INFO: task syz.9.4284:16829 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.9.4284      state:D stack:27960 pid:16829 tgid:16828 ppid:11873  task_flags:0x400140 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: 0033:0x7f3288f9e0d9
RSP: 002b:00007f3289e80028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f3289225fa0 RCX: 00007f3288f9e0d9
RDX: 000000000000000c RSI: 00002000000001c0 RDI: 0000000000000005
RBP: 00007f3289035024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f3289226038 R14: 00007f3289225fa0 R15: 00007ffe7da348b8
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/35:
 #0: 
ffffffff8eb59c20
 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180
2 locks held by getty/5426:
 #0: ffff88816c4230a0 (&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
6 locks held by syz.0.174/6174:
3 locks held by syz.9.4284/16829:
 #0: ffff888169272ef0 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x246/0x320
 #1: ffff8881155d0450 (sb_writers#9){.+.+}-{0:0}, at: vfs_write+0x22b/0xba0
 #2: ffff888170a33c80 (&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: 6174 Comm: syz.0.174 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:lock_release+0x11c/0x3c0
Code: 8d 1c ad 00 00 00 00 4c 01 eb 48 8d 6c dd 00 48 89 ef 4c 89 f6 e8 14 cb 2c 0a 44 89 64 24 14 45 89 e5 85 c0 0f 84 d7 00 00 00 <48> 85 ed 0f 84 13 01 00 00 83 7d 24 00 0f 85 d6 01 00 00 8b 45 20
RSP: 0018:ffffc90000a08858 EFLAGS: 00000002
RAX: 0000000000000001 RBX: 0000000000000019 RCX: 0000000080000101
RDX: ffffffff90eeee01 RSI: ffffffff8eb59c20 RDI: ffff88816f4b8c68
RBP: ffff88816f4b8c68 R08: ffffc90000a08ff0 R09: 0000000000000000
R10: ffffc90000a089b8 R11: fffff52000141139 R12: 0000000000000005
R13: 0000000000000005 R14: ffffffff8eb59c20 R15: ffff88816f4b8000
FS:  00007f36d660d6c0(0000) GS:ffff8882a8f5d000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f62f7bef2f8 CR3: 0000000114c48000 CR4: 00000000000006f0
Call Trace:
 <IRQ>
 unwind_next_frame+0x1baa/0x2550
 arch_stack_walk+0x11b/0x150
 stack_trace_save+0xa9/0x100
 kasan_save_track+0x3e/0x80
 kasan_save_free_info+0x40/0x50
 __kasan_slab_free+0x5c/0x80
 kfree+0x1c5/0x640
 slab_free_after_rcu_debug+0x62/0x220
 rcu_core+0x78b/0x10a0
 handle_softirqs+0x225/0x840
 __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:__sanitizer_cov_trace_const_cmp4+0x4/0x90
Code: 74 11 18 48 89 44 11 20 e9 59 ac 0b 0a cc 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa <48> 8b 04 24 65 48 8b 15 d8 43 a5 11 65 8b 0d f9 43 a5 11 81 e1 00
RSP: 0018:ffffc9000784eb80 EFLAGS: 00000207
RAX: 00000000000002c8 RBX: ffffc9000784ec40 RCX: 0000000000000002
RDX: ffff88816f4b8000 RSI: 000000000000000c RDI: 0000000000000064
RBP: 00000000000002c8 R08: ffffc9000784ec57 R09: 0000000000000000
R10: ffffc9000784ec40 R11: fffff52000f09d8b R12: dffffc0000000000
R13: 00000000000002c8 R14: 0000000000000007 R15: 000000000000000c
 put_dec_trunc8+0x5a/0x340
 number+0x2d4/0xed0
 vsnprintf+0x91b/0xef0
 sprintf+0xe7/0x140
 info_print_prefix+0x16b/0x360
 record_print_text+0x181/0x4b0
 printk_get_next_message+0x297/0x880
 console_flush_all+0x4e3/0xaf0
 console_unlock+0xd1/0x1c0
 vprintk_emit+0x485/0x560
 _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: 0033:0x7f36d579e0d9
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:00007f36d660d028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f36d5a25fa0 RCX: 00007f36d579e0d9
RDX: 0000200000000040 RSI: 0000000040786e88 RDI: 0000000000000004
RBP: 00007f36d5835024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f36d5a26038 R14: 00007f36d5a25fa0 R15: 00007ffec5a0ee78
 </TASK>
