------------[ cut here ]------------ refcount_t: addition on 0; use-after-free. WARNING: CPU: 0 PID: 6872 at lib/refcount.c:25 refcount_warn_saturate+0x13d/0x1a0 lib/refcount.c:25 Kernel panic - not syncing: panic_on_warn set ... CPU: 0 PID: 6872 Comm: kworker/u5:1 Not tainted 5.8.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: hci0 hci_rx_work Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1f0/0x31e lib/dump_stack.c:118 panic+0x264/0x7a0 kernel/panic.c:231 __warn+0x227/0x250 kernel/panic.c:600 report_bug+0x1b1/0x2e0 lib/bug.c:198 handle_bug+0x42/0x80 arch/x86/kernel/traps.c:235 exc_invalid_op+0x16/0x40 arch/x86/kernel/traps.c:255 asm_exc_invalid_op+0x12/0x20 arch/x86/include/asm/idtentry.h:547 RIP: 0010:refcount_warn_saturate+0x13d/0x1a0 lib/refcount.c:25 Code: c7 63 cd f4 88 31 c0 e8 71 98 a9 fd 0f 0b eb a3 e8 d8 e8 d7 fd c6 05 b7 7f cc 05 01 48 c7 c7 9a cd f4 88 31 c0 e8 53 98 a9 fd <0f> 0b eb 85 e8 ba e8 d7 fd c6 05 9a 7f cc 05 01 48 c7 c7 c6 cd f4 RSP: 0018:ffffc900048e7a70 EFLAGS: 00010246 RAX: 17b089bd6e699700 RBX: 0000000000000002 RCX: ffff888091430000 RDX: 0000000000000000 RSI: 0000000080000001 RDI: 0000000000000000 RBP: 0000000000000002 R08: ffffffff815dffc9 R09: ffffed1015d062c0 R10: ffffed1015d062c0 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: ffff8880a901a018 R15: 0000000000000001 refcount_add include/linux/refcount.h:206 [inline] refcount_inc include/linux/refcount.h:241 [inline] kref_get include/linux/kref.h:45 [inline] l2cap_chan_hold net/bluetooth/l2cap_core.c:495 [inline] l2cap_global_chan_by_psm+0x4aa/0x4e0 net/bluetooth/l2cap_core.c:1978 l2cap_conless_channel net/bluetooth/l2cap_core.c:7596 [inline] l2cap_recv_frame+0x530/0x8f10 net/bluetooth/l2cap_core.c:7666 hci_acldata_packet net/bluetooth/hci_core.c:4520 [inline] hci_rx_work+0x7d7/0x9c0 net/bluetooth/hci_core.c:4710 process_one_work+0x789/0xfc0 kernel/workqueue.c:2269 worker_thread+0xaa4/0x1460 kernel/workqueue.c:2415 kthread+0x37e/0x3a0 drivers/block/aoe/aoecmd.c:1234 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:293 Kernel Offset: disabled Rebooting in 86400 seconds..