INFO: task syz.6.402:7871 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.6.402       state:D stack:28104 pid:7871  tgid:7870  ppid:6095   task_flags:0x400140 flags:0x00080002
Call Trace:
 <TASK>
 __schedule+0x15dd/0x5300
 schedule+0x164/0x360
 schedule_preempt_disabled+0x13/0x30
 rwsem_down_read_slowpath+0x61e/0x920
 down_read+0x99/0x2e0
 super_lock+0x2d6/0x3d0
 __iterate_supers+0x126/0x290
 __ia32_sys_sync+0xa0/0x120
 do_syscall_64+0x14d/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fbe04b9c799
RSP: 002b:00007fbe059e3028 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2
RAX: ffffffffffffffda RBX: 00007fbe04e15fa0 RCX: 00007fbe04b9c799
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007fbe04e15fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fbe04e16038 R14: 00007fbe04e15fa0 R15: 00007ffd330c81e8
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/35:
 #0: ffffffff8e75e560 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180
2 locks held by getty/5634:
 #0: ffff888112fad0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70
 #1: ffffc900035762f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45c/0x13c0
3 locks held by syz-executor/5815:
2 locks held by syz-executor/5818:
2 locks held by syz-executor/5826:
1 lock held by syz.6.402/7871:
 #0: ffff88801b0360e0 (&type->s_umount_key#53){++++}-{4:4}, at: super_lock+0x2d6/0x3d0
1 lock held by syz.1.480/8188:
 #0: ffff88801b0360e0 (&type->s_umount_key#53){++++}-{4:4}, at: super_lock+0x2d6/0x3d0
1 lock held by syz.0.781/9322:
 #0: ffff8881143f60e0 (&type->s_umount_key#53){++++}-{4:4}, at: super_lock+0x289/0x3d0
2 locks held by syz.9.918/9910:
2 locks held by syz.9.919/9913:
2 locks held by syz.2.920/9916:
3 locks held by syz.3.921/9921:

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

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/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: 27 Comm: kworker/u10:0 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
Workqueue: writeback wb_workfn (flush-7:9)
RIP: 0010:sprintf+0x0/0x140
Code: f6 be ff ff ff 7f 4c 89 ff 4c 89 f2 48 89 d9 5b 41 5e 41 5f e9 e1 ba ff ff 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 <f3> 0f 1e fa 55 48 89 e5 41 57 41 56 41 55 41 54 53 48 83 e4 e0 48
RSP: 0018:ffffc90000a26438 EFLAGS: 00000206
RAX: 000000508f350400 RBX: 0000000000000000 RCX: 00000000000a74d2
RDX: 000000000000015a RSI: ffffffff8bcd8a40 RDI: ffffc90000a26580
RBP: ffffc90000a264f0 R08: ffffc90000a265af R09: 0000000000000000
R10: ffffc90000a26580 R11: fffff52000144cb6 R12: 0000000000000000
R13: 0000000000000800 R14: ffffc90000a26700 R15: ffffc90000a26708
FS:  0000000000000000(0000) GS:ffff8882a9463000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fff04cb7e90 CR3: 0000000172838000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 info_print_prefix+0x16b/0x360
 record_print_text+0x176/0x450
 printk_get_next_message+0x29c/0x880
 console_flush_all+0x501/0xb20
 console_unlock+0xd1/0x1c0
 vprintk_emit+0x485/0x560
 _printk+0xdd/0x130
 __ext4_msg+0x2b9/0x2d0
 ext4_do_writepages+0x2d24/0x46e0
 ext4_writepages+0x241/0x3b0
 do_writepages+0x32e/0x550
 __writeback_single_inode+0x133/0x11a0
 writeback_sb_inodes+0x992/0x1a20
 wb_writeback+0x456/0xb70
 wb_workfn+0x414/0xf50
 process_scheduled_works+0xb6e/0x18c0
 worker_thread+0xa53/0xfc0
 kthread+0x388/0x470
 ret_from_fork+0x51e/0xb90
 ret_from_fork_asm+0x1a/0x30
 </TASK>
