INFO: task syz.7.508:9878 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.7.508       state:D stack:25128 pid:9878  tgid:9877  ppid:9455   task_flags:0x400040 flags:0x00004004
Call Trace:
 <TASK>
 __schedule+0x1798/0x4cc0
 schedule+0x165/0x360
 schedule_preempt_disabled+0x13/0x30
 rwsem_down_read_slowpath+0x5fd/0x8f0
 down_read+0x98/0x2e0
 super_lock+0x2a9/0x3b0
 user_get_super+0xc8/0x120
 __se_sys_quotactl+0x4da/0x950
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f536f18ebe9
RSP: 002b:00007f53700ce038 EFLAGS: 00000246 ORIG_RAX: 00000000000000b3
RAX: ffffffffffffffda RBX: 00007f536f3c5fa0 RCX: 00007f536f18ebe9
RDX: 0000000000000000 RSI: 0000200000000040 RDI: ffffffff80000801
RBP: 00007f536f211e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000200000000280 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f536f3c6038 R14: 00007f536f3c5fa0 R15: 00007fffa47539e8
 </TASK>

Showing all locks held in the system:
4 locks held by kworker/u8:0/12:
1 lock held by khungtaskd/34:
 #0: ffffffff8e139ee0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180
3 locks held by kworker/1:1/47:
 #0: ffff88801a480d48 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0
 #1: ffffc9000075fbc0 ((work_completion)(&data->fib_event_work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0
 #2: ffff88811e43f240 (&data->fib_lock){+.+.}-{4:4}, at: nsim_fib_event_work+0x26b/0x3180
2 locks held by getty/5673:
 #0: ffff8880201960a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70
 #1: ffffc900029062f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400
3 locks held by kworker/u8:2/5694:
 #0: ffff888022653148 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0
 #1: ffffc90002fafbc0 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0
 #2: ffffffff8f538888 (rtnl_mutex){+.+.}-{4:4}, at: addrconf_dad_work+0x112/0x14b0
3 locks held by kworker/1:6/5919:
 #0: ffff88801a480d48 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0
 #1: ffffc90003aefbc0 (deferred_process_work){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0
 #2: ffffffff8f538888 (rtnl_mutex){+.+.}-{4:4}, at: switchdev_deferred_process_work+0xe/0x20
4 locks held by syz-executor/6397:
1 lock held by syz.7.508/9878:
 #0: ffff88801f38c0e0 (&type->s_umount_key#70){++++}-{4:4}, at: super_lock+0x2a9/0x3b0
1 lock held by syz.6.684/11259:
 #0: ffff88801f38c0e0 (&type->s_umount_key#70){++++}-{4:4}, at: super_lock+0x2a9/0x3b0
1 lock held by syz.5.804/12089:
 #0: ffff88801f38c0e0 (&type->s_umount_key#70){++++}-{4:4}, at: super_lock+0x2a9/0x3b0
1 lock held by syz.5.804/12090:
 #0: ffff88801f38c0e0 (&type->s_umount_key#70){++++}-{4:4}, at: super_lock+0x2a9/0x3b0
1 lock held by syz.5.804/12091:
 #0: ffff88801f38c0e0 (&type->s_umount_key#70){++++}-{4:4}, at: super_lock+0x2a9/0x3b0
1 lock held by syz.5.804/12092:
 #0: ffff88801f38c0e0 (&type->s_umount_key#70){++++}-{4:4}, at: super_lock+0x2a9/0x3b0
1 lock held by syz.7.871/12418:
 #0: ffff88801f38c0e0 (&type->s_umount_key#70){++++}-{4:4}, at: super_lock+0x2a9/0x3b0
1 lock held by syz-executor/13004:
 #0: ffffffff8f538888 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x3b0/0x18b0

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

NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 34 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+0x189/0x250
 nmi_cpu_backtrace+0x39e/0x3d0
 nmi_trigger_cpumask_backtrace+0x17a/0x300
 watchdog+0xf93/0xfe0
 kthread+0x711/0x8a0
 ret_from_fork+0x3fc/0x770
 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: 5882 Comm: kworker/u8:4 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
Workqueue: bat_events batadv_nc_worker
RIP: 0010:lockdep_softirqs_on+0x1a/0x1c0
Code: 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 66 0f 1f 00 41 57 41 56 53 48 83 ec 10 65 48 8b 05 0b 0a 03 11 48 89 44 24 08 <65> 48 8b 1c 25 08 50 a0 92 83 3d 36 75 06 0e 00 0f 84 1d 01 00 00
RSP: 0018:ffffc9000381f8b0 EFLAGS: 00000082
RAX: 8c11727eab391b00 RBX: 0000000000000201 RCX: 8c11727eab391b00
RDX: 0000000000000000 RSI: ffffffff8be33660 RDI: ffffffff8b479d38
RBP: ffffc9000381f978 R08: ffffffff8fa38a37 R09: 1ffffffff1f47146
R10: dffffc0000000000 R11: fffffbfff1f47147 R12: ffffffff8b479d38
R13: dffffc0000000000 R14: dffffc0000000000 R15: 1ffff92000703f1c
FS:  0000000000000000(0000) GS:ffff8881a3c1b000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f6ce38ff000 CR3: 000000010e0ea000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 __local_bh_enable_ip+0xe9/0x1c0
 batadv_nc_purge_paths+0x318/0x3b0
 batadv_nc_worker+0x328/0x610
 process_scheduled_works+0xae1/0x17b0
 worker_thread+0x8a0/0xda0
 kthread+0x711/0x8a0
 ret_from_fork+0x3fc/0x770
 ret_from_fork_asm+0x1a/0x30
 </TASK>
