ODEBUG: free active (active state 0) object type: timer_list hint: delayed_work_timer_fn+0x0/0x90 kernel/workqueue.c:4850
------------[ cut here ]------------
WARNING: CPU: 0 PID: 7492 at lib/debugobjects.c:287 debug_print_object.cold+0xa7/0xdb lib/debugobjects.c:287
Kernel panic - not syncing: panic_on_warn set ...

CPU: 0 PID: 7492 Comm: kworker/u4:2 Not tainted 4.14.161-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: netns cleanup_net
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0x142/0x197 lib/dump_stack.c:58
 panic+0x1f9/0x42d kernel/panic.c:183
 __warn.cold+0x2f/0x2f kernel/panic.c:547
 report_bug+0x216/0x254 lib/bug.c:186
 fixup_bug arch/x86/kernel/traps.c:177 [inline]
 fixup_bug arch/x86/kernel/traps.c:172 [inline]
 do_error_trap+0x1bb/0x310 arch/x86/kernel/traps.c:295
 do_invalid_op+0x1b/0x20 arch/x86/kernel/traps.c:314
 invalid_op+0x1b/0x40 arch/x86/entry/entry_64.S:963
RIP: 0010:debug_print_object.cold+0xa7/0xdb lib/debugobjects.c:287
RSP: 0018:ffff888090bd7860 EFLAGS: 00010082
RAX: 0000000000000061 RBX: 0000000000000003 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff87040e40 RDI: ffffed101217af02
RBP: ffff888090bd7888 R08: 0000000000000061 R09: 0000000000000000
R10: 0000000000000000 R11: ffff88806e44a380 R12: ffffffff86cbf760
R13: ffffffff813d9630 R14: 0000000000000000 R15: ffff888070186240
 __debug_check_no_obj_freed lib/debugobjects.c:747 [inline]
 debug_check_no_obj_freed+0x3f5/0x7b7 lib/debugobjects.c:776
 kfree+0xbd/0x270 mm/slab.c:3814
 kvfree+0x4d/0x60 mm/util.c:416
 netdev_freemem+0x4c/0x60 net/core/dev.c:8039
 netdev_release+0x72/0x90 net/core/net-sysfs.c:1497
 device_release+0x163/0x1a0 drivers/base/core.c:825
 kobject_cleanup lib/kobject.c:646 [inline]
 kobject_release lib/kobject.c:675 [inline]
 kref_put include/linux/kref.h:70 [inline]
 kobject_put.cold+0x269/0x2f9 lib/kobject.c:692
 netdev_run_todo+0x4e4/0x770 net/core/dev.c:7944
 rtnl_unlock+0xe/0x10 net/core/rtnetlink.c:106
 default_device_exit_batch+0x328/0x3d0 net/core/dev.c:8730
 ops_exit_list.isra.0+0xfc/0x150 net/core/net_namespace.c:145
 cleanup_net+0x3ba/0x870 net/core/net_namespace.c:484
 process_one_work+0x863/0x1600 kernel/workqueue.c:2114
 worker_thread+0x5d9/0x1050 kernel/workqueue.c:2248
 kthread+0x319/0x430 kernel/kthread.c:232
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404

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