=====================================
WARNING: bad unlock balance detected!
4.15.0+ #287 Not tainted
-------------------------------------
syz-executor7/22863 is trying to release lock (mrt_lock) at:
[<000000007dd3adb8>] ipmr_mfc_seq_stop+0xe1/0x130 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-executor7/22863:
 #0:  (&f->f_pos_lock){+.+.}, at: [<00000000f0561583>] __fdget_pos+0x12b/0x190 fs/file.c:770
 #1:  (&p->lock){+.+.}, at: [<00000000ba84b253>] seq_read+0xd5/0x13d0 fs/seq_file.c:165

stack backtrace:
CPU: 1 PID: 22863 Comm: syz-executor7 Not tainted 4.15.0+ #287
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0x194/0x257 lib/dump_stack.c:53
 print_unlock_imbalance_bug+0x12f/0x140 kernel/locking/lockdep.c:3484
 __lock_release kernel/locking/lockdep.c:3691 [inline]
 lock_release+0x6fe/0xa40 kernel/locking/lockdep.c:3939
 __raw_read_unlock include/linux/rwlock_api_smp.h:225 [inline]
 _raw_read_unlock+0x1a/0x30 kernel/locking/spinlock.c:248
 ipmr_mfc_seq_stop+0xe1/0x130 net/ipv6/ip6mr.c:553
 seq_read+0xc42/0x13d0 fs/seq_file.c:277
 proc_reg_read+0xef/0x170 fs/proc/inode.c:217
 do_loop_readv_writev fs/read_write.c:673 [inline]
 do_iter_read+0x3d2/0x5a0 fs/read_write.c:897
 vfs_readv+0x121/0x1c0 fs/read_write.c:959
 do_readv+0xfc/0x2a0 fs/read_write.c:992
 SYSC_readv fs/read_write.c:1079 [inline]
 SyS_readv+0x27/0x30 fs/read_write.c:1076
 entry_SYSCALL_64_fastpath+0x29/0xa0
RIP: 0033:0x453299
RSP: 002b:00007f63e6e1ec58 EFLAGS: 00000212 ORIG_RAX: 0000000000000013
RAX: ffffffffffffffda RBX: 000000000071bea0 RCX: 0000000000453299
RDX: 0000000000000004 RSI: 00000000201d2fc0 RDI: 0000000000000013
RBP: 0000000000000445 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000212 R12: 00000000006f5718
R13: 00000000ffffffff R14: 00007f63e6e1f6d4 R15: 0000000000000000
BUG: sleeping function called from invalid context at lib/usercopy.c:25
in_atomic(): 1, irqs_disabled(): 0, pid: 22863, name: syz-executor7
INFO: lockdep is turned off.
CPU: 1 PID: 22863 Comm: syz-executor7 Not tainted 4.15.0+ #287
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0x194/0x257 lib/dump_stack.c:53
 ___might_sleep+0x2b2/0x470 kernel/sched/core.c:6114
 __might_sleep+0x95/0x190 kernel/sched/core.c:6067
 __might_fault+0xab/0x1d0 mm/memory.c:4532
 _copy_to_user+0x2c/0xc0 lib/usercopy.c:25
 copy_to_user include/linux/uaccess.h:155 [inline]
 seq_read+0xcb4/0x13d0 fs/seq_file.c:279
 proc_reg_read+0xef/0x170 fs/proc/inode.c:217
 do_loop_readv_writev fs/read_write.c:673 [inline]
 do_iter_read+0x3d2/0x5a0 fs/read_write.c:897
 vfs_readv+0x121/0x1c0 fs/read_write.c:959
 do_readv+0xfc/0x2a0 fs/read_write.c:992
 SYSC_readv fs/read_write.c:1079 [inline]
 SyS_readv+0x27/0x30 fs/read_write.c:1076
 entry_SYSCALL_64_fastpath+0x29/0xa0
RIP: 0033:0x453299
RSP: 002b:00007f63e6e1ec58 EFLAGS: 00000212 ORIG_RAX: 0000000000000013
RAX: ffffffffffffffda RBX: 000000000071bea0 RCX: 0000000000453299
RDX: 0000000000000004 RSI: 00000000201d2fc0 RDI: 0000000000000013
RBP: 0000000000000445 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000212 R12: 00000000006f5718
R13: 00000000ffffffff R14: 00007f63e6e1f6d4 R15: 0000000000000000
WARNING: CPU: 1 PID: 22863 at lib/usercopy.c:26 _copy_to_user+0xb5/0xc0 lib/usercopy.c:26