IPv6: ADDRCONF(NETDEV_CHANGE): hsr_slave_0: link becomes ready
IPv6: ADDRCONF(NETDEV_CHANGE): hsr_slave_1: link becomes ready
IPv6: ADDRCONF(NETDEV_CHANGE): hsr0: link becomes ready
8021q: adding VLAN 0 to HW filter on device batadv0
=====================================
WARNING: bad unlock balance detected!
5.0.0-rc6+ #77 Not tainted
-------------------------------------
syz-executor.0/8256 is trying to release lock (&file->mut) at:
[<ffffffff850bb25c>] ucma_destroy_id+0x24c/0x4a0 drivers/infiniband/core/ucma.c:628
but there are no more locks to release!

other info that might help us debug this:
1 lock held by syz-executor.0/8256:
 #0: 0000000074494fb5 (&file->mut){+.+.}, at: ucma_destroy_id+0x1e9/0x4a0 drivers/infiniband/core/ucma.c:626

stack backtrace:
CPU: 0 PID: 8256 Comm: syz-executor.0 Not tainted 5.0.0-rc6+ #77
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x172/0x1f0 lib/dump_stack.c:113
 print_unlock_imbalance_bug kernel/locking/lockdep.c:3391 [inline]
 print_unlock_imbalance_bug.cold+0x114/0x123 kernel/locking/lockdep.c:3368
 __lock_release kernel/locking/lockdep.c:3601 [inline]
 lock_release+0x67e/0xa00 kernel/locking/lockdep.c:3860
 __mutex_unlock_slowpath+0x8e/0x6b0 kernel/locking/mutex.c:1197
 mutex_unlock+0xd/0x10 kernel/locking/mutex.c:713
 ucma_destroy_id+0x24c/0x4a0 drivers/infiniband/core/ucma.c:628
 ucma_write+0x2da/0x3c0 drivers/infiniband/core/ucma.c:1689
 __vfs_write+0x116/0x8e0 fs/read_write.c:485
 vfs_write+0x20c/0x580 fs/read_write.c:549
 ksys_write+0xea/0x1f0 fs/read_write.c:598
 __do_sys_write fs/read_write.c:610 [inline]
 __se_sys_write fs/read_write.c:607 [inline]
 __x64_sys_write+0x73/0xb0 fs/read_write.c:607
 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x457e29
Code: ad b8 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 7b b8 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fa3b5be6c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000457e29
RDX: 0000000000000018 RSI: 0000000020000180 RDI: 0000000000000005
RBP: 000000000073bfa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fa3b5be76d4
R13: 00000000004cd790 R14: 00000000004dc9d0 R15: 00000000ffffffff