INFO: task syz.0.6146:21089 blocked for more than 143 seconds.
      Tainted: G             L      syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.6146      state:D stack:28808 pid:21089 tgid:21087 ppid:18321  task_flags:0x400040 flags:0x00080002
Call Trace:
 <TASK>
 __schedule+0x17d9/0x56c0
 schedule+0x164/0x2b0
 cgroup_lock_and_drain_offline+0x51a/0x650
 cgroup_kn_lock_live+0x120/0x230
 cgroup_subtree_control_write+0x4b5/0x1080
 cgroup_file_write+0x331/0x8f0
 kernfs_fop_write_iter+0x3a4/0x540
 vfs_write+0x612/0xba0
 ksys_write+0x150/0x270
 do_syscall_64+0x174/0x580
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f067939e159
RSP: 002b:00007f067a1d2028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f0679626090 RCX: 00007f067939e159
RDX: 0000000000000005 RSI: 00002000000001c0 RDI: 0000000000000005
RBP: 00007f067943506b R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f0679626128 R14: 00007f0679626090 R15: 00007ffd14b4a4f8
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/35:
 #0: 
ffffffff8eb59c60 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180
2 locks held by kworker/u10:1/37:
 #0: ffff88823c63b160 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2d/0x160
 #1: ffff88823c624440 (psi_seq){-.-.}-{0:0}, at: psi_task_switch+0x57/0x7d0
2 locks held by getty/5428:
 #0: 
ffff88816ad760a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70
 #1: ffffc900034732e8 (
&ldata->atomic_read_lock
){+.+.}-{4:4}, at: n_tty_read+0x45a/0x1360
2 locks held by syz.2.4544/16853:
3 locks held by syz.8.4816/17634:
3 locks held by syz.0.6146/21089:
 #0: 
ffff88811409e2f0 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x246/0x320
 #1: 
ffff88810c3dc450 (sb_writers#9){.+.+}-{0:0}, at: vfs_write+0x22b/0xba0
 #2: 
ffff888103f96080 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1d8/0x540
3 locks held by syz.6.6383/21971:
 #0: 
ffff88816f8594f0 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x246/0x320
 #1: ffff88810c3dc450
 (
sb_writers#9){.+.+}-{0:0}, at: vfs_write+0x22b/0xba0
 #2: ffff88819f0d4080 (
&of->mutex
){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1d8/0x540

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

NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 35 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/0x380
 sys_info+0x135/0x170
 watchdog+0xfd7/0x1030
 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: 17634 Comm: syz.8.4816 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:vprintk_emit+0x45d/0x560
Code: 0f 84 44 ff ff ff e8 f2 69 21 00 fb eb 44 e8 ea 69 21 00 e8 85 fd 29 0a 4d 85 f6 74 94 e8 db 69 21 00 fb 48 c7 c7 a0 bf b4 8e <31> f6 ba 01 00 00 00 31 c9 41 b8 01 00 00 00 45 31 c9 53 e8 fb 1b
RSP: 0018:ffffc90007687440 EFLAGS: 00000246
RAX: ffffffff81a587a5 RBX: ffffffff81a5861f RCX: 0000000000080000
RDX: ffffc900239aa000 RSI: 000000000007ffff RDI: ffffffff8eb4bfa0
RBP: ffffc900076874f0 R08: ffffffff90575937 R09: 1ffffffff20aeb26
R10: dffffc0000000000 R11: fffffbfff20aeb27 R12: 0000000000000000
R13: 000000000000002a R14: 0000000000000200 R15: 1ffff92000ed0e8c
FS:  00007f349e0056c0(0000) GS:ffff8882a8f59000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f918afef2f8 CR3: 000000019f6b2000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 _printk+0xdd/0x130
 __nilfs_msg+0x373/0x450
 nilfs_clean_segments+0x6f2/0xbb0
 nilfs_ioctl+0x2619/0x2780
 __se_sys_ioctl+0xfc/0x170
 do_syscall_64+0x174/0x580
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f349d19e159
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:00007f349e005028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f349d425fa0 RCX: 00007f349d19e159
RDX: 0000200000000040 RSI: 0000000040786e88 RDI: 0000000000000004
RBP: 00007f349d23506b R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f349d426038 R14: 00007f349d425fa0 R15: 00007ffebf86b118
 </TASK>
