INFO: task segctord:7867 blocked for more than 151 seconds.
      Tainted: G             L      syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:segctord        state:D stack:28680 pid:7867  tgid:7867  ppid:2      task_flags:0x200040 flags:0x00080000
Call Trace:
 <TASK>
 __schedule+0x1821/0x5740
 schedule+0x164/0x360
 schedule_preempt_disabled+0x13/0x30
 rwsem_down_write_slowpath+0x883/0x1080
 down_write+0x1bc/0x200
 nilfs_transaction_lock+0x252/0x4c0
 nilfs_segctor_thread+0x6b5/0xdc0
 kthread+0x388/0x470
 ret_from_fork+0x514/0xb70
 ret_from_fork_asm+0x1a/0x30
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/34:
 #0: 
ffffffff8e95cd60 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180
2 locks held by getty/5441:
 #0: 
ffff888172cc70a0
 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70
 #1: ffffc900034732e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45c/0x13a0
8 locks held by syz.4.441/7866:
1 lock held by segctord/7867:
 #0: ffff88802374a288 (&nilfs->ns_segctor_sem){++++}-{4:4}, at: nilfs_transaction_lock+0x252/0x4c0
5 locks held by kworker/1:7/8319:
 #0: ffff888105296940 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_scheduled_works+0xa35/0x1860
 #1: 
ffffc9000473fc40
 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_scheduled_works+0xa70/0x1860
 #2: ffff88810afaf1d8 (&dev->mutex){....}-{4:4}, at: hub_event+0x17f/0x4f30
 #3: ffff8881be9281d8 (&dev->mutex){....}-{4:4}, at: __device_attach+0x88/0x450
 #4: ffff888172a161a0 (&dev->mutex){....}-{4:4}, at: __device_attach+0x88/0x450

=============================================

NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 34 Comm: khungtaskd Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150
 nmi_cpu_backtrace+0x274/0x2d0
 nmi_trigger_cpumask_backtrace+0x17a/0x300
 sys_info+0x135/0x170
 watchdog+0xfd3/0x1030
 kthread+0x388/0x470
 ret_from_fork+0x514/0xb70
 ret_from_fork_asm+0x1a/0x30
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 7866 Comm: syz.4.441 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
RIP: 0010:arch_stack_walk+0x10f/0x150
Code: 78 ff ff ff 00 74 38 4c 8d bd 78 ff ff ff 4c 89 ff e8 95 65 09 00 48 85 c0 74 24 48 89 df 48 89 c6 4d 89 f3 2e e8 01 13 3e 0a <84> c0 74 11 4c 89 ff e8 c5 66 09 00 83 bd 78 ff ff ff 00 75 cf 65
RSP: 0018:ffffc90000a089c8 EFLAGS: 00000296
RAX: 0000000000000001 RBX: ffffc90000a08a80 RCX: 0000000000000100
RDX: dffffc0000000000 RSI: ffffffff83b1f8fb RDI: ffffc90000a08a80
RBP: ffffc90000a08a50 R08: ffffc90000a08a90 R09: 000000000000000f
R10: ffffc90000a08a18 R11: ffffffff81b0ebd0 R12: ffff88816cb10000
R13: ffff8881b944d800 R14: ffffffff81b0ebd0 R15: ffffc90000a089c8
FS:  00007f376a91b6c0(0000) GS:ffff8882a928d000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2e81fff8 CR3: 000000011554a000 CR4: 00000000000006f0
Call Trace:
 <IRQ>
 stack_trace_save+0xa9/0x100
 kasan_save_track+0x3e/0x80
 kasan_save_free_info+0x46/0x50
 __kasan_slab_free+0x5c/0x80
 slab_free_after_rcu_debug+0x12a/0x220
 rcu_core+0x7cd/0x1070
 handle_softirqs+0x22a/0x840
 __irq_exit_rcu+0xca/0x220
 irq_exit_rcu+0x9/0x30
 sysvec_apic_timer_interrupt+0xa6/0xc0
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20
RIP: 0010:vprintk_emit+0x45d/0x560
Code: 0f 84 44 ff ff ff e8 92 29 21 00 fb eb 44 e8 8a 29 21 00 e8 d5 1c 04 0a 4d 85 f6 74 94 e8 7b 29 21 00 fb 48 c7 c7 a0 f1 94 8e <31> f6 ba 01 00 00 00 31 c9 41 b8 01 00 00 00 45 31 c9 53 e8 cb 18
RSP: 0018:ffffc9000789ee20 EFLAGS: 00000293
RAX: ffffffff81a49855 RBX: ffffffff81a496cf RCX: ffff88816cb10000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff8e94f1a0
RBP: ffffc9000789eed0 R08: ffffffff9030b3f7 R09: 1ffffffff206167e
R10: dffffc0000000000 R11: fffffbfff206167f R12: 0000000000000000
R13: 0000000000000051 R14: 0000000000000200 R15: 1ffff92000f13dc8
 _printk+0xdd/0x130
 __nilfs_msg+0x373/0x450
 nilfs_sufile_updatev+0x21c/0x6d0
 nilfs_segctor_do_construct+0x1f55/0x76c0
 nilfs_segctor_construct+0x17b/0x690
 nilfs_clean_segments+0x3bd/0xa50
 nilfs_ioctl+0x261f/0x2780
 __se_sys_ioctl+0xfc/0x170
 do_syscall_64+0x15f/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f376999cdd9
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f376a91b028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f3769c16090 RCX: 00007f376999cdd9
RDX: 0000200000000640 RSI: 0000000040786e88 RDI: 000000000000000a
RBP: 00007f3769a32d69 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f3769c16128 R14: 00007f3769c16090 R15: 00007ffceed80a98
 </TASK>
