RBP: 00007f207292da90 R08: 0000000020000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000212 R12: 00000000004b75fb
R13: 00007f207292dbc8 R14: 00000000004b75fb R15: 0000000000000000
------------[ cut here ]------------
DEBUG_LOCKS_WARN_ON(depth <= 0)
WARNING: CPU: 1 PID: 21689 at kernel/locking/lockdep.c:3676 __lock_release kernel/locking/lockdep.c:3676 [inline]
WARNING: CPU: 1 PID: 21689 at kernel/locking/lockdep.c:3676 lock_release+0x6e6/0xa40 kernel/locking/lockdep.c:3933
Kernel panic - not syncing: panic_on_warn set ...

CPU: 1 PID: 21689 Comm: syz-executor4 Not tainted 4.15.0-rc3+ #224
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
 panic+0x1e4/0x41c kernel/panic.c:183
 __warn+0x1dc/0x200 kernel/panic.c:547
 report_bug+0x211/0x2d0 lib/bug.c:184
 fixup_bug.part.11+0x37/0x80 arch/x86/kernel/traps.c:177
 fixup_bug arch/x86/kernel/traps.c:246 [inline]
 do_error_trap+0x2d7/0x3e0 arch/x86/kernel/traps.c:295
 do_invalid_op+0x1b/0x20 arch/x86/kernel/traps.c:314
 invalid_op+0x18/0x20 arch/x86/entry/entry_64.S:930
RIP: 0010:__lock_release kernel/locking/lockdep.c:3676 [inline]
RIP: 0010:lock_release+0x6e6/0xa40 kernel/locking/lockdep.c:3933
RSP: 0018:ffff8801c829f780 EFLAGS: 00010086
RAX: dffffc0000000008 RBX: ffffffff8747a180 RCX: ffffffff8159a88e
RDX: 0000000000010000 RSI: ffffc90002835000 RDI: 0000000000000000
RBP: ffff8801c829f8b0 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: fffffbfff0e872ef R12: ffff8801c829f888
R13: ffff8801d09980c0 R14: ffff8801c829f7c8 R15: 1ffff10039053ef5
 up_write+0x6b/0x120 kernel/locking/rwsem.c:131
 destroy_unused_super.part.7+0x18/0xd0 fs/super.c:163
 destroy_unused_super fs/super.c:505 [inline]
 alloc_super fs/super.c:258 [inline]
 sget_userns+0x909/0xe20 fs/super.c:503
 sget+0xd2/0x120 fs/super.c:554
 mount_nodev+0x37/0x100 fs/super.c:1157
 shmem_mount+0x2c/0x40 mm/shmem.c:3972
 mount_fs+0x66/0x2d0 fs/super.c:1219
 vfs_kern_mount.part.26+0xc6/0x4a0 fs/namespace.c:1037
 vfs_kern_mount fs/namespace.c:2509 [inline]
 do_new_mount fs/namespace.c:2512 [inline]
 do_mount+0xea4/0x2bb0 fs/namespace.c:2841
 SYSC_mount fs/namespace.c:3057 [inline]
 SyS_mount+0xab/0x120 fs/namespace.c:3034
 entry_SYSCALL_64_fastpath+0x1f/0x96
RIP: 0033:0x452a39
RSP: 002b:00007f207292dc58 EFLAGS: 00000212 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f207292daa0 RCX: 0000000000452a39
RDX: 00000000204df000 RSI: 00000000209e5000 RDI: 00000000209dd000
RBP: 00007f207292da90 R08: 0000000020000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000212 R12: 00000000004b75fb
R13: 00007f207292dbc8 R14: 00000000004b75fb R15: 0000000000000000
Dumping ftrace buffer:
   (ftrace buffer empty)
Kernel Offset: disabled
Rebooting in 86400 seconds..