WARNING: ODEBUG bug in netdev_freemem (2)

[syzbot <syzbot+c4521ac872a4ccc3afec@syzkaller.appspotmail.com>]

Hello,

syzbot found the following crash on:

HEAD commit:    fd6b99fa Merge branch 'akpm' (patches from Andrew)
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=144de256a00000
kernel config:  https://syzkaller.appspot.com/x/.config?x=fa9f7e1b6a8bb586
dashboard link: https://syzkaller.appspot.com/bug?extid=c4521ac872a4ccc3afec
compiler:       gcc (GCC) 9.0.0 20181231 (experimental)

Unfortunately, I don't have any reproducer for this crash yet.

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+c4521ac872a4ccc3afec@syzkaller.appspotmail.com

device hsr_slave_0 left promiscuous mode
team0 (unregistering): Port device team_slave_1 removed
team0 (unregistering): Port device team_slave_0 removed
bond0 (unregistering): Releasing backup interface bond_slave_1
bond0 (unregistering): Releasing backup interface bond_slave_0
bond0 (unregistering): Released all slaves
------------[ cut here ]------------
ODEBUG: free active (active state 0) object type: timer_list hint:  
delayed_work_timer_fn+0x0/0x90 arch/x86/include/asm/paravirt.h:767
WARNING: CPU: 1 PID: 25149 at lib/debugobjects.c:325  
debug_print_object+0x168/0x250 lib/debugobjects.c:325
Kernel panic - not syncing: panic_on_warn set ...
CPU: 1 PID: 25149 Comm: kworker/u4:1 Not tainted 5.2.0-rc4+ #31
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:77 [inline]
  dump_stack+0x172/0x1f0 lib/dump_stack.c:113
  panic+0x2cb/0x744 kernel/panic.c:219
  __warn.cold+0x20/0x4d kernel/panic.c:576
  report_bug+0x263/0x2b0 lib/bug.c:186
  fixup_bug arch/x86/kernel/traps.c:179 [inline]
  fixup_bug arch/x86/kernel/traps.c:174 [inline]
  do_error_trap+0x11b/0x200 arch/x86/kernel/traps.c:272
  do_invalid_op+0x37/0x50 arch/x86/kernel/traps.c:291
  invalid_op+0x14/0x20 arch/x86/entry/entry_64.S:986
RIP: 0010:debug_print_object+0x168/0x250 lib/debugobjects.c:325
Code: dd e0 c9 a4 87 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 b5 00 00 00 48  
8b 14 dd e0 c9 a4 87 48 c7 c7 80 bf a4 87 e8 16 75 0d fe <0f> 0b 83 05 4b  
46 4b 06 01 48 83 c4 20 5b 41 5c 41 5d 41 5e 5d c3
RSP: 0018:ffff888058c07838 EFLAGS: 00010086
RAX: 0000000000000000 RBX: 0000000000000003 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff815ac956 RDI: ffffed100b180ef9
RBP: ffff888058c07878 R08: ffff88805692a340 R09: ffffed1015d240f1
R10: ffffed1015d240f0 R11: ffff8880ae920787 R12: 0000000000000001
R13: ffffffff88bad1a0 R14: ffffffff816039d0 R15: ffff88805f992e60
  __debug_check_no_obj_freed lib/debugobjects.c:785 [inline]
  debug_check_no_obj_freed+0x29f/0x464 lib/debugobjects.c:817
  kfree+0xbd/0x220 mm/slab.c:3754
  kvfree+0x61/0x70 mm/util.c:460
  netdev_freemem+0x4c/0x60 net/core/dev.c:9070
  netdev_release+0x86/0xb0 net/core/net-sysfs.c:1635
  device_release+0x7a/0x210 drivers/base/core.c:1064
  kobject_cleanup lib/kobject.c:691 [inline]
  kobject_release lib/kobject.c:720 [inline]
  kref_put include/linux/kref.h:65 [inline]
  kobject_put.cold+0x289/0x2e6 lib/kobject.c:737
  netdev_run_todo+0x53b/0x7c0 net/core/dev.c:8975
  rtnl_unlock+0xe/0x10 net/core/rtnetlink.c:112
  default_device_exit_batch+0x358/0x410 net/core/dev.c:9756
  ops_exit_list.isra.0+0xfc/0x150 net/core/net_namespace.c:157
  cleanup_net+0x3fb/0x960 net/core/net_namespace.c:553
  process_one_work+0x989/0x1790 kernel/workqueue.c:2269
  worker_thread+0x98/0xe40 kernel/workqueue.c:2415
  kthread+0x354/0x420 kernel/kthread.c:255
  ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352

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