INFO: task syz-executor:8967 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:22488 pid:8967  tgid:8967  ppid:1      task_flags:0x400140 flags:0x00080002
Call Trace:
 <TASK>
 __schedule+0x17db/0x58f0
 schedule+0x164/0x2b0
 schedule_preempt_disabled+0x13/0x30
 rwsem_down_write_slowpath+0x87d/0x1080
 down_write+0x1bc/0x200
 deactivate_super+0xac/0xe0
 cleanup_mnt+0x3d3/0x460
 task_work_run+0x1d9/0x270
 exit_to_user_mode_loop+0x204/0x770
 do_syscall_64+0x328/0x520
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f75ae39f397
RSP: 002b:00007ffcb939cda8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 00007f75ae4344bb RCX: 00007f75ae39f397
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffcb939ce60
RBP: 00007ffcb939ce60 R08: 00007ffcb939de60 R09: 00000000ffffffff
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffcb939def0
R13: 00007f75ae4344bb R14: 0000000000029168 R15: 00007ffcb939df30
 </TASK>
INFO: task syz.4.428:9289 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.4.428       state:D stack:26152 pid:9289  tgid:9285  ppid:7363   task_flags:0x400040 flags:0x00080002
Call Trace:
 <TASK>
 __schedule+0x17db/0x58f0
 schedule+0x164/0x2b0
 jfs_flush_journal+0x719/0xf50
 jfs_sync_fs+0x7d/0xa0
 dquot_quota_sync+0xd1/0x490
 __iterate_supers+0x282/0x420
 __se_sys_quotactl+0x3a0/0x9f0
 do_syscall_64+0x166/0x520
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f3fec99e159
RSP: 002b:00007f3fed820028 EFLAGS: 00000246 ORIG_RAX: 00000000000000b3
RAX: ffffffffffffffda RBX: 00007f3fecc26180 RCX: 00007f3fec99e159
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff80000100
RBP: 00007f3feca3506b R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f3fecc26218 R14: 00007f3fecc26180 R15: 00007ffefc53ea18
 </TASK>

