=====================================
[ BUG: bad unlock balance detected! ]
PF_BRIDGE: RTM_SETLINK with unknown ifindex
4.9.67-gf26d3c7 #106 Not tainted
-------------------------------------
syz-executor0/12700 is trying to release lock ([  248.087216] PF_BRIDGE: RTM_SETLINK with unknown ifindex
mrt_lock) at:
but there are no more locks to release!

other info that might help us debug this:
1 lock held by syz-executor0/12700:
 #0:  (&p->lock){+.+.+.}, at: [<ffffffff815e4cdd>] seq_read+0xdd/0x1290 fs/seq_file.c:178

stack backtrace:
CPU: 0 PID: 12700 Comm: syz-executor0 Not tainted 4.9.67-gf26d3c7 #106
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 ffff8801d89d78e8 ffffffff81d906e9 ffffffff849ae8f8 ffff8801c9dc9800
 ffffffff834dec54 ffffffff849ae8f8 ffff8801c9dca088 ffff8801d89d7918
 ffffffff812353f4 dffffc0000000000 ffffffff849ae8f8 00000000ffffffff
Call Trace:
 [<ffffffff81d906e9>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81d906e9>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
 [<ffffffff812353f4>] print_unlock_imbalance_bug+0x174/0x1a0 kernel/locking/lockdep.c:3398
 [<ffffffff8123dec8>] __lock_release kernel/locking/lockdep.c:3540 [inline]
 [<ffffffff8123dec8>] lock_release+0x6f8/0xb80 kernel/locking/lockdep.c:3775
 [<ffffffff838a951a>] __raw_read_unlock include/linux/rwlock_api_smp.h:225 [inline]
 [<ffffffff838a951a>] _raw_read_unlock+0x1a/0x50 kernel/locking/spinlock.c:255
 [<ffffffff834dec54>] ipmr_mfc_seq_stop+0xe4/0x140 net/ipv6/ip6mr.c:553
 [<ffffffff815e5683>] seq_read+0xa83/0x1290 fs/seq_file.c:283
 [<ffffffff816be32f>] proc_reg_read+0xef/0x170 fs/proc/inode.c:202
 [<ffffffff81568cb1>] do_loop_readv_writev.part.17+0x141/0x1e0 fs/read_write.c:714
 [<ffffffff8156cb20>] do_loop_readv_writev fs/read_write.c:880 [inline]
 [<ffffffff8156cb20>] do_readv_writev+0x520/0x750 fs/read_write.c:874
 [<ffffffff8156cdd4>] vfs_readv+0x84/0xc0 fs/read_write.c:898
 [<ffffffff8156cef6>] do_readv+0xe6/0x250 fs/read_write.c:924
 [<ffffffff815703e7>] SYSC_readv fs/read_write.c:1011 [inline]
 [<ffffffff815703e7>] SyS_readv+0x27/0x30 fs/read_write.c:1008
 [<ffffffff838a9985>] entry_SYSCALL_64_fastpath+0x23/0xc6
device gre0 entered promiscuous mode
SELinux: unrecognized netlink message: protocol=0 nlmsg_type=770 sclass=netlink_route_socket pig=12855 comm=syz-executor5
SELinux: unrecognized netlink message: protocol=0 nlmsg_type=770 sclass=netlink_route_socket pig=12867 comm=syz-executor5
9pnet_virtio: no channels available for device H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H¨H
nla_parse: 17 callbacks suppressed
netlink: 1 bytes leftover after parsing attributes in process `syz-executor6'.
netlink: 1 bytes leftover after parsing attributes in process `syz-executor6'.
binder: 12901:12904 BC_DEAD_BINDER_DONE 0000000000000000 not found
binder: 12901:12905 BC_DEAD_BINDER_DONE 0000000000000000 not found
binder: 12900:12902 IncRefs 0 refcount change on invalid ref 0 ret -22
binder: 12900:12902 got transaction to invalid handle
binder: 12900:12902 transaction failed 29201/-22, size 0-0 line 3007
binder: 12900:12908 got transaction to invalid handle
binder: 12900:12908 transaction failed 29201/-22, size 0-0 line 3007
9pnet_virtio: no channels available for device H¨
binder: undelivered TRANSACTION_ERROR: 29201
binder: undelivered TRANSACTION_ERROR: 29201
SELinux: unrecognized netlink message: protocol=0 nlmsg_type=5521 sclass=netlink_route_socket pig=12970 comm=syz-executor5
SELinux: unrecognized netlink message: protocol=0 nlmsg_type=5521 sclass=netlink_route_socket pig=12970 comm=syz-executor5
binder: 13068:13069 IncRefs 0 refcount change on invalid ref 4 ret -22
binder: 13068:13069 got transaction to invalid handle
binder: 13068:13069 transaction failed 29201/-22, size 80-8 line 3007
binder: BINDER_SET_CONTEXT_MGR already set
binder: 13068:13069 ioctl 40046207 0 returned -16
binder: 13068:13069 IncRefs 0 refcount change on invalid ref 4 ret -22
binder: 13068:13073 got transaction to invalid handle
binder: 13068:13073 transaction failed 29201/-22, size 80-8 line 3007
binder: undelivered TRANSACTION_ERROR: 29201
binder: undelivered TRANSACTION_ERROR: 29201