 1304.597261] [ T12755] ? find_held_lock+0x2b/0x80
> [ 1304.598107] [ T12755] ? sysfs_file_kobj+0xaf/0x1b0
> [ 1304.598937] [ T12755] ? lock_release+0x1a7/0x320
> [ 1304.599766] [ T12755] ? sysfs_file_kobj+0xb9/0x1b0
> [ 1304.600598] [ T12755] ? sysfs_kf_write+0x61/0x160
> [ 1304.601378] [ T12755] ? __pfx_sysfs_kf_write+0x10/0x10
> [ 1304.602276] [ T12755] kernfs_fop_write_iter+0x3d6/0x5e0
> [ 1304.603148] [ T12755] ? __pfx_kernfs_fop_write_iter+0x10/0x10
> [ 1304.604048] [ T12755] vfs_write+0x523/0xf80
> [ 1304.604784] [ T12755] ? arch_stack_walk+0xb3/0x100
> [ 1304.605573] [ T12755] ? __pfx_vfs_write+0x10/0x10
> [ 1304.606283] [ T12755] ? lock_acquire+0x1b0/0x340
> [ 1304.607038] [ T12755] ? get_close_on_exec+0x1f/0x230
> [ 1304.607774] [ T12755] ? get_close_on_exec+0xfc/0x230
> [ 1304.608502] [ T12755] ? lock_release+0x1a7/0x320
> [ 1304.609150] [ T12755] ksys_write+0xfb/0x200
> [ 1304.609803] [ T12755] ? __pfx_ksys_write+0x10/0x10
> [ 1304.610495] [ T12755] ? lock_release+0x1a7/0x320
> [ 1304.611181] [ T12755] do_syscall_64+0x136/0x1540
> [ 1304.611845] [ T12755] ? do_wp_page+0x168d/0x3610
> [ 1304.612505] [ T12755] ? lock_acquire+0x1b0/0x340
> [ 1304.613151] [ T12755] ? __pfx_do_wp_page+0x10/0x10
> [ 1304.613803] [ T12755] ? lock_acquire+0x1b0/0x340
> [ 1304.614439] [ T12755] ? do_raw_spin_lock+0x124/0x260
> [ 1304.615078] [ T12755] ? lock_acquire+0x1c0/0x340
> [ 1304.615697] [ T12755] ? __pfx_do_raw_spin_lock+0x10/0x10
> [ 1304.616369] [ T12755] ? __pfx_pte_write+0x10/0x10
> [ 1304.617022] [ T12755] ? __handle_mm_fault+0x12b2/0x1d50
> [ 1304.617677] [ T12755] ? __lock_acquire+0x497/0x2230
> [ 1304.618336] [ T12755] ? __pfx_css_rstat_updated+0x10/0x10
> [ 1304.619065] [ T12755] ? lock_acquire+0x1b0/0x340
> [ 1304.619677] [ T12755] ? count_memcg_events_mm.constprop.0+0x22/0x130
> [ 1304.620438] [ T12755] ? rcu_is_watching+0x11/0xb0
> [ 1304.621074] [ T12755] ? count_memcg_events+0x106/0x4a0
> [ 1304.621741] [ T12755] ? find_held_lock+0x2b/0x80
> [ 1304.622376] [ T12755] ? rcu_read_unlock+0x17/0x60
> [ 1304.623047] [ T12755] ? lock_release+0x1a7/0x320
> [ 1304.623656] [ T12755] ? find_held_lock+0x2b/0x80
> [ 1304.624290] [ T12755] ? exc_page_fault+0x83/0x110
> [ 1304.624926] [ T12755] ? lock_release+0x1a7/0x320
> [ 1304.625553] [ T12755] ? rcu_is_watching+0x11/0xb0
> [ 1304.626170] [ T12755] ? irqentry_exit+0xdd/0x6a0
> [ 1304.626793] [ T12755] ? lockdep_hardirqs_on_prepare+0xce/0x1b0
> [ 1304.627499] [ T12755] ? irqentry_exit+0xe2/0x6a0
> [ 1304.628114] [ T12755] entry_SYSCALL_64_after_hwframe+0x76/0x7e
> [ 1304.628821] [ T12755] RIP: 0033:0x7f40d681277e
> [ 1304.629425] [ T12755] Code: 4d 89 d8 e8 d4 bc 00 00 4c 8b 5d f8 41 8b 93 08 03 00 00 59 5e 48 83 f8 fc 74 11 c9 c3 0f 1f 80 00 00 00 00 48 8b 45 10 0f 05 <c9> c3 83 e2 39 83 fa 08 75 e7 e8 13 ff ff ff 0f 1f 00 f3 0f 1e fa
> [ 1304.631432] [ T12755] RSP: 002b:00007ffd15db4a60 EFLAGS: 00000202 ORIG_RAX: 0000000000000001
> [ 1304.632364] [ T12755] RAX: ffffffffffffffda RBX: 000000000000000c RCX: 00007f40d681277e
> [ 1304.633275] [ T12755] RDX: 000000000000000c RSI: 000000001e02a810 RDI: 0000000000000001
> [ 1304.634198] [ T12755] RBP: 00007ffd15db4a70 R08: 0000000000000000 R09: 0000000000000000
> [ 1304.635127] [ T12755] R10: 0000000000000000 R11: 0000000000000202 R12: 000000000000000c
> [ 1304.636044] [ T12755] R13: 000000001e02a810 R14: 00007f40d698d5c0 R15: 0000000000000000
> [ 1304.636962] [ T12755] </TASK>
> [ 1304.637532] [ T12755] irq event stamp: 6849
> [ 1304.638170] [ T12755] hardirqs last enabled at (6861): [<ffffffffa76e6bae>] __up_console_sem+0x5e/0x70
> [ 1304.639207] [ T12755] hardirqs last disabled at (6872): [<ffffffffa76e6b93>] __up_console_sem+0x43/0x70
> [ 1304.640247] [ T12755] softirqs last enabled at (5936): [<ffffffffa7521b66>] __irq_exit_rcu+0x126/0x240
> [ 1304.641299] [ T12755] softirqs last disabled at (5925): [<ffffffffa7521b66>] __irq_exit_rcu+0x126/0x240
> [ 1304.642338] [ T12755] ---[ end trace 0000000000000000 ]---
>
--
Thansk,
Kuai
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