syzbot

sp0: Synchronizing with TNC
ODEBUG: free active (active state 0) object type: timer_list hint: resync_tnc+0x0/0x3c0 drivers/net/hamradio/6pack.c:839
------------[ cut here ]------------
WARNING: CPU: 1 PID: 7970 at lib/debugobjects.c:287 debug_print_object.cold+0xa7/0xdb lib/debugobjects.c:287
Kernel panic - not syncing: panic_on_warn set ...

CPU: 1 PID: 7970 Comm: syz-executor412 Not tainted 4.14.277-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0x1b2/0x281 lib/dump_stack.c:58
 panic+0x1f9/0x42d kernel/panic.c:183
 __warn.cold+0x20/0x44 kernel/panic.c:547
 report_bug+0x208/0x250 lib/bug.c:183
 fixup_bug arch/x86/kernel/traps.c:177 [inline]
 fixup_bug arch/x86/kernel/traps.c:172 [inline]
 do_error_trap+0x195/0x2d0 arch/x86/kernel/traps.c:295
 invalid_op+0x1b/0x40 arch/x86/entry/entry_64.S:964
RIP: 0010:debug_print_object.cold+0xa7/0xdb lib/debugobjects.c:287
RSP: 0018:ffff8880b3a578d0 EFLAGS: 00010082
RAX: 0000000000000057 RBX: 0000000000000003 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff878bc600 RDI: ffffed101674af10
RBP: ffffffff878b78c0 R08: 0000000000000057 R09: 0000000000000000
R10: 0000000000000000 R11: ffff8880b527a0c0 R12: ffffffff83f92780
R13: 0000000000000000 R14: ffff8880b374cd40 R15: ffff8880b53ae5b0
 __debug_check_no_obj_freed lib/debugobjects.c:747 [inline]
 debug_check_no_obj_freed+0x3b7/0x680 lib/debugobjects.c:776
 kfree+0xb9/0x250 mm/slab.c:3814
 kvfree+0x45/0x50 mm/util.c:416
 device_release+0x15f/0x1a0 drivers/base/core.c:848
 kobject_cleanup lib/kobject.c:646 [inline]
 kobject_release lib/kobject.c:675 [inline]
 kref_put include/linux/kref.h:70 [inline]
 kobject_put+0x251/0x550 lib/kobject.c:692
 netdev_run_todo+0x747/0xad0 net/core/dev.c:7969
 sixpack_close+0xd3/0x180 drivers/net/hamradio/6pack.c:688
 tty_ldisc_close+0x8c/0xc0 drivers/tty/tty_ldisc.c:505
 tty_ldisc_kill drivers/tty/tty_ldisc.c:651 [inline]
 tty_ldisc_hangup+0x269/0x6c0 drivers/tty/tty_ldisc.c:769
 __tty_hangup.part.0+0x31a/0x730 drivers/tty/tty_io.c:622
 __tty_hangup drivers/tty/tty_io.c:572 [inline]
 tty_vhangup+0x1d/0x30 drivers/tty/tty_io.c:695
 pty_close+0x35f/0x4b0 drivers/tty/pty.c:79
 tty_release+0x40b/0x10d0 drivers/tty/tty_io.c:1670
 __fput+0x25f/0x7a0 fs/file_table.c:210
 task_work_run+0x11f/0x190 kernel/task_work.c:113
 exit_task_work include/linux/task_work.h:22 [inline]
 do_exit+0xa44/0x2850 kernel/exit.c:868
 do_group_exit+0x100/0x2e0 kernel/exit.c:965
 SYSC_exit_group kernel/exit.c:976 [inline]
 SyS_exit_group+0x19/0x20 kernel/exit.c:974
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x46/0xbb
RIP: 0033:0x7f61f41cb049
RSP: 002b:00007ffcbc66e108 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 00007f61f423f330 RCX: 00007f61f41cb049
RDX: 000000000000003c RSI: 00000000000000e7 RDI: 0000000000000000
RBP: 0000000000000000 R08: ffffffffffffffc0 R09: 000000000000000d
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f61f423f330
R13: 0000000000000001 R14: 0000000000000000 R15: 0000000000000001

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