INFO: task syz-executor:6063 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor    state:D stack:18856 pid:6063  tgid:6063  ppid:1      task_flags:0x400140 flags:0x00004004
Call Trace:
 <TASK>
 __schedule+0x1798/0x4cc0
 schedule+0x165/0x360
 wb_wait_for_completion+0x15f/0x260
 __writeback_inodes_sb_nr+0x1f6/0x250
 sync_filesystem+0xa3/0x230
 generic_shutdown_super+0x6f/0x2c0
 bch2_kill_sb+0x41/0x50
 deactivate_locked_super+0xbc/0x130
 cleanup_mnt+0x425/0x4c0
 task_work_run+0x1d4/0x260
 exit_to_user_mode_loop+0xec/0x110
 do_syscall_64+0x2bd/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f3c3198fed7
RSP: 002b:00007ffc6d0c75a8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 00007f3c31a11c05 RCX: 00007f3c3198fed7
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffc6d0c7660
RBP: 00007ffc6d0c7660 R08: 0000000000000000 R09: 0000000000000000
R10: 00000000ffffffff R11: 0000000000000246 R12: 00007ffc6d0c86f0
R13: 00007f3c31a11c05 R14: 00000000000238da R15: 00007ffc6d0c8730
 </TASK>
INFO: task syz.4.275:7700 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.4.275       state:D stack:25128 pid:7700  tgid:7699  ppid:7039   task_flags:0x400140 flags:0x00004004
Call Trace:
 <TASK>
 __schedule+0x1798/0x4cc0
 schedule+0x165/0x360
 schedule_preempt_disabled+0x13/0x30
 rwsem_down_read_slowpath+0x5fd/0x8f0
 down_read+0x98/0x2e0
 super_lock+0x2a9/0x3b0
 __iterate_supers+0x126/0x290
 ksys_sync+0x94/0x150
 __ia32_sys_sync+0xe/0x20
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fcb32b8eba9
RSP: 002b:00007fcb33a30038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2
RAX: ffffffffffffffda RBX: 00007fcb32dd5fa0 RCX: 00007fcb32b8eba9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007fcb32dd5fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fcb32dd6038 R14: 00007fcb32dd5fa0 R15: 00007ffc36938538
 </TASK>
INFO: task syz.4.275:7702 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.4.275       state:D stack:28936 pid:7702  tgid:7699  ppid:7039   task_flags:0x400040 flags:0x00004004
Call Trace:
 <TASK>
 __schedule+0x1798/0x4cc0
 schedule+0x165/0x360
 schedule_preempt_disabled+0x13/0x30
 rwsem_down_read_slowpath+0x5fd/0x8f0
 down_read+0x98/0x2e0
 super_lock+0x2a9/0x3b0
 __iterate_supers+0x126/0x290
 ksys_sync+0x94/0x150
 __ia32_sys_sync+0xe/0x20
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fcb32b8eba9
RSP: 002b:00007fcb33a0f038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2
RAX: ffffffffffffffda RBX: 00007fcb32dd6090 RCX: 00007fcb32b8eba9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007fcb32dd6090 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fcb32dd6128 R14: 00007fcb32dd6090 R15: 00007ffc36938538
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/34:
 #0: ffffffff8e13a0e0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180
2 locks held by kworker/u9:3/70:
 #0: ffff88810169f948 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0
 #1: ffffc9000173fbc0 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0
2 locks held by getty/5681:
 #0: ffff88811033c0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70
 #1: ffffc900029032f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400
1 lock held by syz-executor/6063:
 #0: ffff8880334840e0 (&type->s_umount_key#56){++++}-{4:4}, at: deactivate_super+0xa9/0xe0
1 lock held by syz.4.275/7700:
