INFO: task syz.1.4292:21345 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.1.4292      state:D stack:28808 pid:21345 tgid:21337 ppid:5611   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: 0033:0x7f536d79ce59
RSP: 002b:00007f536e5bc028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f536da16180 RCX: 00007f536d79ce59
RDX: 000000000000000b RSI: 00002000000000c0 RDI: 000000000000000f
RBP: 00007f536d832e6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f536da16218 R14: 00007f536da16180 R15: 00007ffdca384218
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/35:
 #0: ffffffff8e959c20 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180
1 lock held by udevd/5059:
2 locks held by getty/5437:
 #0: ffff8881733130a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70
 #1: ffffc900034762e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45a/0x1360
2 locks held by kworker/u10:32/14764:
 #0: ffff888104374140 ((wq_completion)iou_exit){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0
 #1: ffffc90009b47c40 ((work_completion)(&ctx->exit_work)){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0
5 locks held by kworker/u10:37/14989:
3 locks held by syz.1.4292/21345:
 #0: ffff888191cc94f0 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x246/0x320
 #1: ffff8881726a4450 (sb_writers#9){.+.+}-{0:0}, at: vfs_write+0x22b/0xba0
 #2: ffff888172b84080 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1d8/0x540
1 lock held by syz.9.5150/25201:
 #0: ffff8881be2460d8 (&type->s_umount_key#85/1){+.+.}-{4:4}, at: sget_fc+0x938/0x1900

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

NMI backtrace for cpu 1
CPU: 1 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 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 25201 Comm: syz.9.5150 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:io_serial_out+0x7c/0xc0
Code: f4 79 fc 44 89 f9 d3 e5 49 83 c6 40 4c 89 f0 48 c1 e8 03 42 80 3c 20 00 74 08 4c 89 f7 e8 1c 87 e7 fc 41 03 2e 89 d8 89 ea ee <5b> 41 5c 41 5e 41 5f 5d c3 cc cc cc cc cc 44 89 f9 80 e1 07 38 c1
RSP: 0018:ffffc9000475f270 EFLAGS: 00000002
RAX: 0000000000000033 RBX: 0000000000000033 RCX: 0000000000000000
RDX: 00000000000003f8 RSI: 000000000002bb51 RDI: 000000000002bb52
RBP: 00000000000003f8 R08: ffff888109dd8237 R09: 1ffff110213bb046
R10: dffffc0000000000 R11: ffffffff854c6ca0 R12: dffffc0000000000
R13: ffffffff9a80de80 R14: ffffffff9a80dec0 R15: 0000000000000000
FS:  00007f3cba8cc6c0(0000) GS:ffff88818dc1d000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f90189bdb10 CR3: 0000000112078000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 serial8250_console_write+0x13b6/0x1ba0
 console_flush_all+0x6ea/0xaf0
 console_unlock+0xd1/0x1c0
 vprintk_emit+0x485/0x560
 _printk+0xdd/0x130
 xfs_printk_level+0x1ae/0x2c0
 xfs_qm_quotacheck+0x636/0x6d0
 xfs_qm_mount_quotas+0x25c/0x660
 xfs_mountfs+0x1bc8/0x2380
 xfs_fs_fill_super+0x115a/0x15a0
 get_tree_bdev_flags+0x430/0x4f0
 vfs_get_tree+0x92/0x2a0
 do_new_mount+0x319/0xdc0
 __se_sys_mount+0x31d/0x420
 do_syscall_64+0x174/0x580
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f3cb999e0ca
Code: 48 c7 c2 e8 ff ff ff f7 d8 64 89 02 b8 ff ff ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 49 89 ca b8 a5 00 00 00 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:00007f3cba8cbe58 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f3cba8cbee0 RCX: 00007f3cb999e0ca
RDX: 00002000000001c0 RSI: 0000200000009640 RDI: 00007f3cba8cbea0
RBP: 00002000000001c0 R08: 00007f3cba8cbee0 R09: 0000000000018040
R10: 0000000000018040 R11: 0000000000000246 R12: 0000200000009640
R13: 00007f3cba8cbea0 R14: 0000000000009736 R15: 0000200000000340
 </TASK>
hpet_rtc_timer_reinit: 7 callbacks suppressed
hpet: Lost 1 RTC interrupts
hpet: Lost 9 RTC interrupts
