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Date:   Wed, 04 Apr 2018 19:02:01 -0700
Message-ID: <f4f5e80803d0503e760569105376@google.com>
Subject: WARNING: kobject bug in sysfs_warn_dup
From:   syzbot <syzbot+ff87a28e665c163aa7f5@syzkaller.appspotmail.com>
To:     gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org,
        syzkaller-bugs@googlegroups.com
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Sender: linux-kernel-owner@vger.kernel.org
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Hello,

syzbot hit the following crash on upstream commit
3e968c9f1401088abc9a19ae6ff571644d37a355 (Wed Apr 4 21:19:24 2018 +0000)
Merge tag 'ext4_for_linus' of  
git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4
syzbot dashboard link:  
https://syzkaller.appspot.com/bug?extid=ff87a28e665c163aa7f5

C reproducer: https://syzkaller.appspot.com/x/repro.c?id=5104666266304512
syzkaller reproducer:  
https://syzkaller.appspot.com/x/repro.syz?id=5683447737614336
Raw console output:  
https://syzkaller.appspot.com/x/log.txt?id=5104818200772608
Kernel config:  
https://syzkaller.appspot.com/x/.config?id=9118669095563550941
compiler: gcc (GCC) 7.1.1 20170620

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+ff87a28e665c163aa7f5@syzkaller.appspotmail.com
It will help syzbot understand when the bug is fixed. See footer for  
details.
If you forward the report, please keep this part and the footer.

R10: 0000000000000000 R11: 0000000000000286 R12: 0000000000000003
R13: 0000000000000004 R14: 0000000000000000 R15: 0000000000000000
------------[ cut here ]------------
kobject_add_internal failed for nodev( with -EEXIST, don't try to register  
things with the same name in the same directory.
sysfs: cannot create duplicate filename '/fs/gfs2/nodev('
WARNING: CPU: 1 PID: 4473 at lib/kobject.c:238  
kobject_add_internal+0x8d4/0xbc0 lib/kobject.c:235
CPU: 0 PID: 4474 Comm: syzkaller533472 Not tainted 4.16.0+ #15
Kernel panic - not syncing: panic_on_warn set ...

