[  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...


Debian GNU/Linux 9 syzkaller ttyS0

Warning: Permanently added '10.128.0.16' (ECDSA) to the list of known hosts.
executing program
syzkaller login: [   58.107935][ T7019] IPVS: ftp: loaded support on port[0] = 21
[   58.193018][    T7] ------------[ cut here ]------------
[   58.199011][    T7] refcount_t: underflow; use-after-free.
[   58.206186][    T7] WARNING: CPU: 0 PID: 7 at lib/refcount.c:28 refcount_warn_saturate+0x1d1/0x1e0
[   58.215340][    T7] Kernel panic - not syncing: panic_on_warn set ...
[   58.221909][    T7] CPU: 0 PID: 7 Comm: kworker/u4:0 Not tainted 5.6.0-syzkaller #0
[   58.229728][    T7] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
[   58.239771][    T7] Workqueue: tc_filter_workqueue tcindex_destroy_work
[   58.246522][    T7] Call Trace:
[   58.249806][    T7]  dump_stack+0x188/0x20d
[   58.254119][    T7]  ? refcount_warn_saturate+0x120/0x1e0
[   58.259647][    T7]  panic+0x2e3/0x75c
[   58.263525][    T7]  ? add_taint.cold+0x16/0x16
[   58.268202][    T7]  ? __probe_kernel_read+0x188/0x1d0
[   58.273511][    T7]  ? __warn.cold+0x14/0x35
[   58.277905][    T7]  ? __warn+0xd5/0x1c8
[   58.281951][    T7]  ? refcount_warn_saturate+0x1d1/0x1e0
[   58.287487][    T7]  __warn.cold+0x2f/0x35
[   58.291724][    T7]  ? irq_work_queue+0xc3/0x100
[   58.296471][    T7]  ? refcount_warn_saturate+0x1d1/0x1e0
[   58.302023][    T7]  report_bug+0x27b/0x2f0
[   58.306356][    T7]  do_error_trap+0x12b/0x220
[   58.310926][    T7]  ? refcount_warn_saturate+0x1d1/0x1e0
[   58.316462][    T7]  do_invalid_op+0x32/0x40
[   58.320872][    T7]  ? refcount_warn_saturate+0x1d1/0x1e0
[   58.326397][    T7]  invalid_op+0x23/0x30
[   58.330536][    T7] RIP: 0010:refcount_warn_saturate+0x1d1/0x1e0
[   58.336666][    T7] Code: e9 db fe ff ff 48 89 df e8 2c 95 1e fe e9 8a fe ff ff e8 c2 81 e1 fd 48 c7 c7 40 c6 71 88 c6 05 42 be f1 06 01 e8 17 f6 b2 fd <0f> 0b e9 af fe ff ff 0f 1f 84 00 00 00 00 00 41 56 41 55 41 54 55
[   58.356410][    T7] RSP: 0018:ffffc90000cdfcf0 EFLAGS: 00010282
[   58.362474][    T7] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
[   58.370430][    T7] RDX: 0000000000000000 RSI: ffffffff815ca861 RDI: fffff5200019bf90
[   58.378441][    T7] RBP: 0000000000000003 R08: ffff8880a95a41c0 R09: ffffed1015cc66a1
[   58.386397][    T7] R10: ffffed1015cc66a0 R11: ffff8880ae633507 R12: ffff8880a81c8c2c
[   58.394349][    T7] R13: ffff8880a81c8c40 R14: ffff8880a9580e00 R15: ffff8880aa034800
[   58.402328][    T7]  ? vprintk_func+0x81/0x17e
[   58.406933][    T7]  tcindex_data_put+0xd1/0xf0
[   58.411602][    T7]  process_one_work+0x965/0x16a0
[   58.416552][    T7]  ? lock_release+0x800/0x800
[   58.421334][    T7]  ? pwq_dec_nr_in_flight+0x310/0x310
[   58.426697][    T7]  ? rwlock_bug.part.0+0x90/0x90
[   58.431621][    T7]  worker_thread+0x96/0xe20
[   58.436113][    T7]  ? process_one_work+0x16a0/0x16a0
[   58.441288][    T7]  kthread+0x388/0x470
[   58.445333][    T7]  ? kthread_mod_delayed_work+0x1a0/0x1a0
[   58.451029][    T7]  ret_from_fork+0x24/0x30
[   58.456926][    T7] Kernel Offset: disabled
[   58.461308][    T7] Rebooting in 86400 seconds..