INFO: task syz.7.912:13269 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.7.912       state:D stack:24960 pid:13269 tgid:13268 ppid:12833  task_flags:0x400140 flags:0x00080002
Call Trace:
 <TASK>
 __schedule+0x15dd/0x52d0
 schedule+0x164/0x360
 schedule_preempt_disabled+0x13/0x30
 rwsem_down_write_slowpath+0x899/0x1040
 down_write+0x1bc/0x200
 super_lock+0x289/0x3d0
 user_get_super+0xc8/0x120
 __se_sys_quotactl+0x540/0x9e0
 do_syscall_64+0x14d/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f86c1b9c799
RSP: 002b:00007f86bfdf6028 EFLAGS: 00000246 ORIG_RAX: 00000000000000b3
RAX: ffffffffffffffda RBX: 00007f86c1e15fa0 RCX: 00007f86c1b9c799
RDX: 0000000000000000 RSI: 00002000000000c0 RDI: ffffffff80000201
RBP: 00007f86c1c32c99 R08: 0000000000000000 R09: 0000000000000000
R10: 00002000000006c0 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f86c1e16038 R14: 00007f86c1e15fa0 R15: 00007fff9c3e3278
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/34:
 #0: ffffffff8e75e520 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180
2 locks held by kworker/u10:2/40:
2 locks held by kworker/u10:7/1094:
2 locks held by getty/5636:
 #0: ffff88816d1350a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70
 #1: ffffc9000356e2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45c/0x13c0
1 lock held by udevd/6028:
 #0: ffff888107909328 (&sb->s_type->i_mutex_key#11){++++}-{4:4}, at: blkdev_read_iter+0x2f8/0x440
2 locks held by kworker/1:6/6118:
2 locks held by syz-executor/7163:
1 lock held by syz.7.912/13269:
 #0: ffff888114c2e0e0 (&type->s_umount_key#83){++++}-{4:4}, at: super_lock+0x289/0x3d0
1 lock held by syz.0.1182/15269:
 #0: ffff888114c2e0e0 (&type->s_umount_key#83){++++}-{4:4}, at: super_lock+0x2d6/0x3d0
1 lock held by syz.9.1256/16183:
 #0: ffff888114c2e0e0 (&type->s_umount_key#83){++++}-{4:4}, at: super_lock+0x2d6/0x3d0
1 lock held by syz-executor/17061:
 #0: ffffffff8e7647b8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x38d/0x770
2 locks held by syz.3.1500/17562:
2 locks held by syz.3.1500/17564:
2 locks held by syz.8.1502/17599:

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

NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 34 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full) 
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+0xfd9/0x1030
 kthread+0x388/0x470
 ret_from_fork+0x51e/0xb90
 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: 17599 Comm: syz.8.1502 Not tainted syzkaller #0 PREEMPT(full) 
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: fe 84 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 0c 3b ef fc 41 03 2e 89 d8 89 ea ee <5b> 41 5c 41 5e 41 5f 5d e9 c7 95 70 06 cc 44 89 f9 80 e1 07 38 c1
RSP: 0018:ffffc90004467330 EFLAGS: 00000002
RAX: 0000000000000036 RBX: 0000000000000036 RCX: 0000000000000000
RDX: 00000000000003f8 RSI: 000000000000aa82 RDI: 000000000000aa83
RBP: 00000000000003f8 R08: ffff888100b48237 R09: 1ffff11020169046
R10: dffffc0000000000 R11: ffffffff8540a250 R12: dffffc0000000000
R13: ffffffff9a2b6a46 R14: ffffffff9a5ce900 R15: 0000000000000000
FS:  00007f6d2ce016c0(0000) GS:ffff8882a9460000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffffd3a6aa8 CR3: 0000000110024000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 serial8250_console_write+0x140c/0x1ba0
 console_flush_all+0x718/0xb20
 console_unlock+0xd1/0x1c0
 vprintk_emit+0x485/0x560
 _printk+0xdd/0x130
 logfc+0x431/0x520
 fs_param_is_gid+0x1d7/0x420
 __fs_parse+0x3bc/0x730
 isofs_parse_param+0x14c/0x9b0
 vfs_parse_fs_param+0x1a9/0x420
 vfs_parse_monolithic_sep+0x283/0x360
 do_new_mount+0x304/0xd30
 __se_sys_mount+0x31d/0x420
 do_syscall_64+0x14d/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f6d2bf9da0a
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:00007f6d2ce00e58 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f6d2ce00ee0 RCX: 00007f6d2bf9da0a
RDX: 0000200000000140 RSI: 0000200000000000 RDI: 00007f6d2ce00ea0
RBP: 0000200000000140 R08: 00007f6d2ce00ee0 R09: 0000000002000c13
R10: 0000000002000c13 R11: 0000000000000246 R12: 0000200000000000
R13: 00007f6d2ce00ea0 R14: 0000000000000a02 R15: 0000200000000240
 </TASK>
