[ OK ] Started Getty on tty4. [ OK ] Started Getty on tty3. [ OK ] Started Getty on tty2. [ OK ] Started Serial Getty on ttyS0. [ OK ] Started Getty on tty1. [ OK ] Reached target Login Prompts. [ OK ] Reached target Multi-User System. [ OK ] Reached target Graphical Interface. Starting Update UTMP about System Runlevel Changes... [ OK ] Started Update UTMP about System Runlevel Changes. Starting Load/Save RF Kill Switch Status... [ OK ] Started Load/Save RF Kill Switch Status. Debian GNU/Linux 9 syzkaller ttyS0 Warning: Permanently added '10.128.1.17' (ECDSA) to the list of known hosts. syzkaller login: [ 55.168524][ T6823] IPVS: ftp: loaded support on port[0] = 21 [ 55.178693][ T6818] IPVS: ftp: loaded support on port[0] = 21 [ 55.182927][ T6825] IPVS: ftp: loaded support on port[0] = 21 [ 55.189886][ T6822] IPVS: ftp: loaded support on port[0] = 21 [ 55.205042][ T6824] IPVS: ftp: loaded support on port[0] = 21 [ 55.214364][ T6826] IPVS: ftp: loaded support on port[0] = 21 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 58.417755][ T6975] ------------[ cut here ]------------ [ 58.424030][ T6975] refcount_t: addition on 0; use-after-free. [ 58.430332][ T6975] WARNING: CPU: 0 PID: 6975 at lib/refcount.c:25 refcount_warn_saturate+0x169/0x1e0 [ 58.439681][ T6975] Kernel panic - not syncing: panic_on_warn set ... [ 58.446245][ T6975] CPU: 0 PID: 6975 Comm: kworker/u5:4 Not tainted 5.8.0-syzkaller #0 [ 58.454279][ T6975] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 58.464315][ T6975] Workqueue: hci5 hci_rx_work [ 58.468967][ T6975] Call Trace: [ 58.472257][ T6975] dump_stack+0x18f/0x20d [ 58.476569][ T6975] panic+0x2e3/0x75c [ 58.480443][ T6975] ? __warn_printk+0xf3/0xf3 [ 58.485024][ T6975] ? lockdep_hardirqs_on+0x76/0xf0 [ 58.490114][ T6975] ? __warn.cold+0x5/0x45 [ 58.494418][ T6975] ? __warn+0xd6/0x1f2 [ 58.498465][ T6975] ? refcount_warn_saturate+0x169/0x1e0 [ 58.503987][ T6975] __warn.cold+0x20/0x45 [ 58.508204][ T6975] ? wake_up_klogd.part.0+0x8c/0xc0 [ 58.513376][ T6975] ? refcount_warn_saturate+0x169/0x1e0 [ 58.518898][ T6975] report_bug+0x1bd/0x210 [ 58.523217][ T6975] handle_bug+0x38/0x90 [ 58.527369][ T6975] exc_invalid_op+0x14/0x40 [ 58.531862][ T6975] asm_exc_invalid_op+0x12/0x20 [ 58.536691][ T6975] RIP: 0010:refcount_warn_saturate+0x169/0x1e0 [ 58.542821][ T6975] Code: 07 31 ff 89 de e8 37 7a db fd 84 db 0f 85 36 ff ff ff e8 ea 7d db fd 48 c7 c7 e0 8d 93 88 c6 05 9c bc 13 07 01 e8 29 8d ac fd <0f> 0b e9 17 ff ff ff e8 cb 7d db fd 0f b6 1d 81 bc 13 07 31 ff 89 [ 58.562400][ T6975] RSP: 0018:ffffc900064b7908 EFLAGS: 00010286 [ 58.568445][ T6975] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 [ 58.576439][ T6975] RDX: ffff888095e2c240 RSI: ffffffff815db477 RDI: fffff52000c96f13 [ 58.584387][ T6975] RBP: 0000000000000002 R08: 0000000000000001 R09: ffff8880ae631927 [ 58.592336][ T6975] R10: 0000000000000000 R11: 0000000037393654 R12: dffffc0000000000 [ 58.600283][ T6975] R13: 0000000000000001 R14: ffff8880a2a79000 R15: 0000000000000003 [ 58.608258][ T6975] ? vprintk_func+0x97/0x1a6 [ 58.612830][ T6975] ? refcount_warn_saturate+0x169/0x1e0 [ 58.618363][ T6975] l2cap_global_chan_by_psm+0x53f/0x5b0 [ 58.623896][ T6975] ? l2cap_chan_timeout+0x450/0x450 [ 58.629072][ T6975] ? lockdep_hardirqs_on_prepare+0x530/0x530 [ 58.635039][ T6975] ? mark_lock+0xbc/0x1710 [ 58.639952][ T6975] ? __lock_acquire+0x16cb/0x5640 [ 58.644955][ T6975] l2cap_recv_frame+0xc3b/0xae10 [ 58.649877][ T6975] ? hci_rx_work+0x35b/0xb50 [ 58.654452][ T6975] ? __lock_acquire+0xbb5/0x5640 [ 58.661377][ T6975] ? l2cap_config_rsp.isra.0+0x1130/0x1130 [ 58.667157][ T6975] ? find_held_lock+0x2d/0x110 [ 58.671914][ T6975] ? hci_rx_work+0x498/0xb50 [ 58.676976][ T6975] ? lock_downgrade+0x830/0x830 [ 58.681811][ T6975] ? lock_acquire+0x1f1/0xad0 [ 58.686494][ T6975] ? hci_rx_work+0x33d/0xb50 [ 58.691066][ T6975] ? find_held_lock+0x2d/0x110 [ 58.695814][ T6975] ? __mutex_unlock_slowpath+0xe2/0x610 [ 58.701336][ T6975] ? hci_conn_enter_active_mode+0x11a/0x2e0 [ 58.707212][ T6975] l2cap_recv_acldata+0x7f6/0x8e0 [ 58.712215][ T6975] hci_rx_work+0x4c7/0xb50 [ 58.716612][ T6975] process_one_work+0x94c/0x1670 [ 58.721532][ T6975] ? lock_release+0x8e0/0x8e0 [ 58.726185][ T6975] ? pwq_dec_nr_in_flight+0x2d0/0x2d0 [ 58.731533][ T6975] ? rwlock_bug.part.0+0x90/0x90 [ 58.736454][ T6975] worker_thread+0x64c/0x1120 [ 58.741113][ T6975] ? __kthread_parkme+0x13f/0x1e0 [ 58.746113][ T6975] ? process_one_work+0x1670/0x1670 [ 58.751286][ T6975] kthread+0x3b5/0x4a0 [ 58.755336][ T6975] ? __kthread_bind_mask+0xc0/0xc0 [ 58.760420][ T6975] ? __kthread_bind_mask+0xc0/0xc0 [ 58.765511][ T6975] ret_from_fork+0x1f/0x30 [ 58.771261][ T6975] Kernel Offset: disabled [ 58.775636][ T6975] Rebooting in 86400 seconds..