Debian GNU/Linux 9 syzkaller ttyS0

Warning: Permanently added '10.128.10.18' (ECDSA) to the list of known hosts.
executing program
syzkaller login: [   67.060885][ T7091] IPVS: ftp: loaded support on port[0] = 21
[   67.100886][ T7091] netlink: 16 bytes leftover after parsing attributes in process `syz-executor827'.
[   67.151114][ T7091] ------------[ cut here ]------------
[   67.156807][ T7091] refcount_t: underflow; use-after-free.
[   67.165093][ T7091] WARNING: CPU: 1 PID: 7091 at lib/refcount.c:28 refcount_warn_saturate+0x1d1/0x1e0
[   67.174828][ T7091] Kernel panic - not syncing: panic_on_warn set ...
[   67.181404][ T7091] CPU: 1 PID: 7091 Comm: syz-executor827 Not tainted 5.6.0-next-20200410-syzkaller #0
[   67.190925][ T7091] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
[   67.200972][ T7091] Call Trace:
[   67.204275][ T7091]  dump_stack+0x188/0x20d
[   67.208589][ T7091]  ? refcount_warn_saturate+0x100/0x1e0
[   67.214118][ T7091]  panic+0x2e3/0x75c
[   67.218002][ T7091]  ? add_taint.cold+0x16/0x16
[   67.222669][ T7091]  ? __probe_kernel_read+0x188/0x1d0
[   67.227939][ T7091]  ? __warn.cold+0x14/0x35
[   67.232376][ T7091]  ? __warn+0xd5/0x1c8
[   67.236434][ T7091]  ? refcount_warn_saturate+0x1d1/0x1e0
[   67.242671][ T7091]  __warn.cold+0x2f/0x35
[   67.247460][ T7091]  ? refcount_warn_saturate+0x1d1/0x1e0
[   67.253094][ T7091]  report_bug+0x27b/0x2f0
[   67.258654][ T7091]  do_error_trap+0x12b/0x220
[   67.263278][ T7091]  ? refcount_warn_saturate+0x1d1/0x1e0
[   67.268818][ T7091]  do_invalid_op+0x32/0x40
[   67.273243][ T7091]  ? refcount_warn_saturate+0x1d1/0x1e0
[   67.278792][ T7091]  invalid_op+0x23/0x30
[   67.282944][ T7091] RIP: 0010:refcount_warn_saturate+0x1d1/0x1e0
[   67.289084][ T7091] Code: e9 db fe ff ff 48 89 df e8 9c 67 1a fe e9 8a fe ff ff e8 12 47 dc fd 48 c7 c7 40 6b 72 88 c6 05 6e ab ed 06 01 e8 97 7b ad fd <0f> 0b e9 af fe ff ff 0f 1f 84 00 00 00 00 00 41 56 41 55 41 54 55
[   67.309365][ T7091] RSP: 0018:ffffc90005737d38 EFLAGS: 00010286
[   67.315417][ T7091] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
[   67.323382][ T7091] RDX: 0000000000000000 RSI: ffffffff815ce251 RDI: fffff52000ae6f99
[   67.331356][ T7091] RBP: 0000000000000003 R08: ffff888091f70180 R09: ffffed1015ce66b1
[   67.339316][ T7091] R10: ffff8880ae733587 R11: ffffed1015ce66b0 R12: ffff888098ef8040
[   67.347272][ T7091] R13: ffff888098ef8044 R14: 00000000000002ab R15: ffff8880972da7c0
[   67.355246][ T7091]  ? vprintk_func+0x81/0x17e
[   67.359827][ T7091]  ? refcount_warn_saturate+0x1d1/0x1e0
[   67.365379][ T7091]  free_nsproxy+0x445/0x4a0
[   67.369879][ T7091]  switch_task_namespaces+0xaa/0xc0
[   67.375071][ T7091]  do_exit+0xb4e/0x2e10
[   67.379220][ T7091]  ? mm_update_next_owner+0x7a0/0x7a0
[   67.384587][ T7091]  ? up_read+0x1a8/0x750
[   67.388817][ T7091]  ? down_read_nested+0x430/0x430
[   67.394298][ T7091]  ? handle_mm_fault+0x29e/0x660
[   67.399236][ T7091]  do_group_exit+0x125/0x340
[   67.403835][ T7091]  __x64_sys_exit_group+0x3a/0x50
[   67.408851][ T7091]  do_syscall_64+0xf6/0x7d0
[   67.413382][ T7091]  entry_SYSCALL_64_after_hwframe+0x49/0xb3
[   67.419257][ T7091] RIP: 0033:0x43f998
[   67.423139][ T7091] Code: Bad RIP value.
[   67.427271][ T7091] RSP: 002b:00007fff211ea488 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
[   67.435664][ T7091] RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 000000000043f998
[   67.443646][ T7091] RDX: 0000000000000001 RSI: 000000000000003c RDI: 0000000000000001
[   67.451607][ T7091] RBP: 00000000004bfa10 R08: 00000000000000e7 R09: ffffffffffffffd0
[   67.459586][ T7091] R10: 0000000120080522 R11: 0000000000000246 R12: 0000000000000001
[   67.467644][ T7091] R13: 00000000006d11c0 R14: 0000000000000000 R15: 0000000000000000
[   67.477431][ T7091] Kernel Offset: disabled
[   67.481940][ T7091] Rebooting in 86400 seconds..