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+0x1a7/0x27d lib/dump_stack.c:53
  sysfs_warn_dup+0x83/0xa0 fs/sysfs/dir.c:30
  sysfs_create_dir_ns+0x178/0x1d0 fs/sysfs/dir.c:58
  create_dir lib/kobject.c:69 [inline]
  kobject_add_internal+0x335/0xbc0 lib/kobject.c:227
  kobject_add_varg lib/kobject.c:364 [inline]
  kobject_init_and_add+0xf9/0x150 lib/kobject.c:436
  gfs2_sys_fs_add+0x1ff/0x580 fs/gfs2/sys.c:652
  fill_super+0x86f/0x1d70 fs/gfs2/ops_fstype.c:1118
  gfs2_mount+0x587/0x6e0 fs/gfs2/ops_fstype.c:1321
  mount_fs+0x66/0x2d0 fs/super.c:1222
  vfs_kern_mount.part.26+0xc6/0x4a0 fs/namespace.c:1037
  vfs_kern_mount fs/namespace.c:2514 [inline]
  do_new_mount fs/namespace.c:2517 [inline]
  do_mount+0xea4/0x2b90 fs/namespace.c:2847
  ksys_mount+0xab/0x120 fs/namespace.c:3063
  SYSC_mount fs/namespace.c:3077 [inline]
  SyS_mount+0x39/0x50 fs/namespace.c:3074
  do_syscall_64+0x281/0x940 arch/x86/entry/common.c:287
  entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x4432fa
RSP: 002b:00007ffda3d84538 EFLAGS: 00000286 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 0000000020001a40 RCX: 00000000004432fa
RDX: 0000000020001a00 RSI: 0000000020001a40 RDI: 00007ffda3d84550
RBP: 0000000000000000 R08: 0000000020001f00 R09: 000000000000000a
R10: 0000000000000000 R11: 0000000000000286 R12: 0000000000000003
R13: 0000000000000004 R14: 0000000000000000 R15: 0000000000000000
CPU: 1 PID: 4473 Comm: syzkaller533472 Not tainted 4.16.0+ #15
------------[ cut here ]------------
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+0x1a7/0x27d lib/dump_stack.c:53
kobject_add_internal failed for nodev( with -EEXIST, don't try to register  
things with the same name in the same directory.
  panic+0x1f8/0x42c kernel/panic.c:183
WARNING: CPU: 0 PID: 4474 at lib/kobject.c:238  
kobject_add_internal+0x8d4/0xbc0 lib/kobject.c:235
Modules linked in:
  __warn+0x1dc/0x200 kernel/panic.c:547
CPU: 0 PID: 4474 Comm: syzkaller533472 Not tainted 4.16.0+ #15
  report_bug+0x1f4/0x2b0 lib/bug.c:186
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS  
Google 01/01/2011
  fixup_bug.part.10+0x37/0x80 arch/x86/kernel/traps.c:178
RIP: 0010:kobject_add_internal+0x8d4/0xbc0 lib/kobject.c:235
  fixup_bug arch/x86/kernel/traps.c:247 [inline]
  do_error_trap+0x2d7/0x3e0 arch/x86/kernel/traps.c:296
RSP: 0000:ffff8801addaf470 EFLAGS: 00010282
RAX: dffffc0000000008 RBX: ffff8801d9661110 RCX: ffffffff815b5d2e
RDX: 0000000000000000 RSI: 1ffff10035bb5e3e RDI: 1ffff10035bb5e13
RBP: ffff8801addaf568 R08: 1ffff10035bb5dd5 R09: 0000000000000001
R10: 0000000000000001 R11: 0000000000000000 R12: 1ffff10035bb5e94
R13: 00000000ffffffef R14: ffff8801d39ae348 R15: 1ffff10035bb5e98
FS:  0000000001db2880(0000) GS:ffff8801db000000(0000) knlGS:0000000000000000
  do_invalid_op+0x1b/0x20 arch/x86/kernel/traps.c:315
  invalid_op+0x1b/0x40 arch/x86/entry/entry_64.S:991
RIP: 0010:kobject_add_internal+0x8d4/0xbc0 lib/kobject.c:235
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000019657b0 CR3: 00000001ae0ca000 CR4: 00000000001406f0
RSP: 0018:ffff8801ade37470 EFLAGS: 00010282
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
RAX: dffffc0000000008 RBX: ffff8801d9459190 RCX: ffffffff815b5d2e
Call Trace:
RDX: 0000000000000000 RSI: 1ffff10035bc6e3e RDI: 1ffff10035bc6e13
RBP: ffff8801ade37568 R08: 1ffff10035bc6dd5 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: 1ffff10035bc6e94
R13: 00000000ffffffef R14: ffff8801d39ae348 R15: 1ffff10035bc6e98
  kobject_add_varg lib/kobject.c:364 [inline]
  kobject_init_and_add+0xf9/0x150 lib/kobject.c:436
  gfs2_sys_fs_add+0x1ff/0x580 fs/gfs2/sys.c:652
  kobject_add_varg lib/kobject.c:364 [inline]
  kobject_init_and_add+0xf9/0x150 lib/kobject.c:436
  gfs2_sys_fs_add+0x1ff/0x580 fs/gfs2/sys.c:652
  fill_super+0x86f/0x1d70 fs/gfs2/ops_fstype.c:1118
  fill_super+0x86f/0x1d70 fs/gfs2/ops_fstype.c:1118
  gfs2_mount+0x587/0x6e0 fs/gfs2/ops_fstype.c:1321
  mount_fs+0x66/0x2d0 fs/super.c:1222
  vfs_kern_mount.part.26+0xc6/0x4a0 fs/namespace.c:1037
  gfs2_mount+0x587/0x6e0 fs/gfs2/ops_fstype.c:1321
  vfs_kern_mount fs/namespace.c:2514 [inline]
  do_new_mount fs/namespace.c:2517 [inline]
  do_mount+0xea4/0x2b90 fs/namespace.c:2847
  mount_fs+0x66/0x2d0 fs/super.c:1222
  vfs_kern_mount.part.26+0xc6/0x4a0 fs/namespace.c:1037
  vfs_kern_mount fs/namespace.c:2514 [inline]
  do_new_mount fs/namespace.c:2517 [inline]
  do_mount+0xea4/0x2b90 fs/namespace.c:2847
  ksys_mount+0xab/0x120 fs/namespace.c:3063
  SYSC_mount fs/namespace.c:3077 [inline]
  SyS_mount+0x39/0x50 fs/namespace.c:3074
  do_syscall_64+0x281/0x940 arch/x86/entry/common.c:287
  ksys_mount+0xab/0x120 fs/namespace.c:3063
  SYSC_mount fs/namespace.c:3077 [inline]
  SyS_mount+0x39/0x50 fs/namespace.c:3074
  do_syscall_64+0x281/0x940 arch/x86/entry/common.c:287
  entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x4432fa
RSP: 002b:00007ffda3d84538 EFLAGS: 00000286
  ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 0000000020001a40 RCX: 00000000004432fa
RDX: 0000000020001a00 RSI: 0000000020001a40 RDI: 00007ffda3d84550
RBP: 0000000000000000 R08: 0000000020001f00 R09: 000000000000000a
  entry_SYSCALL_64_after_hwframe+0x42/0xb7
R10: 0000000000000000 R11: 0000000000000286 R12: 0000000000000003
R13: 0000000000000004 R14: 0000000000000000 R15: 0000000000000000
RIP: 0033:0x4432fa
RSP: 002b:00007ffda3d84538 EFLAGS: 00000286
Code:
  ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 0000000020001a40 RCX: 00000000004432fa
00
RDX: 0000000020001a00 RSI: 0000000020001a40 RDI: 00007ffda3d84550
00
RBP: 0000000000000000 R08: 0000000020001f00 R09: 000000000000000a
00
R10: 0000000000000000 R11: 0000000000000286 R12: 0000000000000003
R13: 0000000000000004 R14: 0000000000000000 R15: 0000000000000000
00 fc ff df 48 c1 ea 03 80 3c 02 00 0f 85 aa 00 00 00 48 8b 13 48 c7 c6 80  
8b d6 87 48 c7 c7 e0 88 d6 87 e8 3c 33 58 fa <0f> 0b e9 1d fb ff ff e8 60  
4c 88 fa 0f 0b e9 29 fe ff ff e8 54
---[ end trace 5eab46a9e10a0c8a ]---
Dumping ftrace buffer:
    (ftrace buffer empty)
Kernel Offset: disabled
Rebooting in 86400 seconds..


---
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