TITLE: WARNING: locking bug in destroy_unused_super
TYPE: LOCKDEP
PANICKED: Y

[  151.124617] ------------[ cut here ]------------
[  151.124619] DEBUG_LOCKS_WARN_ON(depth <= 0)
[  151.124680] WARNING: CPU: 1 PID: 21689 at kernel/locking/lockdep.c:3676 lock_release+0x6e6/0xa40
[  151.124684] Kernel panic - not syncing: panic_on_warn set ...
[  151.124684] 
[  151.124689] CPU: 1 PID: 21689 Comm: syz-executor4 Not tainted 4.15.0-rc3+ #224
[  151.124693] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
[  151.124694] Call Trace:
[  151.124702]  dump_stack+0x194/0x257
[  151.124711]  ? arch_local_irq_restore+0x53/0x53
[  151.124719]  ? vsnprintf+0x1ed/0x1900
[  151.124727]  panic+0x1e4/0x41c
[  151.124734]  ? refcount_error_report+0x214/0x214
[  151.124741]  ? show_regs_print_info+0x18/0x18
[  151.124749]  ? __warn+0x1c1/0x200
[  151.124757]  ? lock_release+0x6e6/0xa40
[  151.124763]  __warn+0x1dc/0x200
[  151.124769]  ? lock_release+0x6e6/0xa40
[  151.124778]  report_bug+0x211/0x2d0
[  151.124788]  fixup_bug.part.11+0x37/0x80
[  151.124795]  do_error_trap+0x2d7/0x3e0
[  151.124803]  ? math_error+0x400/0x400
[  151.124809]  ? vprintk_emit+0x3ea/0x590
[  151.124822]  ? trace_hardirqs_off_thunk+0x1a/0x1c
[  151.124834]  do_invalid_op+0x1b/0x20
[  151.124841]  invalid_op+0x18/0x20
[  151.124847] RIP: 0010:lock_release+0x6e6/0xa40
[  151.124850] RSP: 0018:ffff8801c829f780 EFLAGS: 00010086
[  151.124856] RAX: dffffc0000000008 RBX: ffffffff8747a180 RCX: ffffffff8159a88e
[  151.124860] RDX: 0000000000010000 RSI: ffffc90002835000 RDI: 0000000000000000
[  151.124863] RBP: ffff8801c829f8b0 R08: 0000000000000001 R09: 0000000000000000
[  151.124866] R10: 0000000000000000 R11: fffffbfff0e872ef R12: ffff8801c829f888
[  151.124869] R13: ffff8801d09980c0 R14: ffff8801c829f7c8 R15: 1ffff10039053ef5
[  151.124878]  ? vprintk_func+0x5e/0xc0
[  151.124889]  ? destroy_unused_super.part.7+0x18/0xd0
[  151.124896]  ? lock_downgrade+0x980/0x980
[  151.124904]  ? __kmalloc+0x46e/0x760
[  151.124911]  ? lockdep_init_map+0x9/0x10
[  151.124918]  ? up_read+0x1a/0x40
[  151.124924]  ? memcg_put_cache_ids+0x10/0x20
[  151.124933]  ? __list_lru_init+0x35c/0x750
[  151.124941]  up_write+0x6b/0x120
[  151.124947]  ? up_read+0x40/0x40
[  151.124954]  ? __lockdep_init_map+0xe4/0x650
[  151.124963]  destroy_unused_super.part.7+0x18/0xd0
[  151.124969]  sget_userns+0x909/0xe20
[  151.124975]  ? get_anon_bdev+0x2a0/0x2a0
[  151.124984]  ? destroy_unused_super.part.7+0xd0/0xd0
[  151.124991]  ? cred_has_capability+0x1a0/0x3d0
[  151.124998]  ? selinux_ipv4_output+0x40/0x40
[  151.125013]  ? free_pages+0x51/0x90
[  151.125021]  ? selinux_sb_copy_data+0x403/0x610
[  151.125030]  ? selinux_capable+0x36/0x40
[  151.125039]  ? security_capable+0x8e/0xc0
[  151.125046]  ? get_anon_bdev+0x2a0/0x2a0
[  151.125051]  ? ns_capable_common+0xcf/0x160
[  151.125058]  ? get_anon_bdev+0x2a0/0x2a0
[  151.125064]  sget+0xd2/0x120
[  151.125070]  ? __get_fs_type+0x8a/0xc0
[  151.125077]  ? shmem_remount_fs+0x6c0/0x6c0
[  151.125084]  mount_nodev+0x37/0x100
[  151.125091]  shmem_mount+0x2c/0x40
[  151.125098]  mount_fs+0x66/0x2d0
[  151.125107]  vfs_kern_mount.part.26+0xc6/0x4a0
[  151.125115]  ? may_umount+0xa0/0xa0
[  151.125121]  ? _raw_read_unlock+0x22/0x30
[  151.125127]  ? __get_fs_type+0x8a/0xc0
[  151.125135]  do_mount+0xea4/0x2bb0
[  151.125144]  ? copy_mount_string+0x40/0x40
[  151.125150]  ? trace_hardirqs_on_caller+0x421/0x5c0
[  151.125157]  ? trace_hardirqs_on_thunk+0x1a/0x1c
[  151.125165]  ? retint_kernel+0x10/0x10
[  151.125174]  ? copy_mount_options+0x18b/0x2e0
[  151.125182]  ? copy_mount_options+0x190/0x2e0
[  151.125188]  ? copy_mount_options+0x1f4/0x2e0
[  151.125195]  SyS_mount+0xab/0x120
[  151.125202]  entry_SYSCALL_64_fastpath+0x1f/0x96
[  151.125205] RIP: 0033:0x452a39
[  151.125208] RSP: 002b:00007f207292dc58 EFLAGS: 00000212 ORIG_RAX: 00000000000000a5
[  151.125214] RAX: ffffffffffffffda RBX: 00007f207292daa0 RCX: 0000000000452a39
[  151.125217] RDX: 00000000204df000 RSI: 00000000209e5000 RDI: 00000000209dd000
[  151.125220] RBP: 00007f207292da90 R08: 0000000020000000 R09: 0000000000000000
[  151.125222] R10: 0000000000000000 R11: 0000000000000212 R12: 00000000004b75fb
[  151.125225] R13: 00007f207292dbc8 R14: 00000000004b75fb R15: 0000000000000000
[  151.125609] Dumping ftrace buffer:
[  151.125612]    (ftrace buffer empty)
[  151.125614] Kernel Offset: disabled
[  151.833421] Rebooting in 86400 seconds..
