syzbot

device gre0 entered promiscuous mode

=====================================
WARNING: bad unlock balance detected!
4.15.0-rc3+ #217 Not tainted
-------------------------------------
syz-executor3/11585 is trying to release lock (mrt_lock) at:
[<00000000bc41d8ed>] 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-executor3/11585:
 #0:  (&p->lock){+.+.}, at: [<0000000008138813>] seq_read+0xd5/0x13d0 fs/seq_file.c:165

stack backtrace:
CPU: 1 PID: 11585 Comm: syz-executor3 Not tainted 4.15.0-rc3+ #217
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:3561
 __lock_release kernel/locking/lockdep.c:3775 [inline]
 lock_release+0x5f9/0xda0 kernel/locking/lockdep.c:4023
 __raw_read_unlock include/linux/rwlock_api_smp.h:225 [inline]
 _raw_read_unlock+0x1a/0x30 kernel/locking/spinlock.c:255
 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
 do_loop_readv_writev fs/read_write.c:673 [inline]
 do_iter_read+0x3db/0x5b0 fs/read_write.c:897
 vfs_readv+0x121/0x1c0 fs/read_write.c:959
 do_preadv+0x11b/0x1a0 fs/read_write.c:1043
 SYSC_preadv fs/read_write.c:1093 [inline]
 SyS_preadv+0x30/0x40 fs/read_write.c:1088
 entry_SYSCALL_64_fastpath+0x1f/0x96
RIP: 0033:0x452a39
RSP: 002b:00007fd603daec58 EFLAGS: 00000212 ORIG_RAX: 0000000000000127
RAX: ffffffffffffffda RBX: 00000000007580d8 RCX: 0000000000452a39
RDX: 0000000000000001 RSI: 00000000208da000 RDI: 0000000000000014
RBP: 0000000000000048 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000040 R11: 0000000000000212 R12: 00000000006ee760
R13: 00000000ffffffff R14: 00007fd603daf6d4 R15: 0000000000000012
BUG: sleeping function called from invalid context at lib/usercopy.c:25
in_atomic(): 1, irqs_disabled(): 0, pid: 11585, name: syz-executor3
INFO: lockdep is turned off.
CPU: 1 PID: 11585 Comm: syz-executor3 Not tainted 4.15.0-rc3+ #217
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:4525
 _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
 do_loop_readv_writev fs/read_write.c:673 [inline]
 do_iter_read+0x3db/0x5b0 fs/read_write.c:897
 vfs_readv+0x121/0x1c0 fs/read_write.c:959
 do_preadv+0x11b/0x1a0 fs/read_write.c:1043
 SYSC_preadv fs/read_write.c:1093 [inline]
 SyS_preadv+0x30/0x40 fs/read_write.c:1088
 entry_SYSCALL_64_fastpath+0x1f/0x96
RIP: 0033:0x452a39
RSP: 002b:00007fd603daec58 EFLAGS: 00000212 ORIG_RAX: 0000000000000127
RAX: ffffffffffffffda RBX: 00000000007580d8 RCX: 0000000000452a39
RDX: 0000000000000001 RSI: 00000000208da000 RDI: 0000000000000014
RBP: 0000000000000048 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000040 R11: 0000000000000212 R12: 00000000006ee760
R13: 00000000ffffffff R14: 00007fd603daf6d4 R15: 0000000000000012
WARNING: CPU: 1 PID: 11585 at lib/usercopy.c:26 _copy_to_user+0xb5/0xc0 lib/usercopy.c:26