INFO: task syz.2.2714:16690 blocked for more than 143 seconds.
      Not tainted syzkaller #0
      Blocked by coredump.
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.2.2714      state:D stack:23352 pid:16690 tgid:16689 ppid:16342  task_flags:0x40054c flags:0x00004002
Call Trace:
 <TASK>
 __schedule+0x1798/0x4cc0
 schedule+0x165/0x360
 schedule_preempt_disabled+0x13/0x30
 rwsem_down_write_slowpath+0x872/0xfe0
 down_write+0x1ab/0x1f0
 exit_mmap+0x28e/0xb50
 __mmput+0x118/0x430
 exit_mm+0x1da/0x2c0
 do_exit+0x648/0x2300
 do_group_exit+0x21c/0x2d0
 get_signal+0x1286/0x1340
 arch_do_signal_or_restart+0x9a/0x750
 exit_to_user_mode_loop+0x75/0x110
 do_syscall_64+0x2bd/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f384c38ec29
RSP: 002b:00007f384d17c038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: 0000000000000094 RBX: 00007f384c5d5fa0 RCX: 00007f384c38ec29
RDX: 0000000024000840 RSI: 0000200000009b40 RDI: 0000000000000008
RBP: 00007f384c411e41 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f384c5d6038 R14: 00007f384c5d5fa0 R15: 00007ffdbc5785a8
 </TASK>

Showing all locks held in the system:
3 locks held by kworker/1:0/24:
 #0: ffff88801a482148 ((wq_completion)events_power_efficient){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0
 #1: ffffc900001c7bc0 ((crda_timeout).work){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0
 #2: ffffffff8f53adc8 (rtnl_mutex){+.+.}-{4:4}, at: crda_timeout_work+0x15/0x50
1 lock held by khungtaskd/34:
 #0: ffffffff8e13a160 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180
2 locks held by getty/5676:
 #0: ffff88810689e0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70
 #1: ffffc900029032f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400
3 locks held by syz-executor/5817:
6 locks held by kworker/u8:3/13790:
 #0: ffff88801b2f7148 ((wq_completion)netns){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0
 #1: ffffc90006b87bc0 (net_cleanup_work){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0
 #2: ffffffff8f52df10 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xf7/0x800
 #3: ffff8880320570e8 (&dev->mutex){....}-{4:4}, at: devlink_pernet_pre_exit+0x10a/0x3d0
 #4: ffff888032051250 (&devlink->lock_key#60){+.+.}-{4:4}, at: devlink_pernet_pre_exit+0x11c/0x3d0
 #5: ffffffff8f53adc8 (rtnl_mutex){+.+.}-{4:4}, at: unregister_nexthop_notifier+0x17/0x40
1 lock held by syz.2.2714/16690:
 #0: ffff88801a47ed60 (&mm->mmap_lock){++++}-{4:4}, at: exit_mmap+0x28e/0xb50
3 locks held by syz-executor/18063:
 #0: ffffffff8ecaa3e0 (&ops->srcu#2){.+.+}-{0:0}, at: rtnl_link_ops_get+0x23/0x250
 #1: ffffffff8f53adc8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x8db/0x1c70
 #2: ffffffff8e13fbf8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x2f6/0x730
1 lock held by syz-executor/18078:
 #0: ffffffff8f53adc8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x8db/0x1c70

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

NMI backtrace for cpu 1
CPU: 1 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+0x439/0x7d0
 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: 12 Comm: kworker/u8:0 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:__this_cpu_preempt_check+0x4/0x20
Code: eb a7 e8 8f e4 ff ff 66 66 66 66 66 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa <48> 89 fe 48 c7 c7 80 44 e3 8b e9 bd fe ff ff cc cc cc cc cc cc cc
RSP: 0018:ffffc900000f7978 EFLAGS: 00000092
RAX: 0000000000000001 RBX: 0000000000000000 RCX: 051f88b6c710f500
RDX: 0000000000000000 RSI: ffff88801c2f6180 RDI: ffffffff8dbaa5a5
RBP: ffffffff8b489962 R08: 0000000000000000 R09: ffffffff8b489962
R10: ffffc900000f77e0 R11: ffffffffa0000910 R12: 0000000000000002
R13: ffffffff8e13a160 R14: 0000000000000000 R15: 0000000000000246
FS:  0000000000000000(0000) GS:ffff8880b8611000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ff227c87e20 CR3: 000000010ed4c000 CR4: 00000000000006f0
DR0: 0000200000000300 DR1: 0000000000000082 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <TASK>
 lock_acquire+0x130/0x360
 batadv_nc_worker+0xef/0x610
 process_scheduled_works+0xae1/0x17b0
 worker_thread+0x8a0/0xda0
 kthread+0x711/0x8a0
 ret_from_fork+0x439/0x7d0
 ret_from_fork_asm+0x1a/0x30
 </TASK>
