INFO: task syz.4.695:12050 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.4.695       state:D stack:26568 pid:12050 tgid:12048 ppid:11797  task_flags:0x400040 flags:0x00080002
Call Trace:
 <TASK>
 __schedule+0x1821/0x5740
 schedule+0x164/0x360
 schedule_preempt_disabled+0x13/0x30
 rwsem_down_read_slowpath+0x6d9/0x940
 down_read+0x99/0x2e0
 super_lock+0x2d6/0x3d0
 user_get_super+0xc8/0x120
 __se_sys_quotactl+0x540/0x9e0
 do_syscall_64+0x15f/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fbac859ce59
RSP: 002b:00007fbac9449028 EFLAGS: 00000246 ORIG_RAX: 00000000000000b3
RAX: ffffffffffffffda RBX: 00007fbac8816090 RCX: 00007fbac859ce59
RDX: 0000000000000000 RSI: 00002000000003c0 RDI: ffffffff80000800
RBP: 00007fbac8632d6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000200000000540 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fbac8816128 R14: 00007fbac8816090 R15: 00007ffff4804898
 </TASK>
INFO: task syz.0.713:12142 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.713       state:D stack:19576 pid:12142 tgid:12141 ppid:10715  task_flags:0x400140 flags:0x00080002
Call Trace:
 <TASK>
 __schedule+0x1821/0x5740
 schedule+0x164/0x360
 schedule_preempt_disabled+0x13/0x30
 rwsem_down_read_slowpath+0x6d9/0x940
 down_read+0x99/0x2e0
 super_lock+0x2d6/0x3d0
 __iterate_supers+0x126/0x250
 __ia32_sys_sync+0xa0/0x120
 do_syscall_64+0x15f/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fe87f99ce59
RSP: 002b:00007fe87dbf6028 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2
RAX: ffffffffffffffda RBX: 00007fe87fc15fa0 RCX: 00007fe87f99ce59
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007fe87fc15fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fe87fc16038 R14: 00007fe87fc15fa0 R15: 00007ffccaeac308
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/35:
 #0: ffffffff8e95cd60 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180
2 locks held by getty/5440:
 #0: ffff88810ac600a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70
 #1: ffffc900034732e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45c/0x13a0
1 lock held by udevd/6011:
 #0: ffff88816bcfc350 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_release+0x1a9/0x650
2 locks held by syz-executor/6301:
2 locks held by syz-executor/10816:
1 lock held by syz.4.695/12050:
 #0: ffff888118d8e0d8 (&type->s_umount_key#58){++++}-{4:4}, at: super_lock+0x2d6/0x3d0
1 lock held by syz.0.713/12142:
 #0: ffff888118d8e0d8 (&type->s_umount_key#58){++++}-{4:4}, at: super_lock+0x2d6/0x3d0
1 lock held by syz-executor/12197:
 #0: ffffffff8e963068 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x2d0/0x770
1 lock held by syz.1.725/12242:
 #0: ffff888118d8e0d8 (&type->s_umount_key#58){++++}-{4:4}, at: super_lock+0x2d6/0x3d0
1 lock held by syz.3.736/12494:
 #0: ffff888118d8e0d8 (&type->s_umount_key#58){++++}-{4:4}, at: super_lock+0x2d6/0x3d0
1 lock held by syz.3.736/12495:
 #0: ffff888118d8e0d8 (&type->s_umount_key#58){++++}-{4:4}, at: super_lock+0x2d6/0x3d0
1 lock held by syz.3.736/12496:
 #0: ffff888118d8e0d8 (&type->s_umount_key#58){++++}-{4:4}, at: super_lock+0x2d6/0x3d0
1 lock held by syz.3.736/12497:
 #0: ffff888118d8e0d8 (&type->s_umount_key#58){++++}-{4:4}, at: super_lock+0x2d6/0x3d0
1 lock held by syz.3.736/12498:
 #0: ffff888118d8e0d8 (&type->s_umount_key#58){++++}-{4:4}, at: super_lock+0x2d6/0x3d0
