INFO: task syz.2.619:11439 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.2.619       state:D stack:24776 pid:11439 tgid:11438 ppid:10674  task_flags:0x400140 flags:0x00080002
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
 __se_sys_quotactl+0x3a0/0x9a0
 do_syscall_64+0x174/0x580
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f8ba939e019
RSP: 002b:00007f8baa2ef028 EFLAGS: 00000246 ORIG_RAX: 00000000000000b3
RAX: ffffffffffffffda RBX: 00007f8ba9625fa0 RCX: 00007f8ba939e019
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff80000100
RBP: 00007f8ba943500c R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f8ba9626038 R14: 00007f8ba9625fa0 R15: 00007fff726bf208
 </TASK>

Showing all locks held in the system:
3 locks held by kworker/u8:0/12:
4 locks held by kworker/u8:1/13:
 #0: ffff8881012d5940 ((wq_completion)netns){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0
 #1: ffffc90000127c40 (net_cleanup_work){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0
 #2: ffffffff9001e4c8 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xf5/0x810
 #3: ffff88823c63b160 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2d/0x160
1 lock held by khungtaskd/35:
 #0: ffffffff8eb59c60 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180
2 locks held by dhcpcd/5355:
 #0: ffffffff9009d8e8 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40
 #1: ffffffff9002d080 (rtnl_mutex){+.+.}-{4:4}, at: nl80211_pre_doit+0x5e/0x890
2 locks held by getty/5441:
 #0: ffff888176b1d0a0 (&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/u8:2/5481:
 #0: ffff88810e38c940 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0
 #1: ffffc9000447fc40 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0
 #2: ffffffff9002d080 (rtnl_mutex){+.+.}-{4:4}, at: addrconf_dad_work+0x116/0x15c0
3 locks held by syz-executor/8938:
1 lock held by syz.2.619/11439:
 #0: ffff8881123380d8 (&type->s_umount_key#63){++++}-{4:4}, at: super_lock+0x2d6/0x3d0
3 locks held by kworker/u10:7/12447:
 #0: ffff8881000ac140 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0
 #1: ffffc9000341fc40 ((linkwatch_work).work){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0
 #2: ffffffff9002d080 (rtnl_mutex){+.+.}-{4:4}, at: linkwatch_event+0xe/0x60
3 locks held by syz-executor/14037:
 #0: ffffffff9002d080 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x8a3/0x1bd0
 #1: ffff888174960e70 (&dev_instance_lock_key#23){+.+.}-{4:4}, at: do_setlink+0x3d4/0x4670
 #2: ffffffff8eb5ff68 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x38d/0x770
1 lock held by syz-executor/14125:
 #0: ffffffff8eb5ff68 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x2d0/0x770
1 lock held by syz.6.855/14180:
 #0: ffff88810a47cea0 (&hdev->req_lock){+.+.}-{4:4}, at: hci_unregister_dev+0x22a/0x5b0

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

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/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 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 14037 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:io_serial_in+0x77/0xc0
Code: e8 7e 5b 60 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 5f ee cd 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:ffffc90008246698 EFLAGS: 00000006
RAX: 1ffffffff355b405 RBX: 00000000000003f9 RCX: 0000000000000000
RDX: 00000000000003f9 RSI: 0000000000000000 RDI: 0000000000000020
RBP: ffffc90008246830 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: ffffffff8566a5b0 R12: dffffc0000000000
R13: ffffffff9aada0a0 R14: ffffffff9aada0e0 R15: 0000000000000000
FS:  0000555582b97500(0000) GS:ffff8882a8f51000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2df1aff8 CR3: 000000010f1ac000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 serial8250_console_write+0x503/0x1ba0
 console_flush_all+0x6ea/0xaf0
 console_unlock+0xd1/0x1c0
 vprintk_emit+0x485/0x560
 _printk+0xdd/0x130
 vlan_device_event+0x13e6/0x1580
 notifier_call_chain+0x1a5/0x3d0
 __dev_notify_flags+0x1aa/0x310
 netif_change_flags+0xde/0x1b0
 do_setlink+0xdd6/0x4670
 rtnl_newlink+0x15c2/0x1bd0
 rtnetlink_rcv_msg+0x802/0xc00
 netlink_rcv_skb+0x226/0x4a0
 netlink_unicast+0x7bb/0x940
 netlink_sendmsg+0x813/0xb40
 sock_sendmsg_nosec+0x13a/0x180
 __sys_sendto+0x408/0x5a0
 __x64_sys_sendto+0xde/0x100
 do_syscall_64+0x174/0x580
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fa02495e84e
Code: 08 0f 85 a5 a8 ff ff 49 89 fb 48 89 f0 48 89 d7 48 89 ce 4c 89 c2 4d 89 ca 4c 8b 44 24 08 4c 8b 4c 24 10 4c 89 5c 24 08 0f 05 <c3> 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 80 00 00 00 00 48 83 ec 08
RSP: 002b:00007ffd0ba1c288 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 0000555582b97500 RCX: 00007fa02495e84e
RDX: 0000000000000030 RSI: 00007fa025753610 RDI: 0000000000000006
RBP: 0000000000000001 R08: 00007ffd0ba1c304 R09: 000000000000000c
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000006
R13: 0000000000000000 R14: 00007fa025753610 R15: 0000000000000000
 </TASK>
