------------[ cut here ]------------
ODEBUG: free active (active state 0) object type: timer_list hint: delayed_work_timer_fn+0x0/0x90 kernel/workqueue.c:1601
WARNING: CPU: 1 PID: 49 at lib/debugobjects.c:505 debug_print_object+0x16e/0x250 lib/debugobjects.c:505
Modules linked in:
CPU: 1 PID: 49 Comm: kworker/u4:2 Not tainted 5.11.0-rc7-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: netns cleanup_net

RIP: 0010:debug_print_object+0x16e/0x250 lib/debugobjects.c:505
Code: ff df 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 af 00 00 00 48 8b 14 dd e0 d3 dd 88 4c 89 ee 48 c7 c7 e0 c7 dd 88 e8 5f b9 80 04 <0f> 0b 83 05 f5 5b bc 08 01 48 83 c4 18 5b 5d 41 5c 41 5d 41 5e c3
RSP: 0018:ffffc90000eff890 EFLAGS: 00010282

RAX: 0000000000000000 RBX: 0000000000000003 RCX: 0000000000000000
RDX: 0000000000000001 RSI: ffffffff88ddc3c0 RDI: fffff520001dff04
RBP: 0000000000000001 R08: 0000000000000001 R09: ffff8880b9f30827
R10: ffffed10173e6104 R11: 657461747320654f R12: ffffffff888cd2e0
R13: ffffffff88ddce20 R14: ffffffff81594740 R15: dffffc0000000000
FS:  0000000000000000(0000) GS:ffff8880b9f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000004b1290 CR3: 0000000013ac0000 CR4: 00000000001506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 __debug_check_no_obj_freed lib/debugobjects.c:987 [inline]
 debug_check_no_obj_freed+0x301/0x420 lib/debugobjects.c:1018
 slab_free_hook mm/slub.c:1539 [inline]
 slab_free_freelist_hook+0x107/0x150 mm/slub.c:1580
 slab_free mm/slub.c:3143 [inline]
 kfree+0xdb/0x3b0 mm/slub.c:4139
 device_release+0x93/0x200 drivers/base/core.c:1980
 kobject_cleanup lib/kobject.c:705 [inline]
 kobject_release lib/kobject.c:736 [inline]
 kref_put include/linux/kref.h:65 [inline]
 kobject_put+0x139/0x410 lib/kobject.c:753
 netdev_run_todo+0x810/0xcd0 net/core/dev.c:10491
 default_device_exit_batch+0x2aa/0x360 net/core/dev.c:11442
 cleanup_net+0x423/0x990 net/core/net_namespace.c:595
 process_one_work+0x84c/0x13b0 kernel/workqueue.c:2275
 worker_thread+0x598/0xf80 kernel/workqueue.c:2421
 kthread+0x36f/0x450 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296