=====================================
WARNING: bad unlock balance detected!
4.15.0-rc7+ #166 Not tainted
-------------------------------------
syz-executor6/13111 is trying to release lock (mrt_lock) at:
[<000000003fcf1005>] 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:
1 lock held by syz-executor6/13111:
 #0:  (&p->lock){+.+.}, at: [<00000000860d7022>] seq_read+0xd5/0x13d0 fs/seq_file.c:165

stack backtrace:
CPU: 0 PID: 13111 Comm: syz-executor6 Not tainted 4.15.0-rc7+ #166
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:3479
 __lock_release kernel/locking/lockdep.c:3685 [inline]
 lock_release+0x6fe/0xa40 kernel/locking/lockdep.c:3933
 __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
 traverse+0x3bc/0xa00 fs/seq_file.c:135
 seq_read+0x96a/0x13d0 fs/seq_file.c:189
 proc_reg_read+0xef/0x170 fs/proc/inode.c:217
 __vfs_read+0xef/0xa00 fs/read_write.c:411
 vfs_read+0x11e/0x350 fs/read_write.c:447
 SYSC_pread64 fs/read_write.c:611 [inline]
 SyS_pread64+0x15b/0x190 fs/read_write.c:598
 sys32_pread+0x39/0x50 arch/x86/ia32/sys_ia32.c:180
 do_syscall_32_irqs_on arch/x86/entry/common.c:327 [inline]
 do_fast_syscall_32+0x3ee/0xf9d arch/x86/entry/common.c:389
 entry_SYSENTER_compat+0x54/0x63 arch/x86/entry/entry_64_compat.S:129
RIP: 0023:0xf7f78c79
RSP: 002b:00000000f777408c EFLAGS: 00000296 ORIG_RAX: 00000000000000b4
RAX: ffffffffffffffda RBX: 0000000000000013 RCX: 0000000020160000
RDX: 0000000000001000 RSI: 000000000000004a RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
BUG: sleeping function called from invalid context at lib/usercopy.c:25
in_atomic(): 1, irqs_disabled(): 0, pid: 13111, name: syz-executor6
INFO: lockdep is turned off.
CPU: 0 PID: 13111 Comm: syz-executor6 Not tainted 4.15.0-rc7+ #166
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:6060
 __might_sleep+0x95/0x190 kernel/sched/core.c:6013
 __might_fault+0xab/0x1d0 mm/memory.c:4526
 _copy_to_user+0x2c/0xc0 lib/usercopy.c:25
 copy_to_user include/linux/uaccess.h:155 [inline]
 seq_read+0x875/0x13d0 fs/seq_file.c:212
 proc_reg_read+0xef/0x170 fs/proc/inode.c:217
 __vfs_read+0xef/0xa00 fs/read_write.c:411
 vfs_read+0x11e/0x350 fs/read_write.c:447
 SYSC_pread64 fs/read_write.c:611 [inline]
 SyS_pread64+0x15b/0x190 fs/read_write.c:598
 sys32_pread+0x39/0x50 arch/x86/ia32/sys_ia32.c:180
 do_syscall_32_irqs_on arch/x86/entry/common.c:327 [inline]
 do_fast_syscall_32+0x3ee/0xf9d arch/x86/entry/common.c:389
 entry_SYSENTER_compat+0x54/0x63 arch/x86/entry/entry_64_compat.S:129
RIP: 0023:0xf7f78c79
RSP: 002b:00000000f777408c EFLAGS: 00000296 ORIG_RAX: 00000000000000b4
RAX: ffffffffffffffda RBX: 0000000000000013 RCX: 0000000020160000
RDX: 0000000000001000 RSI: 000000000000004a RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
WARNING: CPU: 0 PID: 13111 at lib/usercopy.c:26 _copy_to_user+0xb5/0xc0 lib/usercopy.c:26