[ 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. Debian GNU/Linux 9 syzkaller ttyS0 Warning: Permanently added '10.128.0.177' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 57.240458][ T6889] IPVS: ftp: loaded support on port[0] = 21 [ 57.279062][ T6680] ------------[ cut here ]------------ [ 57.284630][ T6680] refcount_t: addition on 0; use-after-free. [ 57.290845][ T6680] WARNING: CPU: 0 PID: 6680 at lib/refcount.c:25 refcount_warn_saturate+0x169/0x1e0 [ 57.300200][ T6680] Kernel panic - not syncing: panic_on_warn set ... [ 57.306764][ T6680] CPU: 0 PID: 6680 Comm: kworker/u4:6 Not tainted 5.9.0-rc6-syzkaller #0 [ 57.315159][ T6680] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 57.325198][ T6680] Workqueue: qrtr_ns_handler qrtr_ns_worker [ 57.331060][ T6680] Call Trace: [ 57.334350][ T6680] dump_stack+0x198/0x1fd [ 57.338675][ T6680] panic+0x382/0x7fb [ 57.342564][ T6680] ? __warn_printk+0xf3/0xf3 [ 57.347133][ T6680] ? _raw_spin_unlock+0x24/0x40 [ 57.351959][ T6680] ? __printk_safe_exit+0x5/0x10 [ 57.356878][ T6680] ? console_unlock+0x733/0xe60 [ 57.361705][ T6680] ? __warn.cold+0x5/0x4b [ 57.366010][ T6680] ? __warn+0xd6/0x1f2 [ 57.370058][ T6680] ? refcount_warn_saturate+0x169/0x1e0 [ 57.375579][ T6680] __warn.cold+0x20/0x4b [ 57.379795][ T6680] ? wake_up_klogd.part.0+0x8e/0xd0 [ 57.384984][ T6680] ? refcount_warn_saturate+0x169/0x1e0 [ 57.390508][ T6680] report_bug+0x1bd/0x210 [ 57.394832][ T6680] handle_bug+0x38/0x90 [ 57.398962][ T6680] exc_invalid_op+0x14/0x40 [ 57.403447][ T6680] asm_exc_invalid_op+0x12/0x20 [ 57.408298][ T6680] RIP: 0010:refcount_warn_saturate+0x169/0x1e0 [ 57.414427][ T6680] Code: 07 31 ff 89 de e8 a7 58 b6 fd 84 db 0f 85 36 ff ff ff e8 7a 5c b6 fd 48 c7 c7 40 71 d8 88 c6 05 ef 51 94 07 01 e8 e9 99 86 fd <0f> 0b e9 17 ff ff ff e8 5b 5c b6 fd 0f b6 1d d4 51 94 07 31 ff 89 [ 57.434028][ T6680] RSP: 0018:ffffc9000a17f9d8 EFLAGS: 00010086 [ 57.440078][ T6680] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 [ 57.448032][ T6680] RDX: ffff888092a342c0 RSI: ffffffff815f5985 RDI: fffff5200142ff2d [ 57.455993][ T6680] RBP: 0000000000000002 R08: 0000000000000001 R09: ffff8880ae420f8b [ 57.463942][ T6680] R10: 0000000000000000 R11: 0000000000000000 R12: ffff8880a9219640 [ 57.471908][ T6680] R13: ffff88809f01e400 R14: ffff8880a04c5870 R15: ffff8880a04c5874 [ 57.479886][ T6680] ? vprintk_func+0x95/0x1d4 [ 57.484463][ T6680] ? refcount_warn_saturate+0x169/0x1e0 [ 57.489985][ T6680] qrtr_recvmsg+0x845/0x970 [ 57.494564][ T6680] ? qrtr_node_enqueue+0x1250/0x1250 [ 57.499850][ T6680] ? lock_is_held_type+0xbb/0xf0 [ 57.504784][ T6680] ? bpf_lsm_socket_recvmsg+0x5/0x10 [ 57.510090][ T6680] ? security_socket_recvmsg+0x8f/0xc0 [ 57.515534][ T6680] ? qrtr_node_enqueue+0x1250/0x1250 [ 57.520798][ T6680] kernel_recvmsg+0x110/0x160 [ 57.525472][ T6680] qrtr_ns_worker+0x15a/0x153b [ 57.530225][ T6680] ? lockdep_hardirqs_on_prepare+0x530/0x530 [ 57.536187][ T6680] ? ctrl_cmd_del_client+0x730/0x730 [ 57.541451][ T6680] ? lock_acquire+0x1f3/0xaf0 [ 57.546105][ T6680] ? process_one_work+0x85f/0x1670 [ 57.551203][ T6680] ? _raw_spin_unlock_irq+0x1f/0x80 [ 57.556399][ T6680] ? lock_is_held_type+0xbb/0xf0 [ 57.561342][ T6680] process_one_work+0x94c/0x1670 [ 57.566274][ T6680] ? lock_release+0x8f0/0x8f0 [ 57.570931][ T6680] ? pwq_dec_nr_in_flight+0x320/0x320 [ 57.576285][ T6680] ? rwlock_bug.part.0+0x90/0x90 [ 57.581201][ T6680] ? lockdep_hardirqs_off+0x96/0xd0 [ 57.586381][ T6680] worker_thread+0x64c/0x1120 [ 57.591041][ T6680] ? __kthread_parkme+0x13f/0x1e0 [ 57.596041][ T6680] ? process_one_work+0x1670/0x1670 [ 57.601275][ T6680] kthread+0x3b5/0x4a0 [ 57.605368][ T6680] ? __kthread_bind_mask+0xc0/0xc0 [ 57.610462][ T6680] ret_from_fork+0x1f/0x30 [ 58.710919][ T6680] Shutting down cpus with NMI [ 58.716830][ T6680] Kernel Offset: disabled [ 58.721205][ T6680] Rebooting in 86400 seconds..