Date:   Thu, 16 Nov 2017 02:56:00 -0800
From:   syzbot 
        <bot+0415e5f62aec83dfecbd675dfd1e16d73be06542@...kaller.appspotmail.com>
To:     linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org,
        syzkaller-bugs@...glegroups.com, viro@...iv.linux.org.uk
Subject: WARNING in lock_release

Hello,

syzkaller hit the following crash on  
5515cf16e270538121e4fa9283fed86c6cfd8c9c
git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/master
compiler: gcc (GCC) 7.1.1 20170620
.config is attached
Raw console output is attached.
C reproducer is attached
syzkaller reproducer is attached. See https://goo.gl/kgGztJ
for information about syzkaller reproducers


RBP: 0000000000000086 R08: 0000000020000000 R09: 65732f636f003031
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000401d60
R13: 0000000000401df0 R14: 0000000000000000 R15: 0000000000000000
DEBUG_LOCKS_WARN_ON(depth <= 0)
------------[ cut here ]------------
WARNING: CPU: 0 PID: 3043 at kernel/locking/lockdep.c:3766 __lock_release  
kernel/locking/lockdep.c:3766 [inline]
WARNING: CPU: 0 PID: 3043 at kernel/locking/lockdep.c:3766  
lock_release+0x5de/0xd90 kernel/locking/lockdep.c:4023
Kernel panic - not syncing: panic_on_warn set ...

CPU: 0 PID: 3043 Comm: syzkaller384967 Not tainted  
4.14.0-rc8-next-20171109+ #39
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+0x1c4/0x1e0 kernel/panic.c:546
  report_bug+0x211/0x2d0 lib/bug.c:184
  fixup_bug+0x40/0x90 arch/x86/kernel/traps.c:176
  do_trap_no_signal arch/x86/kernel/traps.c:210 [inline]
  do_trap+0x260/0x390 arch/x86/kernel/traps.c:259
  do_error_trap+0x120/0x390 arch/x86/kernel/traps.c:296
  do_invalid_op+0x1b/0x20 arch/x86/kernel/traps.c:309
  invalid_op+0x18/0x20 arch/x86/entry/entry_64.S:926
RIP: 0010:__lock_release kernel/locking/lockdep.c:3766 [inline]
RIP: 0010:lock_release+0x5de/0xd90 kernel/locking/lockdep.c:4023
RSP: 0018:ffff8801ccfe7740 EFLAGS: 00010082
RAX: 000000000000001f RBX: 1ffff100399fceed RCX: 0000000000000000
RDX: 000000000000001f RSI: 1ffff100399fcea8 RDI: ffffed00399fcedc
RBP: ffff8801ccfe78b0 R08: 0000000000000001 R09: 0000000000000000
R10: ffff8801cceac580 R11: fffffbfff0e8546b R12: ffff8801ccfe7788
R13: ffff8801ccfe7888 R14: ffff8801cc018b98 R15: ffffffff8746ad60
  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+0x905/0xe20 fs/super.c:503
  sget+0xd2/0x120 fs/super.c:554
  mount_nodev+0x37/0x100 fs/super.c:1157
  devpts_mount+0x2c/0x40 fs/devpts/inode.c:481
  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+0xea1/0x2bb0 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: 0033:0x440439
RSP: 002b:00007ffdf34ca458 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000440439
RDX: 0000000020e3b000 RSI: 000000002059e000 RDI: 0000000020ae0ff4
RBP: 0000000000000086 R08: 0000000020000000 R09: 65732f636f003031
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000401d60
R13: 0000000000401df0 R14: 0000000000000000 R15: 0000000000000000
Dumping ftrace buffer:
    (ftrace buffer empty)
Kernel Offset: disabled
Rebooting in 86400 seconds..


---
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See https://goo.gl/tpsmEJ for details.
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