------------[ cut here ]------------
refcount_t: underflow; use-after-free.
WARNING: CPU: 1 PID: 2801 at lib/refcount.c:28 refcount_warn_saturate+0x165/0x1b0 lib/refcount.c:28
Kernel panic - not syncing: panic_on_warn set ...
CPU: 1 PID: 2801 Comm: kworker/1:12 Not tainted 5.6.0-rc3-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: events do_enable_set
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x1fb/0x318 lib/dump_stack.c:118
 panic+0x264/0x7a9 kernel/panic.c:221
 __warn+0x209/0x210 kernel/panic.c:582
 report_bug+0x1b6/0x2f0 lib/bug.c:195
 fixup_bug arch/x86/kernel/traps.c:174 [inline]
 do_error_trap+0xcf/0x1c0 arch/x86/kernel/traps.c:267
 do_invalid_op+0x36/0x40 arch/x86/kernel/traps.c:286
 invalid_op+0x23/0x30 arch/x86/entry/entry_64.S:1027
RIP: 0010:refcount_warn_saturate+0x165/0x1b0 lib/refcount.c:28
Code: c7 24 e3 f0 88 31 c0 e8 b9 2d a8 fd 0f 0b eb 83 e8 f0 67 d6 fd c6 05 aa 31 c5 05 01 48 c7 c7 50 e3 f0 88 31 c0 e8 9b 2d a8 fd <0f> 0b e9 62 ff ff ff e8 cf 67 d6 fd c6 05 8a 31 c5 05 01 48 c7 c7
RSP: 0018:ffffc9000871fbf0 EFLAGS: 00010246
RAX: 25994bc5ee083f00 RBX: 0000000000000003 RCX: ffff88809f34a440
RDX: 0000000000000000 RSI: 0000000080000000 RDI: 0000000000000000
RBP: ffffc9000871fc00 R08: ffffffff81600324 R09: ffffed1015d66618
R10: ffffed1015d66618 R11: 0000000000000000 R12: ffff8880a6985018
R13: dffffc0000000000 R14: 0000000000000003 R15: ffff88809f2e9280
 refcount_sub_and_test include/linux/refcount.h:261 [inline]
 refcount_dec_and_test include/linux/refcount.h:281 [inline]
 kref_put include/linux/kref.h:64 [inline]
 l2cap_chan_put+0x18d/0x190 net/bluetooth/l2cap_core.c:498
 do_enable_set+0x66c/0x900 net/bluetooth/6lowpan.c:1075
 process_one_work+0x7f5/0x10f0 kernel/workqueue.c:2264
 worker_thread+0xbbc/0x1630 kernel/workqueue.c:2410
 kthread+0x332/0x350 kernel/kthread.c:255
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352
Kernel Offset: disabled
Rebooting in 86400 seconds..