 #0: ffff8880334840e0 (&type->s_umount_key#56){++++}-{4:4}, at: super_lock+0x2a9/0x3b0
1 lock held by syz.4.275/7702:
 #0: ffff8880334840e0 (&type->s_umount_key#56){++++}-{4:4}, at: super_lock+0x2a9/0x3b0
1 lock held by syz.5.306/7909:
 #0: ffff8880334840e0 (&type->s_umount_key#56){++++}-{4:4}, at: super_lock+0x2a9/0x3b0
1 lock held by syz.0.482/9172:
 #0: ffff8880334840e0 (&type->s_umount_key#56){++++}-{4:4}, at: super_lock+0x2a9/0x3b0
1 lock held by syz.3.548/9680:
 #0: ffff8880334840e0 (&type->s_umount_key#56){++++}-{4:4}, at: super_lock+0x2a9/0x3b0
1 lock held by syz.3.548/9681:
 #0: ffff8880334840e0 (&type->s_umount_key#56){++++}-{4:4}, at: super_lock+0x2a9/0x3b0
1 lock held by syz.4.603/9954:
 #0: ffff8880334840e0 (&type->s_umount_key#56){++++}-{4:4}, at: super_lock+0x2a9/0x3b0
1 lock held by syz.4.603/9955:
 #0: ffff8880334840e0 (&type->s_umount_key#56){++++}-{4:4}, at: super_lock+0x2a9/0x3b0
1 lock held by syz.6.622/10268:
 #0: ffff8880334840e0 (&type->s_umount_key#56){++++}-{4:4}, at: super_lock+0x2a9/0x3b0
4 locks held by syz.7.693/10909:
 #0: ffff88811aaf7470 (&fc->uapi_mutex){+.+.}-{4:4}, at: __se_sys_fsconfig+0x758/0x8d0
 #1: ffff88810a3b80e0 (&type->s_umount_key#31){++++}-{4:4}, at: vfs_fsconfig_locked+0x169/0x320
 #2: ffff88810a3beb98 (&sbi->s_writepages_rwsem){++++}-{0:0}, at: ext4_reconfigure+0xa85/0x2cc0
 #3: ffffffff8e13fb78 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x3b9/0x730
1 lock held by syz.9.694/10911:
 #0: ffff88804b039f98 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2a/0x140
4 locks held by syz.8.695/10915:

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

NMI backtrace for cpu 1
CPU: 1 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+0x189/0x250
 nmi_cpu_backtrace+0x39e/0x3d0
 nmi_trigger_cpumask_backtrace+0x17a/0x300
 watchdog+0xf93/0xfe0
 kthread+0x711/0x8a0
 ret_from_fork+0x439/0x7d0
 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: 10909 Comm: syz.7.693 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: eb 6f 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 5c 5e d3 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:ffffc900047cf3f0 EFLAGS: 00000002
RAX: 0000000000000030 RBX: 0000000000000030 RCX: 0000000000000000
RDX: 00000000000003f8 RSI: 0000000000001830 RDI: 0000000000001831
RBP: 00000000000003f8 R08: ffff888020058237 R09: 1ffff1100400b046
R10: dffffc0000000000 R11: ffffffff854fd130 R12: dffffc0000000000
R13: ffffffff99b008c5 R14: ffffffff99df5440 R15: 0000000000000000
FS:  00007f0c23cd56c0(0000) GS:ffff8880b8615000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055558698c5c8 CR3: 0000000104c90000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 serial8250_console_write+0x1410/0x1ba0
 console_flush_all+0x728/0xc40
 console_unlock+0xc4/0x270
 vprintk_emit+0x5b7/0x7a0
 _printk+0xcf/0x120
 __ext4_msg+0x293/0x2a0
 ext4_reconfigure+0x168f/0x2cc0
 reconfigure_super+0x227/0x890
 vfs_fsconfig_locked+0x171/0x320
 __se_sys_fsconfig+0x78e/0x8d0
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f0c22d8eba9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f0c23cd5038 EFLAGS: 00000246 ORIG_RAX: 00000000000001af
RAX: ffffffffffffffda RBX: 00007f0c22fd5fa0 RCX: 00007f0c22d8eba9
RDX: 0000000000000000 RSI: 0000000000000007 RDI: 0000000000000007
RBP: 00007f0c22e11e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f0c22fd6038 R14: 00007f0c22fd5fa0 R15: 00007fffb6617b28
 </TASK>
