===============================
[ INFO: suspicious RCU usage. ]
4.9.112-g9e79039 #59 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
3 locks held by modprobe/12066:
 #0:  (rcu_read_lock){......}, at: [<ffffffff815a05ed>] path_init+0xf4d/0x1580 include/linux/compiler.h:243
 #1:  (rcu_read_lock){......}, at: [<ffffffff81cf61d0>] INIT_LIST_HEAD include/linux/list.h:28 [inline]
 #1:  (rcu_read_lock){......}, at: [<ffffffff81cf61d0>] avc_compute_av+0xb0/0x610 security/selinux/avc.c:975
 #2:  (rcu_callback){......}, at: [<ffffffff812878ae>] __rcu_reclaim kernel/rcu/rcu.h:108 [inline]
 #2:  (rcu_callback){......}, at: [<ffffffff812878ae>] rcu_do_batch kernel/rcu/tree.c:2789 [inline]
 #2:  (rcu_callback){......}, at: [<ffffffff812878ae>] invoke_rcu_callbacks kernel/rcu/tree.c:3053 [inline]
 #2:  (rcu_callback){......}, at: [<ffffffff812878ae>] __rcu_process_callbacks kernel/rcu/tree.c:3020 [inline]
 #2:  (rcu_callback){......}, at: [<ffffffff812878ae>] rcu_process_callbacks+0x98e/0x12b0 kernel/rcu/tree.c:3037

stack backtrace:
CPU: 0 PID: 12066 Comm: modprobe Not tainted 4.9.112-g9e79039 #59
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 ffff8801db207d60 ffffffff81eb3249 ffff8801d5028000 0000000000000000
 0000000000000002 ffffffff83c6df20 ffff8801d736e8d8 ffff8801db207d90
 ffffffff814260f0 ffff8801d736e780 ffff8801a54e1948 ffff8801a54e1148
Call Trace:
 <IRQ> [  344.051327]  [<ffffffff81eb3249>] __dump_stack lib/dump_stack.c:15 [inline]
 <IRQ> [  344.051327]  [<ffffffff81eb3249>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
 [<ffffffff814260f0>] lockdep_rcu_suspicious.cold.48+0x110/0x141 kernel/locking/lockdep.c:4455
 [<ffffffff81284148>] synchronize_rcu+0x68/0x90 kernel/rcu/tree_plugin.h:675
 [<ffffffff836bd15a>] __l2tp_session_unhash+0x38a/0x520 net/l2tp/l2tp_core.c:1796
 [<ffffffff836bd4e7>] l2tp_tunnel_closeall+0x1f7/0x350 net/l2tp/l2tp_core.c:1364
 [<ffffffff836bdda2>] l2tp_tunnel_destruct+0x2f2/0x590 net/l2tp/l2tp_core.c:1324
 [<ffffffff83021095>] __sk_destruct+0x55/0x590 net/core/sock.c:1428
 [<ffffffff812877ce>] __rcu_reclaim kernel/rcu/rcu.h:118 [inline]
 [<ffffffff812877ce>] rcu_do_batch kernel/rcu/tree.c:2789 [inline]
 [<ffffffff812877ce>] invoke_rcu_callbacks kernel/rcu/tree.c:3053 [inline]
 [<ffffffff812877ce>] __rcu_process_callbacks kernel/rcu/tree.c:3020 [inline]
 [<ffffffff812877ce>] rcu_process_callbacks+0x8ae/0x12b0 kernel/rcu/tree.c:3037
 [<ffffffff83a00b3b>] __do_softirq+0x20b/0x937 kernel/softirq.c:284
 [<ffffffff8114b297>] invoke_softirq kernel/softirq.c:364 [inline]
 [<ffffffff8114b297>] irq_exit+0x147/0x190 kernel/softirq.c:405
 [<ffffffff839ff721>] exiting_irq arch/x86/include/asm/apic.h:659 [inline]
 [<ffffffff839ff721>] smp_apic_timer_interrupt+0x81/0xa0 arch/x86/kernel/apic/apic.c:960
 [<ffffffff839fb8b0>] apic_timer_interrupt+0xa0/0xb0 arch/x86/entry/entry_64.S:648
 <EOI> [  344.165242]  [<ffffffff839f967f>] ? arch_local_irq_restore arch/x86/include/asm/paravirt.h:768 [inline]
 <EOI> [  344.165242]  [<ffffffff839f967f>] ? __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:162 [inline]
 <EOI> [  344.165242]  [<ffffffff839f967f>] ? _raw_spin_unlock_irqrestore+0x5f/0x70 kernel/locking/spinlock.c:191
 [<ffffffff81cf5649>] spin_unlock_irqrestore include/linux/spinlock.h:362 [inline]
 [<ffffffff81cf5649>] avc_reclaim_node security/selinux/avc.c:543 [inline]
 [<ffffffff81cf5649>] avc_alloc_node+0x289/0x3d0 security/selinux/avc.c:561
 [<ffffffff81cf6298>] avc_insert security/selinux/avc.c:672 [inline]
 [<ffffffff81cf6298>] avc_compute_av+0x178/0x610 security/selinux/avc.c:978
 [<ffffffff81cf7ed9>] avc_has_perm_noaudit+0x319/0x450 security/selinux/avc.c:1114
 [<ffffffff81d0031d>] selinux_inode_permission+0x32d/0x4b0 security/selinux/hooks.c:3038
 [<ffffffff81ceed69>] security_inode_permission+0xb9/0x100 security/security.c:611
 [<ffffffff81592e13>] __inode_permission2+0x93/0x2d0 fs/namei.c:435
 [<ffffffff815930af>] inode_permission2+0x2f/0x110 fs/namei.c:485
 [<ffffffff815a2965>] may_lookup fs/namei.c:1683 [inline]
 [<ffffffff815a2965>] link_path_walk+0x195/0x1200 fs/namei.c:2064
 [<ffffffff815a3cc4>] path_lookupat.isra.41+0x1b4/0x410 fs/namei.c:2282
 [<ffffffff815a9747>] filename_lookup.part.55+0x177/0x370 fs/namei.c:2317
 [<ffffffff815a9b03>] filename_lookup fs/namei.c:2310 [inline]
 [<ffffffff815a9b03>] user_path_at_empty+0x53/0x70 fs/namei.c:2578
 [<ffffffff8156bfee>] user_path_at include/linux/namei.h:55 [inline]
 [<ffffffff8156bfee>] SYSC_faccessat fs/open.c:395 [inline]
 [<ffffffff8156bfee>] SyS_faccessat fs/open.c:363 [inline]
 [<ffffffff8156bfee>] SYSC_access fs/open.c:443 [inline]
 [<ffffffff8156bfee>] SyS_access+0x20e/0x680 fs/open.c:441
 [<ffffffff81006316>] do_syscall_64+0x1a6/0x490 arch/x86/entry/common.c:282
 [<ffffffff839f9f53>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb
ODEBUG: object ffff8801db207ce8 is NOT on stack ffff8801d7400000, but annotated
------------[ cut here ]------------
WARNING: CPU: 0 PID: 12066 at lib/debugobjects.c:303 debug_object_is_on_stack lib/debugobjects.c:303 [inline]
WARNING: CPU: 0 PID: 12066 at lib/debugobjects.c:303 __debug_object_init.cold.10+0x6b/0x2b0 lib/debugobjects.c:329