Debian GNU/Linux 9 syzkaller ttyS0

Warning: Permanently added '10.128.0.117' (ECDSA) to the list of known hosts.
executing program
syzkaller login: [   69.950059][ T8485] 
[   69.952576][ T8485] =============================
[   69.957434][ T8485] WARNING: suspicious RCU usage
[   69.962914][ T8485] 5.11.0-rc2-syzkaller #0 Not tainted
[   69.968318][ T8485] -----------------------------
[   69.973272][ T8485] include/net/sock.h:1974 suspicious rcu_dereference_protected() usage!
[   69.981969][ T8485] 
[   69.981969][ T8485] other info that might help us debug this:
[   69.981969][ T8485] 
[   69.992622][ T8485] 
[   69.992622][ T8485] rcu_scheduler_active = 2, debug_locks = 1
[   70.000873][ T8485] 1 lock held by syz-executor192/8485:
[   70.006589][ T8485]  #0: ffff888017a98120 (sk_lock-AF_INET6){+.+.}-{0:0}, at: inet_shutdown+0x7d/0x430
[   70.016214][ T8485] 
[   70.016214][ T8485] stack backtrace:
[   70.022183][ T8485] CPU: 1 PID: 8485 Comm: syz-executor192 Not tainted 5.11.0-rc2-syzkaller #0
[   70.030956][ T8485] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
[   70.041445][ T8485] Call Trace:
[   70.044723][ T8485]  dump_stack+0x107/0x163
[   70.049047][ T8485]  tcp_disconnect+0x19b7/0x1e80
[   70.055551][ T8485]  ? mark_held_locks+0x9f/0xe0
[   70.060349][ T8485]  mptcp_disconnect+0xb4/0x2b0
[   70.065139][ T8485]  inet_shutdown+0x260/0x430
[   70.069733][ T8485]  __sys_shutdown+0xf1/0x1b0
[   70.074755][ T8485]  ? __sys_shutdown_sock+0xa0/0xa0
[   70.079900][ T8485]  ? syscall_enter_from_user_mode+0x1d/0x50
[   70.085928][ T8485]  __x64_sys_shutdown+0x50/0x70
[   70.090916][ T8485]  do_syscall_64+0x2d/0x70
[   70.095456][ T8485]  entry_SYSCALL_64_after_hwframe+0x44/0xa9
[   70.101358][ T8485] RIP: 0033:0x440289
[   70.105250][ T8485] Code: 18 89 d0 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 7b 13 fc ff c3 66 2e 0f 1f 84 00 00 00 00
[   70.125301][ T8485] RSP: 002b:00007ffceae0ea38 EFLAGS: 00000246 ORIG_RAX: 0000000000000030
[   70.133725][ T8485] RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 0000000000440289
[   70.141691][ T8485] RDX: 0000000000440289 RSI: 0000000000000000 RDI: 0000000000000003
[   70.149840