INFO: task syz-executor:21034 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:22024 pid:21034 tgid:21034 ppid:1      task_flags:0x400140 flags:0x00080002
Call Trace:
 <TASK>
 __schedule+0x17d9/0x56c0
 schedule+0x164/0x2b0
 schedule_preempt_disabled+0x13/0x30
 __mutex_lock+0x7bf/0x1550
 nfsd_shutdown_threads+0x4e/0xd0
 nfsd_umount+0x41/0x60
 deactivate_locked_super+0xbc/0x130
 cleanup_mnt+0x3d3/0x460
 task_work_run+0x1d9/0x270
 exit_to_user_mode_loop+0x1fa/0x730
 do_syscall_64+0x353/0x580
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f58b4d9f257
RSP: 002b:00007ffd35fae618 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 00007f58b4e3445c RCX: 00007f58b4d9f257
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffd35fae6d0
RBP: 00007ffd35fae6d0 R08: 00007ffd35faf6d0 R09: 00000000ffffffff
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffd35faf760
R13: 00007f58b4e3445c R14: 000000000009e5d0 R15: 00007ffd35faf7a0
 </TASK>
INFO: task syz.5.2609:22335 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.5.2609      state:D stack:25480 pid:22335 tgid:22333 ppid:19245  task_flags:0x400140 flags:0x00080006
Call Trace:
 <TASK>
 __schedule+0x17d9/0x56c0
 schedule+0x164/0x2b0
 schedule_preempt_disabled+0x13/0x30
 rwsem_down_read_slowpath+0x6ba/0x920
 down_read+0x9c/0x330
 super_lock+0x2d6/0x3d0
 __iterate_supers+0x120/0x240
 __ia32_sys_sync+0xa0/0x120
 do_syscall_64+0x174/0x580
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f2cd799e019
RSP: 002b:00007f2cd877f028 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2
RAX: ffffffffffffffda RBX: 00007f2cd7c25fa0 RCX: 00007f2cd799e019
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007f2cd7c25fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f2cd7c26038 R14: 00007f2cd7c25fa0 R15: 00007ffc6fbf7a58
 </TASK>

Showing all locks held in the system:
1 lock held by pool_workqueue_/3:
 #0: ffffffff8eb5ffa8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x38d/0x770
1 lock held by khungtaskd/35:
 #0: ffffffff8eb59ca0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180
1 lock held by dhcpcd/5354:
2 locks held by getty/5438:
 #0: ffff88810f52c0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70
 #1: ffffc900034732e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45a/0x1360
3 locks held by kworker/0:6/6371:
3 locks held by syz.9.1693/16908:
 #0: ffff88817211f4f0 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x246/0x320
 #1: ffff888110c0c450 (sb_writers#12){.+.+}-{0:0}, at: vfs_write+0x22b/0xba0
 #2: ffffffff8ee8e6e0 (nfsd_mutex){+.+.}-{4:4}, at: write_ports+0xb5/0xd10
3 locks held by kworker/u8:5/19713:
2 locks held by syz-executor/21034:
 #0: ffff88816dad80d8 (&type->s_umount_key#54){++++}-{4:4}, at: deactivate_super+0xa9/0xe0
 #1: ffffffff8ee8e6e0 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x4e/0xd0
2 locks held by kworker/u9:20/21329:
 #0: ffff888169461140 ((wq_completion)iou_exit){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0
 #1: ffffc900061dfc40 ((work_completion)(&ctx->exit_work)){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0
3 locks held by kworker/0:15/21494:
4 locks held by kworker/u10:18/21650:
2 locks held by kworker/u10:19/21651:
 #0: ffff888169461140 ((wq_completion)iou_exit){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0
 #1: ffffc900079bfc40 ((work_completion)(&ctx->exit_work)){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0
1 lock held by syz.5.2609/22335:
 #0: ffff88816dad80d8 (&type->s_umount_key#54){++++}-{4:4}, at: super_lock+0x2d6/0x3d0
2 locks held by syz.3.3064/24580:
 #0: ffffffff9009dde8 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40
 #1: ffffffff8ee8e6e0 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_unlock_export_doit+0x2cf/0x530
1 lock held by syz.0.3315/25774:
 #0: ffff88816dad80d8 (&type->s_umount_key#54){++++}-{4:4}, at: super_lock+0x2d6/0x3d0
2 locks held by syz-executor/26119:
 #0: ffffffff9002d500 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x8a3/0x1bd0
 #1: ffff88811618d610 (&wg->device_update_lock){+.+.}-{4:4}, at: wg_open+0x227/0x420

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

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+0x17a/0x380
 sys_info+0x135/0x170
 watchdog+0xfd7/0x1030
 kthread+0x388/0x470
 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: 5599 Comm: syz-executor 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:asm_sysvec_apic_timer_interrupt+0x0/0x20
Code: b6 79 d1 0a e9 81 06 00 00 90 f3 0f 1e fa 0f 1f 00 fc 6a ff e8 31 05 00 00 48 89 c4 48 89 e7 e8 c6 78 d1 0a e9 61 06 00 00 90 <f3> 0f 1e fa 0f 1f 00 fc 6a ff e8 11 05 00 00 48 89 c4 48 89 e7 e8
RSP: 0018:ffffc9000482f958 EFLAGS: 00000006
RAX: 00000000001f1839 RBX: ffff88812103bf20 RCX: 0000000080000001
RDX: 0000000000000000 RSI: ffffffff8e22dd7f RDI: ffffffff8c4be180
RBP: ffffc9000482f9d0 R08: ffffffff90578e37 R09: 1ffffffff20af1c6
R10: dffffc0000000000 R11: fffffbfff20af1c7 R12: ffff8881721e1e00
R13: ffff88812103bee8 R14: dffffc0000000000 R15: 1ffff110242077e4
FS:  000055557eae7540(0000) GS:ffff88818d94d000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005566dbfe3680 CR3: 000000010179a000 CR4: 00000000000006f0
Call Trace:
 <TASK>
RIP: 0010:finish_task_switch+0x417/0xc60
Code: 04 00 00 41 c7 84 24 20 0e 00 00 00 00 00 00 0f 1f 44 00 00 49 83 c4 48 4c 89 e7 e8 13 c0 3e 0a e8 ce a9 39 00 fb 4c 8b 65 c8 <49> 8d bc 24 00 17 00 00 48 89 f8 48 c1 e8 03 42 0f b6 04 30 84 c0
RSP: 0018:ffffc9000482f980 EFLAGS: 00000206
 __schedule+0x17e1/0x56c0
 schedule+0x164/0x2b0
 do_nanosleep+0x21e/0x6a0
 hrtimer_nanosleep+0x18f/0x3a0
 __se_sys_clock_nanosleep+0x35b/0x3b0
 do_syscall_64+0x174/0x580
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fa106b59197
Code: 48 89 fa 4c 89 df e8 a8 56 00 00 8b 93 08 03 00 00 59 5e 48 83 f8 fc 74 1a 5b c3 0f 1f 84 00 00 00 00 00 48 8b 44 24 10 0f 05 <5b> c3 0f 1f 80 00 00 00 00 83 e2 39 83 fa 08 75 de e8 23 ff ff ff
RSP: 002b:00007ffcf8b9f680 EFLAGS: 00000202 ORIG_RAX: 00000000000000e6
RAX: ffffffffffffffda RBX: 000055557eae7540 RCX: 00007fa106b59197
RDX: 00007ffcf8b9f6c0 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007ffcf8b9fba0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000004
R13: 00007ffcf8b9f6fc R14: 00007ffcf8b9f790 R15: 0000000000000000
 </TASK>
