Debian GNU/Linux 9 syzkaller ttyS0

Warning: Permanently added '10.128.0.19' (ECDSA) to the list of known hosts.
executing program
syzkaller login: [   33.937317] 
[   33.939012] =============================
[   33.944929] WARNING: suspicious RCU usage
[   33.949101] 4.14.176-syzkaller #0 Not tainted
[   33.953781] -----------------------------
[   33.957934] net/sched/act_sample.c:95 suspicious rcu_dereference_protected() usage!
[   33.965799] 
[   33.965799] other info that might help us debug this:
[   33.965799] 
[   33.974217] 
[   33.974217] rcu_scheduler_active = 2, debug_locks = 1
[   33.981136] 1 lock held by syz-executor488/6336:
[   33.985949]  #0:  (rtnl_mutex){+.+.}, at: [<ffffffff8502c70d>] rtnetlink_rcv_msg+0x31d/0xb10
[   33.995258] 
[   33.995258] stack backtrace:
[   33.999855] CPU: 0 PID: 6336 Comm: syz-executor488 Not tainted 4.14.176-syzkaller #0
[   34.007724] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
[   34.017189] Call Trace:
[   34.019922]  dump_stack+0x13e/0x194
[   34.023588]  tcf_sample_init+0x71c/0x8c0
[   34.027632]  ? tcf_sample_act+0x9e0/0x9e0
[   34.031766]  tcf_action_init_1+0x51a/0x9f0
[   34.036064]  ? tcf_action_dump_old+0x80/0x80
[   34.040484]  ? find_held_lock+0x2d/0x110
[   34.044533]  ? avc_has_perm_noaudit+0x270/0x400
[   34.049188]  ? nla_parse+0x183/0x240
[   34.052883]  tcf_action_init+0x26d/0x400
[   34.056928]  ? tcf_action_init_1+0x9f0/0x9f0
[   34.061339]  ? lock_downgrade+0x6e0/0x6e0
[   34.065483]  ? memset+0x20/0x40
[   34.068745]  ? nla_parse+0x183/0x240
[   34.072441]  tc_ctl_action+0x2e3/0x513
[   34.076309]  ? tca_action_gd+0x7b0/0x7b0
[   34.080353]  ? rtnetlink_rcv_msg+0x2e8/0xb10
[   34.084752]  ? tca_action_gd+0x7b0/0x7b0
[   34.088793]  rtnetlink_rcv_msg+0x3be/0xb10
[   34.093010]  ? rtnl_bridge_getlink+0x7a0/0x7a0
[   34.097575]  ? save_trace+0x290/0x290
[   34.101353]  ? save_trace+0x290/0x290
[   34.105135]  netlink_rcv_skb+0x127/0x370
[   34.109176]  ? rtnl_bridge_getlink+0x7a0/0x7a0
[   34.113742]  ? netlink_ack+0x980/0x980
[   34.117625]  netlink_unicast+0x437/0x620
[   34.121669]  ? netlink_attachskb+0x600/0x600
[   34.126076]  netlink_sendmsg+0x733/0xbe0
[   34.130125]  ? netlink_unicast+0x620/0x620
[   34.134356]  ? SYSC_sendto+0x2b0/0x2b0
[   34.138238]  ? security_socket_sendmsg+0x83/0xb0
[   34.142994]  ? netlink_unicast+0x620/0x620
[   34.147205]  sock_sendmsg+0xc5/0x100
[   34.150900]  ___sys_sendmsg+0x70a/0x840
[   34.154872]  ? do_huge_pmd_anonymous_page+0xc63/0x11e0
[   34.160129]  ? copy_msghdr_from_user+0x380/0x380
[   34.165486]  ? lock_downgrade+0x6e0/0x6e0
[   34.169614]  ? __lru_cache_add+0x17b/0x250
[   34.173843]  ? do_raw_spin_unlock+0x164/0x250
[   34.178316]  ? _raw_spin_unlock+0x29/0x40
[   34.182459]  ? prep_transhuge_page+0xa0/0xa0
[   34.186866]  ? pud_val+0x6c/0xd0
[   34.190224]  ? pmd_val+0xd0/0xd0
[   34.193593]  ? trace_hardirqs_on+0x10/0x10
[   34.197856]  ? __handle_mm_fault+0x644/0x3280
[   34.202518]  ? save_trace+0x290/0x290
[   34.206303]  ? copy_page_range+0x1d70/0x1d70
[   34.210701]  ? __fget_light+0x16a/0x1f0
[   34.214659]  ? sockfd_lookup_light+0xb2/0x160
[   34.219134]  __sys_sendmsg+0xa3/0x120
[   34.222933]  ? SyS_shutdown+0x160/0x160
[   34.227159]  ? up_read+0x17/0x30
[   34.230503]  ? __do_page_fault+0x35b/0xb40
[   34.234841]  SyS_sendmsg+0x27/0x40
[   34.238362]  ? __sys_sendmsg+0x120/0x120
[   34.242406]  do_syscall_64+0x1d5/0x640
[   34.246274]  entry_SYSCALL_64_after_hwframe+0x42/0xb7
[   34.251456] RIP: 0033:0x440369
[   34.254626] RSP: 002b:00007ffc2fdb2588 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
[   34.262314] RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 0000000000440369
[   34.269576] RDX: 0000000000000000 RSI: 0000000020002980 RDI: 0000000000000003
[   34.276828] RBP: 00000000006ca018 R08: 000000000000000b R09: 00000000004002c8
[   34.284090] R10: 0000000000000040 R11: 0000000000000