INFO: task syz-executor:18215 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-executor    state:D stack:22608 pid:18215 tgid:18215 ppid:1      task_flags:0x400140 flags:0x00080002
Call Trace:
 <TASK>
 __schedule+0x17db/0x58f0
 schedule+0x164/0x2b0
 schedule_preempt_disabled+0x13/0x30
 __mutex_lock+0x7c1/0x1550
 nfsd_shutdown_threads+0x4e/0xd0
 nfsd_umount+0x41/0x60
 deactivate_locked_super+0xbc/0x110
 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: 0033:0x7f473079f397
RSP: 002b:00007fffe4a97d68 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 00007f47308344bb RCX: 00007f473079f397
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007fffe4a97e20
RBP: 00007fffe4a97e20 R08: 00007fffe4a98e20 R09: 00000000ffffffff
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fffe4a98eb0
R13: 00007f47308344bb R14: 000000000006351f R15: 00007fffe4a98ef0
 </TASK>
INFO: task syz-executor:18401 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-executor    state:D stack:22568 pid:18401 tgid:18401 ppid:1      task_flags:0x400140 flags:0x00080002
Call Trace:
 <TASK>
 __schedule+0x17db/0x58f0
 schedule+0x164/0x2b0
 schedule_preempt_disabled+0x13/0x30
 __mutex_lock+0x7c1/0x1550
 nfsd_shutdown_threads+0x4e/0xd0
 nfsd_umount+0x41/0x60
 deactivate_locked_super+0xbc/0x110
 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: 0033:0x7f3741f9f397
RSP: 002b:00007ffef2421008 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 00007f37420344bb RCX: 00007f3741f9f397
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffef24210c0
RBP: 00007ffef24210c0 R08: 00007ffef24220c0 R09: 00000000ffffffff
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffef2422150
R13: 00007f37420344bb R14: 000000000006366c R15: 00007ffef2422190
 </TASK>
INFO: task syz-executor:18496 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-executor    state:D stack:22672 pid:18496 tgid:18496 ppid:1      task_flags:0x400140 flags:0x00080002
Call Trace:
 <TASK>
 __schedule+0x17db/0x58f0
 schedule+0x164/0x2b0
 schedule_preempt_disabled+0x13/0x30
 __mutex_lock+0x7c1/0x1550
 nfsd_shutdown_threads+0x4e/0xd0
 nfsd_umount+0x41/0x60
 deactivate_locked_super+0xbc/0x110
 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: 0033:0x7f579f79f397
RSP: 002b:00007ffc0eafdec8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 00007f579f8344bb RCX: 00007f579f79f397
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffc0eafdf80
RBP: 00007ffc0eafdf80 R08: 00007ffc0eafef80 R09: 00000000ffffffff
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffc0eaff010
R13: 00007f579f8344bb R14: 0000000000065598 R15: 00007ffc0eaff050
 </TASK>

Showing all locks held in the system:
locks held by pr/ttyS0/16: 2, last CPU#0:
 #0: ffffffff8ec362b8 (console_srcu){....}-{0:0}, at: console_srcu_read_lock+0x30/0x60
 #1: ffffffff9ad31098 (&port_lock_key){-...}-{3:3}, at: univ8250_console_device_lock+0x67/0xc0
locks held by khungtaskd/35: 1, last CPU#1:
 #0: ffffffff8ed5c6e0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180
locks held by getty/5422: 2, on CPU#0:
 #0: ffff88816e5730a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70
 #1: ffffc900034762e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45a/0x1360
locks held by syz.1.3751/14718: 3, on CPU#1:
 #0: ffff888114ae46f0 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x246/0x320
 #1: ffff888110ebc460 (sb_writers#29){.+.+}-{0:0}, at: vfs_write+0x22b/0xba0
 #2: ffffffff8f09e400 (nfsd_mutex){+.+.}-{4:4}, at: write_threads+0x3b1/0x610
locks held by kworker/0:7/17163: 2, last CPU#0:
 #0: ffff88819db6d140 ((wq_completion)wg-crypt-wg0#10){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630
 #1: ffffc900034dfc40 ((work_completion)(&peer->transmit_packet_work)){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630
locks held by syz-executor/18215: 2, on CPU#1:
 #0: ffff88819e5260e8 (&type->s_umount_key#111){++++}-{4:4}, at: deactivate_super+0xac/0xe0
 #1: ffffffff8f09e400 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x4e/0xd0
locks held by syz-executor/18401: 2, on CPU#1:
 #0: ffff88810f9240e8 (&type->s_umount_key#111){++++}-{4:4}, at: deactivate_super+0xac/0xe0
 #1: ffffffff8f09e400 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x4e/0xd0
locks held by syz-executor/18496: 2, on CPU#1:
 #0: ffff888172ca80e8 (&type->s_umount_key#111){++++}-{4:4}, at: deactivate_super+0xac/0xe0
 #1: ffffffff8f09e400 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x4e/0xd0
locks held by syz.0.5757/20143: 1, on CPU#1:
 #0: ffff88819e5260e8 (&type->s_umount_key#111){++++}-{4:4}, at: super_lock+0x2d6/0x3d0
locks held by syz.1.5885/20425: 1, on CPU#1:
 #0: ffff88819e5260e8 (&type->s_umount_key#111){++++}-{4:4}, at: super_lock+0x2d6/0x3d0
locks held by syz.4.7083/23280: 2, on CPU#1:
 #0: ffffffff902c1b68 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40
 #1: ffffffff8f09e400 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_threads_get_doit+0x1c0/0x790
locks held by syz.5.7516/24285: 1, last CPU#0:
 #0: ffff88810dc49d38 (&mm->mmap_lock){++++}-{4:4}, at: exit_mmap+0x1a4/0x9f0
locks held by syz-executor/24352: 3, last CPU#1:
 #0: ffff88810f606460 (sb_writers#5){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90
 #1: ffff8881bb203ed8 (&type->i_mutex_dir_key#5/1){+.+.}-{4:4}, at: filename_create+0x200/0x370
 #2: ffffffff8f4ef8f8 (tomoyo_ss){.+.+}-{0:0}, at: tomoyo_path_perm+0x251/0x560

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

NMI backtrace for cpu 1
CPU: 1 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+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 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
RIP: 0010:io_serial_out+0x7c/0xc0
Code: e0 55 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 9c aa c5 fc 41 03 2e 89 d8 89 ea ee <5b> 41 5c 41 5e 41 5f 5d e9 47 e2 74 06 cc 44 89 f9 80 e1 07 38 c1
RSP: 0018:ffffc90000157900 EFLAGS: 00000002
RAX: 0000000000000020 RBX: 0000000000000020 RCX: 0000000000000000
RDX: 00000000000003f8 RSI: 0000000000000000 RDI: 0000000000000020
RBP: 00000000000003f8 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: ffffffff8571d5d0 R12: dffffc0000000000
R13: 0000000000000020 R14: ffffffff9ad310c0 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff88818d6da000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c3fdd75 CR3: 000000000eb48000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 __serial8250_console_fifo_write+0x1e6/0x3e0
 serial8250_console_write+0xaa1/0x1200
 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>