1 lock held by syz.3.736/12499:
 #0: ffff888118d8e0d8 (&type->s_umount_key#58){++++}-{4:4}, at: super_lock+0x2d6/0x3d0
1 lock held by syz.7.955/14288:
 #0: ffff888118d8e0d8 (&type->s_umount_key#58){++++}-{4:4}, at: super_lock+0x2d6/0x3d0
1 lock held by syz.5.978/14418:

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

NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 35 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+0xfd3/0x1030
 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: 12197 Comm: syz-executor 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:__lock_acquire+0x197b/0x2cf0
Code: 14 25 ff 0f 00 00 39 05 8f 39 9f 12 73 06 89 05 87 39 9f 12 48 8b 02 48 89 df 4c 39 e8 0f 84 2c fe ff ff 4c 89 60 30 48 8b 00 <4c> 39 e8 75 f4 48 89 df e9 18 fe ff ff 48 89 fb 48 c7 c7 10 af 82
RSP: 0018:ffffc9000ff26e78 EFLAGS: 00000006
RAX: ffffffff96ca9d68 RBX: 00000000000003dd RCX: 000000000000002f
RDX: ffffffff96c55c18 RSI: ffff88810e338c58 RDI: 00000000000003dd
RBP: d85b024586d2118b R08: ffffc9000ff26e40 R09: 0000000000000020
R10: dffffc0000000000 R11: ffffffff81a21f90 R12: ffffffff96c7c728
R13: ffffffff93e2d500 R14: ffff88810e338000 R15: 000000000000002e
FS:  0000555587c20500(0000) GS:ffff8882a928d000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000555587c3ba28 CR3: 000000002a758000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 lock_acquire+0x106/0x350
 seqcount_lockdep_reader_access+0x55/0x100
 ktime_get_update_offsets_now+0x5d/0x3e0
 __hrtimer_rearm_deferred+0xe1/0x450
 finish_task_switch+0x3f0/0xbe0
 __schedule+0x1829/0x5740
 preempt_schedule_irq+0x4d/0xa0
 irqentry_exit+0x14f/0x760
 asm_sysvec_call_function_single+0x1a/0x20
RIP: 0010:seqcount_lockdep_reader_access+0xec/0x100
Code: 00 75 11 e8 c6 e3 12 00 4d 85 ff 75 16 e8 bc e3 12 00 eb 15 e8 b5 e3 12 00 e8 00 e7 f5 09 4d 85 ff 74 ea e8 a6 e3 12 00 fb 5b <41> 5e 41 5f c3 cc cc cc cc cc 66 2e 0f 1f 84 00 00 00 00 00 90 90
RSP: 0018:ffffc9000ff274f0 EFLAGS: 00000293
RAX: ffffffff81b2de2a RBX: 0000000000000000 RCX: ffff88810e338000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc9000ff278b0 R08: ffffffff9030b6f7 R09: 1ffffffff20616de
R10: dffffc0000000000 R11: fffffbfff20616df R12: fffff52001fe4ed0
R13: ffff88810ad84000 R14: ffffffff81b2e285 R15: 0000000000000200
 ktime_get+0x45/0x220
 f2fs_write_checkpoint+0x304/0x26a0
 f2fs_issue_checkpoint+0x456/0x790
 sync_filesystem+0x1cf/0x230
 generic_shutdown_super+0x77/0x2d0
 kill_block_super+0x44/0x90
 kill_f2fs_super+0x402/0x730
 deactivate_locked_super+0xbc/0x130
 cleanup_mnt+0x437/0x4d0
 task_work_run+0x1d9/0x270
 exit_to_user_mode_loop+0xf3/0x4d0
 do_syscall_64+0x33e/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f5d6c19e097
Code: a2 c7 05 5c 06 25 00 00 00 00 00 eb 96 e8 e1 12 00 00 90 31 f6 e9 09 00 00 00 66 0f 1f 84 00 00 00 00 00 b8 a6 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 01 c3 48 c7 c2 e8 ff ff ff f7 d8 64 89 02 b8
RSP: 002b:00007ffc45bd9de8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 00007f5d6c2321ca RCX: 00007f5d6c19e097
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffc45bd9ea0
RBP: 00007ffc45bd9ea0 R08: 00007ffc45bdaea0 R09: 00000000ffffffff
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffc45bdaf30
R13: 00007f5d6c2321ca R14: 000000000007c495 R15: 00007ffc45bdaf70
 </TASK>