Showing all locks held in the system:
locks held by pr/ttyS0/16: 2, last CPU#0:
 #0: ffffffff8ec36538 (console_srcu){....}-{0:0}, at: console_srcu_read_lock+0x30/0x60
 #1: ffffffff9ad40278 (&port_lock_key){-...}-{3:3}, at: univ8250_console_device_lock+0x67/0xc0
locks held by khungtaskd/35: 1, last CPU#1:
 #0: ffffffff8ed5c920 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180
locks held by getty/5424: 2, on CPU#0:
 #0: ffff88816b1830a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70
 #1: ffffc9000346e2e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45a/0x1360
locks held by kworker/u8:4/6079: 7, last CPU#0:
 #0: ffff8881012cd940 ((wq_completion)netns){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630
 #1: ffffc900038b7c40 (net_cleanup_work){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630
 #2: ffffffff90246308 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xf5/0x810
 #3: ffff888022d00128 (&dev->mutex){....}-{4:4}, at: devlink_pernet_pre_exit+0x129/0x420
 #4: ffff888022d06258 (&devlink->lock_key#33){+.+.}-{4:4}, at: devlink_pernet_pre_exit+0x142/0x420
 #5: ffffffff90254b80 (rtnl_mutex){+.+.}-{4:4}, at: nsim_destroy+0x173/0x800
 #6: ffffffff8ed62ce8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x2d0/0x770
locks held by syz-executor/8967: 1, on CPU#0:
 #0: ffff888114a5c0e8 (&type->s_umount_key#85){++++}-{4:4}, at: deactivate_super+0xac/0xe0
locks held by syz.4.428/9289: 1, on CPU#1:
 #0: ffff888114a5c0e8 (&type->s_umount_key#85){++++}-{4:4}, at: super_lock+0x2d6/0x3d0
locks held by syz.1.685/11896: 1, on CPU#1:
 #0: ffff888114a5c0e8 (&type->s_umount_key#85){++++}-{4:4}, at: super_lock+0x2d6/0x3d0
locks held by syz.7.694/12098: 1, on CPU#1:
 #0: ffff888114a5c0e8 (&type->s_umount_key#85){++++}-{4:4}, at: super_lock+0x2d6/0x3d0
locks held by syz.7.694/12102: 1, on CPU#0:
 #0: ffff888114a5c0e8 (&type->s_umount_key#85){++++}-{4:4}, at: super_lock+0x2d6/0x3d0
locks held by syz.7.694/12103: 1, on CPU#0:
 #0: ffff888114a5c0e8 (&type->s_umount_key#85){++++}-{4:4}, at: super_lock+0x2d6/0x3d0
locks held by syz.7.694/12104: 1, on CPU#1:
 #0: ffff888114a5c0e8 (&type->s_umount_key#85){++++}-{4:4}, at: super_lock+0x2d6/0x3d0
locks held by syz.7.694/12105: 1, on CPU#1:
 #0: ffff888114a5c0e8 (&type->s_umount_key#85){++++}-{4:4}, at: super_lock+0x2d6/0x3d0
locks held by dhcpcd/12099: 2, on CPU#1:
 #0: ffff8881b9846f80 (&sb->s_type->i_mutex_key#13){+.+.}-{4:4}, at: __sock_release+0x7a/0x1f0
 #1: ffffffff8ed62ce8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x38d/0x770
locks held by syz-executor/12908: 4, last CPU#0:
 #0: ffffffff8ee363f0 (dup_mmap_sem){.+.+}-{0:0}, at: copy_mm+0x10f/0x480
 #1: ffff888114939d38 (&mm->mmap_lock){++++}-{4:4}, at: dup_mmap+0x195/0x1dc0
 #2: ffff8881143c83b8 (&mm->mmap_lock/1){+.+.}-{4:4}, at: dup_mmap+0x221/0x1dc0
 #3: ffffffff8ed5c920 (rcu_read_lock){....}-{1:3}, at: __pte_offset_map+0x29/0x240
locks held by syz-executor/13351: 1, on CPU#1:
 #0: ffffffff90254b80 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0xc10/0x1c30

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

NMI backtrace for cpu 1
CPU: 1 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+0x17d/0x390
 sys_info+0x135/0x170
 watchdog+0xfd7/0x1030
 kthread+0x38b/0x480
 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: 16 Comm: pr/ttyS0 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_in+0x77/0xc0
Code: e8 fe 6c 54 fc 44 89 f9 d3 e3 49 83 c6 40 4c 89 f0 48 c1 e8 03 42 80 3c 20 00 74 08 4c 89 f7 e8 ff 75 c4 fc 41 03 1e 89 da ec <0f> b6 c0 5b 41 5c 41 5e 41 5f c3 cc cc cc cc cc 44 89 f9 80 e1 07
RSP: 0018:ffffc900001578e0 EFLAGS: 00000002
RAX: 1ffffffff35a8060 RBX: 00000000000003fd RCX: 0000000000000000
RDX: 00000000000003fd RSI: 0000000000000000 RDI: 0000000000000020
RBP: dffffc0000000000 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: ffffffff85737eb0 R12: dffffc0000000000
R13: 0000000000000000 R14: ffffffff9ad402a0 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff88818d6cb000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f4fd45556c8 CR3: 0000000112c1d000 CR4: 0000000000352ef0
Call Trace:
 <TASK>
 wait_for_lsr+0xbc/0x2f0
 wait_for_xmitr+0x2c/0x340
 serial8250_console_write+0xc41/0x1200
 nbcon_emit_next_record+0xef5/0x1a90
 nbcon_kthread_func+0x679/0x880
 kthread+0x38b/0x480
 ret_from_fork+0x514/0xb70
 ret_from_fork_asm+0x1a/0x30
 </TASK>
