Re: WARNING: ODEBUG bug in netdev_freemem (2)

[syzbot]

syzbot has found a reproducer for the following crash on:

HEAD commit:    13dfb3fa Merge git://git.kernel.org/pub/scm/linux/kernel/g..
git tree:       net-next
console output: https://syzkaller.appspot.com/x/log.txt?x=1671e69a600000
kernel config:  https://syzkaller.appspot.com/x/.config?x=d4cf1ffb87d590d7
dashboard link: https://syzkaller.appspot.com/bug?extid=c4521ac872a4ccc3afec
compiler:       gcc (GCC) 9.0.0 20181231 (experimental)
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=170542c2600000

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

bond0 (unregistering): (slave bond_slave_1): Releasing backup interface
bond0 (unregistering): (slave bond_slave_0): Releasing backup interface
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:768
WARNING: CPU: 0 PID: 9919 at lib/debugobjects.c:481  
debug_print_object+0x168/0x250 lib/debugobjects.c:481
Kernel panic - not syncing: panic_on_warn set ...
CPU: 0 PID: 9919 Comm: kworker/u4:6 Not tainted 5.3.0-rc3+ #122
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+0x2dc/0x755 kernel/panic.c:219
 __warn.cold+0x20/0x4c 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+0x23/0x30 arch/x86/entry/entry_64.S:1028
RIP: 0010:debug_print_object+0x168/0x250 lib/debugobjects.c:481
Code: dd e0 32 c6 87 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 b5 00 00 00 48  
8b 14 dd e0 32 c6 87 48 c7 c7 e0 27 c6 87 e8 70 cd 05 fe <0f> 0b 83 05 a3  
7c 67 06 01 48 83 c4 20 5b 41 5c 41 5d 41 5e 5d c3
RSP: 0018:ffff8880898ff838 EFLAGS: 00010086
RAX: 0000000000000000 RBX: 0000000000000003 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff815c3ba6 RDI: ffffed101131fef9
RBP: ffff8880898ff878 R08: ffff88808ece42c0 R09: ffffed1015d04101
R10: ffffed1015d04100 R11: ffff8880ae820807 R12: 0000000000000001
R13: ffffffff88db6660 R14: ffffffff8161da40 R15: ffff88808f639af0
 __debug_check_no_obj_freed lib/debugobjects.c:963 [inline]
 debug_check_no_obj_freed+0x2d4/0x43f lib/debugobjects.c:994
 kfree+0xf8/0x2c0 mm/slab.c:3755
 kvfree+0x61/0x70 mm/util.c:488
 netdev_freemem+0x4c/0x60 net/core/dev.c:9093
 netdev_release+0x86/0xb0 net/core/net-sysfs.c:1635
 device_release+0x7a/0x210 drivers/base/core.c:1064
 kobject_cleanup lib/kobject.c:693 [inline]
 kobject_release lib/kobject.c:722 [inline]
 kref_put include/linux/kref.h:65 [inline]
 kobject_put.cold+0x289/0x2e6 lib/kobject.c:739
 netdev_run_todo+0x53b/0x7b0 net/core/dev.c:8998
 rtnl_unlock+0xe/0x10 net/core/rtnetlink.c:112
 default_device_exit_batch+0x358/0x410 net/core/dev.c:9781
 ops_exit_list.isra.0+0xfc/0x150 net/core/net_namespace.c:175
 cleanup_net+0x4e2/0xa70 net/core/net_namespace.c:594
 process_one_work+0x9af/0x1740 kernel/workqueue.c:2269
 worker_thread+0x98/0xe40 kernel/workqueue.c:2415
 kthread+0x361/0x430 kernel/kthread.c:255
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352
Kernel Offset: disabled
Rebooting in 86400 seconds..