===============================
[ INFO: suspicious RCU usage. ]
4.9.98-g9731a2d #22 Not tainted
-------------------------------
netlink: 20 bytes leftover after parsing attributes in process `syz-executor5'.
kernel/rcu/tree_plugin.h:672 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 udevd/2364:
 #0:  (rcu_read_lock){......}, at: [<ffffffff8159dcdd>] path_init+0xf4d/0x1580 include/linux/compiler.h:243
 #1:  (rcu_callback){......}, at: [<ffffffff8128586e>] __rcu_reclaim kernel/rcu/rcu.h:108 [inline]
 #1:  (rcu_callback){......}, at: [<ffffffff8128586e>] rcu_do_batch kernel/rcu/tree.c:2789 [inline]
 #1:  (rcu_callback){......}, at: [<ffffffff8128586e>] invoke_rcu_callbacks kernel/rcu/tree.c:3053 [inline]
 #1:  (rcu_callback){......}, at: [<ffffffff8128586e>] __rcu_process_callbacks kernel/rcu/tree.c:3020 [inline]
 #1:  (rcu_callback){......}, at: [<ffffffff8128586e>] rcu_process_callbacks+0x98e/0x12b0 kernel/rcu/tree.c:3037

stack backtrace:
CPU: 0 PID: 2364 Comm: udevd Not tainted 4.9.98-g9731a2d #22
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 ffff8801db207d60 ffffffff81eb0ee9 ffff8801baef3000 0000000000000000
 0000000000000002 ffffffff83c6da00 ffff8801d3f23a58 ffff8801db207d90
 ffffffff81423ea9 ffff8801d3f23900 ffff8801b760dd48 ffff8801b760d548
Call Trace:
 <IRQ> [ 1534.903892]  [<ffffffff81eb0ee9>] __dump_stack lib/dump_stack.c:15 [inline]
 <IRQ> [ 1534.903892]  [<ffffffff81eb0ee9>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
 [<ffffffff81423ea9>] lockdep_rcu_suspicious.cold.48+0x110/0x141 kernel/locking/lockdep.c:4455
 [<ffffffff81282108>] synchronize_rcu+0x68/0x90 kernel/rcu/tree_plugin.h:669
 [<ffffffff836b7aca>] __l2tp_session_unhash+0x38a/0x520 net/l2tp/l2tp_core.c:1796
 [<ffffffff836b7e57>] l2tp_tunnel_closeall+0x1f7/0x350 net/l2tp/l2tp_core.c:1364
 [<ffffffff836b8712>] l2tp_tunnel_destruct+0x2f2/0x590 net/l2tp/l2tp_core.c:1324
 [<ffffffff8301d095>] __sk_destruct+0x55/0x590 net/core/sock.c:1428
 [<ffffffff8128578e>] __rcu_reclaim kernel/rcu/rcu.h:118 [inline]
 [<ffffffff8128578e>] rcu_do_batch kernel/rcu/tree.c:2789 [inline]
 [<ffffffff8128578e>] invoke_rcu_callbacks kernel/rcu/tree.c:3053 [inline]
 [<ffffffff8128578e>] __rcu_process_callbacks kernel/rcu/tree.c:3020 [inline]
 [<ffffffff8128578e>] rcu_process_callbacks+0x8ae/0x12b0 kernel/rcu/tree.c:3037
 [<ffffffff839fb23b>] __do_softirq+0x20b/0x937 kernel/softirq.c:284
 [<ffffffff81149037>] invoke_softirq kernel/softirq.c:364 [inline]
 [<ffffffff81149037>] irq_exit+0x147/0x190 kernel/softirq.c:405
 [<ffffffff839f9e21>] exiting_irq arch/x86/include/asm/apic.h:659 [inline]
 [<ffffffff839f9e21>] smp_apic_timer_interrupt+0x81/0xa0 arch/x86/kernel/apic/apic.c:960
 [<ffffffff839f5fb0>] apic_timer_interrupt+0xa0/0xb0 arch/x86/entry/entry_64.S:648
 <EOI> [ 1535.017557]  [<ffffffff8159049e>] ? do_inode_permission fs/namei.c:381 [inline]
 <EOI> [ 1535.017557]  [<ffffffff8159049e>] ? __inode_permission2+0x2e/0x2d0 fs/namei.c:427
 [<ffffffff8159079f>] inode_permission2+0x2f/0x110 fs/namei.c:485
 [<ffffffff815a0055>] may_lookup fs/namei.c:1683 [inline]
 [<ffffffff815a0055>] link_path_walk+0x195/0x1200 fs/namei.c:2064
 [<ffffffff815a13b4>] path_lookupat.isra.41+0x1b4/0x410 fs/namei.c:2282
 [<ffffffff815a6e37>] filename_lookup.part.55+0x177/0x370 fs/namei.c:2317
 [<ffffffff815a71f3>] filename_lookup fs/namei.c:2310 [inline]
 [<ffffffff815a71f3>] user_path_at_empty+0x53/0x70 fs/namei.c:2578
 [<ffffffff8157e1d6>] user_path_at include/linux/namei.h:55 [inline]
 [<ffffffff8157e1d6>] vfs_fstatat+0xc6/0x170 fs/stat.c:106
 [<ffffffff8157f386>] vfs_stat fs/stat.c:123 [inline]
 [<ffffffff8157f386>] SYSC_newstat+0x86/0xf0 fs/stat.c:270
 [<ffffffff8157f78d>] SyS_newstat+0x1d/0x30 fs/stat.c:266
 [<ffffffff81006316>] do_syscall_64+0x1a6/0x490 arch/x86/entry/common.c:282
 [<ffffffff839f4653>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb
ODEBUG: object ffff8801db207ce8 is NOT on stack ffff8801baf58000, but annotated
------------[ cut here ]------------
WARNING: CPU: 0 PID: 2364 at lib/debugobjects.c:303 debug_object_is_on_stack lib/debugobjects.c:303 [inline]
WARNING: CPU: 0 PID: 2364 at lib/debugobjects.c:303 __debug_object_init.cold.10+0x6b/0x2b0 lib/debugobjects.c:329