[ OK ] Started Getty on tty2. Starting Load/Save RF Kill Switch Status... [ OK ] Started Getty on tty1. [ OK ] Started Serial Getty on ttyS0. [ 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 Load/Save RF Kill Switch Status. [ OK ] Started Update UTMP about System Runlevel Changes. Debian GNU/Linux 9 syzkaller ttyS0 Warning: Permanently added '10.128.0.104' (ECDSA) to the list of known hosts. executing program executing program executing program executing program executing program executing program syzkaller login: [ 58.245972][ T6833] 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 [ 58.833929][ T21] ------------[ cut here ]------------ [ 58.839615][ T21] refcount_t: addition on 0; use-after-free. [ 58.845856][ T21] WARNING: CPU: 0 PID: 21 at lib/refcount.c:25 refcount_warn_saturate+0x169/0x1e0 [ 58.855088][ T21] Kernel panic - not syncing: panic_on_warn set ... [ 58.861803][ T21] CPU: 0 PID: 21 Comm: kworker/u4:1 Not tainted 5.9.0-rc3-syzkaller #0 [ 58.870026][ T21] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 58.880433][ T21] Workqueue: qrtr_ns_handler qrtr_ns_worker [ 58.886300][ T21] Call Trace: [ 58.889571][ T21] dump_stack+0x198/0x1fd [ 58.893968][ T21] panic+0x347/0x7c0 [ 58.897843][ T21] ? __warn_printk+0xf3/0xf3 [ 58.902427][ T21] ? _raw_spin_unlock+0x24/0x40 [ 58.907270][ T21] ? __printk_safe_exit+0x5/0x10 [ 58.912182][ T21] ? console_unlock+0x733/0xe60 [ 58.917009][ T21] ? __warn.cold+0x5/0x46 [ 58.921327][ T21] ? __warn+0xd6/0x1f2 [ 58.925390][ T21] ? refcount_warn_saturate+0x169/0x1e0 [ 58.931062][ T21] __warn.cold+0x20/0x46 [ 58.935302][ T21] ? wake_up_klogd.part.0+0x8c/0xc0 [ 58.940528][ T21] ? refcount_warn_saturate+0x169/0x1e0 [ 58.946072][ T21] report_bug+0x1bd/0x210 [ 58.950397][ T21] handle_bug+0x38/0x90 [ 58.954594][ T21] exc_invalid_op+0x14/0x40 [ 58.959078][ T21] asm_exc_invalid_op+0x12/0x20 [ 58.964038][ T21] RIP: 0010:refcount_warn_saturate+0x169/0x1e0 [ 58.970222][ T21] Code: 07 31 ff 89 de e8 e7 df d8 fd 84 db 0f 85 36 ff ff ff e8 9a e3 d8 fd 48 c7 c7 00 dc 93 88 c6 05 67 18 12 07 01 e8 09 e7 a9 fd <0f> 0b e9 17 ff ff ff e8 7b e3 d8 fd 0f b6 1d 4c 18 12 07 31 ff 89 [ 58.990001][ T21] RSP: 0018:ffffc90000dd79d8 EFLAGS: 00010086 [ 58.996048][ T21] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 [ 59.006003][ T21] RDX: ffff8880a902c580 RSI: ffffffff815db9a7 RDI: fffff520001baf2d [ 59.014054][ T21] RBP: 0000000000000002 R08: 0000000000000001 R09: ffff8880ae620f8b [ 59.022019][ T21] R10: 0000000000000000 R11: 0000000000003254 R12: ffff88821b0f6040 [ 59.029986][ T21] R13: ffff888093a6cc00 R14: ffff88809da20230 R15: ffff88809da20234 [ 59.037955][ T21] ? vprintk_func+0x97/0x1a6 [ 59.042564][ T21] ? refcount_warn_saturate+0x169/0x1e0 [ 59.048103][ T21] qrtr_recvmsg+0x845/0x970 [ 59.052606][ T21] ? qrtr_node_enqueue+0x1240/0x1240 [ 59.057890][ T21] ? lock_is_held_type+0xbb/0xf0 [ 59.062862][ T21] ? bpf_lsm_socket_recvmsg+0x5/0x10 [ 59.068137][ T21] ? security_socket_recvmsg+0x8f/0xc0 [ 59.073606][ T21] ? qrtr_node_enqueue+0x1240/0x1240 [ 59.078974][ T21] kernel_recvmsg+0x110/0x160 [ 59.083632][ T21] qrtr_ns_worker+0x15a/0x14fc [ 59.088378][ T21] ? lockdep_hardirqs_on_prepare+0x530/0x530 [ 59.094351][ T21] ? ctrl_cmd_del_client+0x730/0x730 [ 59.099624][ T21] ? lock_acquire+0x1f3/0xae0 [ 59.104278][ T21] ? process_one_work+0x85f/0x1670 [ 59.109374][ T21] ? _raw_spin_unlock_irq+0x1f/0x80 [ 59.114652][ T21] ? lock_is_held_type+0xbb/0xf0 [ 59.119570][ T21] process_one_work+0x94c/0x1670 [ 59.124504][ T21] ? lock_release+0x8f0/0x8f0 [ 59.129155][ T21] ? pwq_dec_nr_in_flight+0x2d0/0x2d0 [ 59.134527][ T21] ? rwlock_bug.part.0+0x90/0x90 [ 59.139456][ T21] ? lockdep_hardirqs_off+0x96/0xd0 [ 59.144635][ T21] worker_thread+0x64c/0x1120 [ 59.149383][ T21] ? process_one_work+0x1670/0x1670 [ 59.154554][ T21] kthread+0x3b5/0x4a0 [ 59.158600][ T21] ? __kthread_bind_mask+0xc0/0xc0 [ 59.163708][ T21] ret_from_fork+0x1f/0x30 [ 60.227952][ T21] Shutting down cpus with NMI [ 60.234169][ T21] Kernel Offset: disabled [ 60.238544][ T21] Rebooting in 86400 seconds..