SELinux: unrecognized netlink message: protocol=0 nlmsg_type=8241 sclass=netlink_route_socket pig=23281 comm=syz-executor7
TCP: request_sock_TCPv6: Possible SYN flooding on port 20002. Sending cookies.  Check SNMP counters.

===============================
[ INFO: suspicious RCU usage. ]
4.9.118-g47b77b8 #20 Not tainted
-------------------------------
kernel/rcu/tree_plugin.h:678 Illegal synchronize_rcu() in RCU read-side critical section!

other info that might help us debug this:


rcu_scheduler_active = 2, debug_locks = 0
2 locks held by syz-executor1/23263:
 #0:  (rcu_read_lock){......}, at: [<ffffffff8342c1c0>] sock_rps_record_flow include/net/sock.h:894 [inline]
 #0:  (rcu_read_lock){......}, at: [<ffffffff8342c1c0>] inet_recvmsg+0xd0/0x4c0 net/ipv4/af_inet.c:799
 #1:  (rcu_callback){......}, at: [<ffffffff8128788e>] __rcu_reclaim kernel/rcu/rcu.h:108 [inline]
 #1:  (rcu_callback){......}, at: [<ffffffff8128788e>] rcu_do_batch kernel/rcu/tree.c:2789 [inline]
 #1:  (rcu_callback){......}, at: [<ffffffff8128788e>] invoke_rcu_callbacks kernel/rcu/tree.c:3053 [inline]
 #1:  (rcu_callback){......}, at: [<ffffffff8128788e>] __rcu_process_callbacks kernel/rcu/tree.c:3020 [inline]
 #1:  (rcu_callback){......}, at: [<ffffffff8128788e>] rcu_process_callbacks+0x98e/0x12b0 kernel/rcu/tree.c:3037

stack backtrace:
CPU: 0 PID: 23263 Comm: syz-executor1 Not tainted 4.9.118-g47b77b8 #20
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 ffff8801db207d60 ffffffff81eb4b89 ffff88019dcde000 0000000000000000
 0000000000000002 ffffffff83c6df20 ffff88019e58e8d8 ffff8801db207d90
 ffffffff814262c0 ffff88019e58e780 ffff8801a1026e48 ffff8801a1026648
Call Trace:
 <IRQ> 
 [<ffffffff81eb4b89>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81eb4b89>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
 [<ffffffff814262c0>] lockdep_rcu_suspicious.cold.48+0x110/0x141 kernel/locking/lockdep.c:4455
 [<ffffffff81284128>] synchronize_rcu+0x68/0x90 kernel/rcu/tree_plugin.h:675
 [<ffffffff836bfc1a>] __l2tp_session_unhash+0x38a/0x520 net/l2tp/l2tp_core.c:1796
 [<ffffffff836bffa7>] l2tp_tunnel_closeall+0x1f7/0x350 net/l2tp/l2tp_core.c:1364
 [<ffffffff836c0862>] l2tp_tunnel_destruct+0x2f2/0x590 net/l2tp/l2tp_core.c:1324
 [<ffffffff830230f5>] __sk_destruct+0x55/0x590 net/core/sock.c:1428
 [<ffffffff812877ae>] __rcu_reclaim kernel/rcu/rcu.h:118 [inline]
 [<ffffffff812877ae>] rcu_do_batch kernel/rcu/tree.c:2789 [inline]
 [<ffffffff812877ae>] invoke_rcu_callbacks kernel/rcu/tree.c:3053 [inline]
 [<ffffffff812877ae>] __rcu_process_callbacks kernel/rcu/tree.c:3020 [inline]
 [<ffffffff812877ae>] rcu_process_callbacks+0x8ae/0x12b0 kernel/rcu/tree.c:3037
 [<ffffffff83a0367b>] __do_softirq+0x20b/0x937 kernel/softirq.c:284
 [<ffffffff8114b277>] invoke_softirq kernel/softirq.c:364 [inline]
 [<ffffffff8114b277>] irq_exit+0x147/0x190 kernel/softirq.c:405
 [<ffffffff83a02261>] exiting_irq arch/x86/include/asm/apic.h:659 [inline]
 [<ffffffff83a02261>] smp_apic_timer_interrupt+0x81/0xa0 arch/x86/kernel/apic/apic.c:960
 [<ffffffff839fe3f0>] apic_timer_interrupt+0xa0/0xb0 arch/x86/entry/entry_64.S:648
 <EOI> 
 [<ffffffff8127c210>] rcu_read_lock_held+0x90/0xc0 kernel/rcu/update.c:295
 [<ffffffff8342c4f1>] sock_rps_record_flow_hash include/net/sock.h:885 [inline]
 [<ffffffff8342c4f1>] sock_rps_record_flow include/net/sock.h:894 [inline]
 [<ffffffff8342c4f1>] inet_recvmsg+0x401/0x4c0 net/ipv4/af_inet.c:799
 [<ffffffff8301251c>] sock_recvmsg_nosec+0x8c/0xb0 net/socket.c:738
 [<ffffffff8301adf2>] ___sys_recvmsg+0x242/0x550 net/socket.c:2129
 [<ffffffff8301d44d>] __sys_recvmmsg+0x25d/0x700 net/socket.c:2237
 [<ffffffff8301da89>] SYSC_recvmmsg net/socket.c:2313 [inline]
 [<ffffffff8301da89>] SyS_recvmmsg+0x199/0x1c0 net/socket.c:2302
 [<ffffffff81006316>] do_syscall_64+0x1a6/0x490 arch/x86/entry/common.c:282
 [<ffffffff839fca93>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb
ODEBUG: object ffff8801db207ce8 is NOT on stack ffff8801a1038000, but annotated
------------[ cut here ]------------
WARNING: CPU: 0 PID: 23263 at lib/debugobjects.c:303 debug_object_is_on_stack lib/debugobjects.c:303 [inline]
WARNING: CPU: 0 PID: 23263 at lib/debugobjects.c:303 __debug_object_init.cold.10+0x6b/0x2b0 lib/debugobjects.c:329