IPVS: Creating netns size=2536 id=1

=====================================
[ BUG: bad unlock balance detected! ]
4.9.80-g20c8a00 #38 Not tainted
-------------------------------------
syz-executor0/3826 is trying to release lock (mrt_lock) at:
[<ffffffff834e8f44>] ipmr_mfc_seq_stop+0xe4/0x140 net/ipv6/ip6mr.c:553
but there are no more locks to release!

other info that might help us debug this:
2 locks held by syz-executor0/3826:
 #0:  (sb_writers#7){.+.+.+}, at: [<ffffffff81572fbf>] file_start_write include/linux/fs.h:2621 [inline]
 #0:  (sb_writers#7){.+.+.+}, at: [<ffffffff81572fbf>] do_sendfile+0x9ff/0xd30 fs/read_write.c:1400
 #1:  (&p->lock){+.+.+.}, at: [<ffffffff815e8e5d>] seq_read+0xdd/0x1290 fs/seq_file.c:178

stack backtrace:
CPU: 0 PID: 3826 Comm: syz-executor0 Not tainted 4.9.80-g20c8a00 #38
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 ffff8801d847f238 ffffffff81d94b69 ffffffff849b6cf8 ffff8801b20c6000
 ffffffff834e8f44 ffffffff849b6cf8 ffff8801b20c6888 ffff8801d847f268
 ffffffff81237e04 dffffc0000000000 ffffffff849b6cf8 00000000ffffffff
Call Trace:
 [<ffffffff81d94b69>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81d94b69>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
 [<ffffffff81237e04>] print_unlock_imbalance_bug+0x174/0x1a0 kernel/locking/lockdep.c:3398
 [<ffffffff812408d8>] __lock_release kernel/locking/lockdep.c:3540 [inline]
 [<ffffffff812408d8>] lock_release+0x6f8/0xb80 kernel/locking/lockdep.c:3775
 [<ffffffff838b303a>] __raw_read_unlock include/linux/rwlock_api_smp.h:225 [inline]
 [<ffffffff838b303a>] _raw_read_unlock+0x1a/0x50 kernel/locking/spinlock.c:255
 [<ffffffff834e8f44>] ipmr_mfc_seq_stop+0xe4/0x140 net/ipv6/ip6mr.c:553
 [<ffffffff815e9803>] seq_read+0xa83/0x1290 fs/seq_file.c:283
 [<ffffffff816c24ff>] proc_reg_read+0xef/0x170 fs/proc/inode.c:202
 [<ffffffff8156cc21>] do_loop_readv_writev.part.17+0x141/0x1e0 fs/read_write.c:714
 [<ffffffff81570a90>] do_loop_readv_writev fs/read_write.c:880 [inline]
 [<ffffffff81570a90>] do_readv_writev+0x520/0x750 fs/read_write.c:874
 [<ffffffff81570d44>] vfs_readv+0x84/0xc0 fs/read_write.c:898
 [<ffffffff8160ffff>] kernel_readv fs/splice.c:363 [inline]
 [<ffffffff8160ffff>] default_file_splice_read+0x43f/0x7a0 fs/splice.c:435
 [<ffffffff8160f0fa>] do_splice_to+0x10a/0x160 fs/splice.c:899
 [<ffffffff8160f39d>] splice_direct_to_actor+0x24d/0x800 fs/splice.c:971
 [<ffffffff8160faf7>] do_splice_direct+0x1a7/0x270 fs/splice.c:1080
 [<ffffffff81572b0b>] do_sendfile+0x54b/0xd30 fs/read_write.c:1401
 [<ffffffff81574a61>] SYSC_sendfile64 fs/read_write.c:1456 [inline]
 [<ffffffff81574a61>] SyS_sendfile64+0xd1/0x160 fs/read_write.c:1448
 [<ffffffff81006fc7>] do_syscall_32_irqs_on arch/x86/entry/common.c:322 [inline]
 [<ffffffff81006fc7>] do_fast_syscall_32+0x2f7/0x890 arch/x86/entry/common.c:384
 [<ffffffff838b4db4>] entry_SYSENTER_compat+0x74/0x83 arch/x86/entry/entry_64_compat.S:127