Date:   Sun, 16 Sep 2018 08:33:03 -0700
From:   syzbot <syzbot+db1637662f412ac0d556@...kaller.appspotmail.com>
To:     gregkh@...uxfoundation.org, linux-kernel@...r.kernel.org,
        syzkaller-bugs@...glegroups.com, tj@...nel.org
Subject: general protection fault in kernfs_add_one

Hello,

syzbot found the following crash on:

HEAD commit:    5e335542de83 Merge branch 'for-linus' of git://git.kernel...
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=13a1f2ae400000
kernel config:  https://syzkaller.appspot.com/x/.config?x=9917ff4b798e1a1e
dashboard link: https://syzkaller.appspot.com/bug?extid=db1637662f412ac0d556
compiler:       gcc (GCC) 8.0.1 20180413 (experimental)
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=10a66c11400000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=1346c771400000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+db1637662f412ac0d556@...kaller.appspotmail.com

kobject_add_internal failed for hci2 (error: -2 parent: bluetooth)
Bluetooth: Can't register HCI device
Bluetooth: Can't register HCI device
kasan: CONFIG_KASAN_INLINE enabled
kasan: GPF could be caused by NULL-ptr deref or user memory access
general protection fault: 0000 [#1] PREEMPT SMP KASAN
kobject: 'hci5' (00000000943cb5fb): kobject_cleanup, parent           (null)
CPU: 0 PID: 6716 Comm: syz-executor469 Not tainted 4.19.0-rc3+ #9
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS  
Google 01/01/2011
RIP: 0010:kernfs_add_one+0x342/0x4d0 fs/kernfs/dir.c:812
Code: 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 49 01 00 00 48 b8 00 00 00 00  
00 fc ff df 4d 8b 6d 70 49 8d 7d 08 48 89 fa 48 c1 ea 03 <0f> b6 04 02 84  
c0 74 08 3c 03 0f 8e 16 01 00 00 45 8b 6d 08 31 ff
kobject: 'rfkill1319' (00000000969d6091): kobject_uevent_env
RSP: 0018:ffff8801bc5df588 EFLAGS: 00010202
RAX: dffffc0000000000 RBX: ffff8801ba043380 RCX: ffffffff87bea6d7
RDX: 0000000000000001 RSI: ffffffff81f7f9ca RDI: 0000000000000008
RBP: ffff8801bc5df5d0 R08: fffffbfff12d121d R09: fffffbfff12d121c
R10: fffffbfff12d121c R11: ffffffff896890e7 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
FS:  0000000001901880(0000) GS:ffff8801dae00000(0000) knlGS:0000000000000000
kobject: 'rfkill1320' (000000000f2f7b02): kobject_add_internal:  
parent: 'hci4', set: 'devices'
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f5e5ce5a000 CR3: 00000001bb73b000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
kobject: 'hci5' (00000000943cb5fb): calling ktype release
  kernfs_create_dir_ns+0xf6/0x160 fs/kernfs/dir.c:1031
  sysfs_create_dir_ns+0x19b/0x340 fs/sysfs/dir.c:58
kobject: 'rfkill1319' (00000000969d6091): fill_kobj_path: path  
= '/devices/virtual/bluetooth/hci2/rfkill1319'
  create_dir lib/kobject.c:88 [inline]
  kobject_add_internal+0x440/0xb60 lib/kobject.c:247
kobject: 'hci5': free name
  kobject_add_varg lib/kobject.c:382 [inline]
  kobject_add+0x13f/0x1b0 lib/kobject.c:426
kobject: 'rfkill1320' (000000000f2f7b02): kobject_uevent_env
  device_add+0x3e2/0x17f0 drivers/base/core.c:1879
kobject: 'rfkill1320' (000000000f2f7b02): fill_kobj_path: path  
= '/devices/virtual/bluetooth/hci4/rfkill1320'
kobject: 'rfkill1319' (00000000969d6091): kobject_cleanup, parent            
(null)
  hci_register_dev+0x3e6/0xb80 net/bluetooth/hci_core.c:3196
kobject: 'rfkill1320' (000000000f2f7b02): kobject_uevent_env
  __vhci_create_device+0x2c1/0x580 drivers/bluetooth/hci_vhci.c:139
kobject: 'hci1' (000000005b9ca8c2): kobject_add_internal:  
parent: 'bluetooth', set: 'devices'
  vhci_create_device drivers/bluetooth/hci_vhci.c:163 [inline]
  vhci_get_user drivers/bluetooth/hci_vhci.c:219 [inline]
  vhci_write+0x2de/0x470 drivers/bluetooth/hci_vhci.c:299
  call_write_iter include/linux/fs.h:1807 [inline]
  new_sync_write fs/read_write.c:474 [inline]
  __vfs_write+0x6b8/0x9f0 fs/read_write.c:487
kobject: 'rfkill1319' (00000000969d6091): calling ktype release
kobject: 'rfkill1320' (000000000f2f7b02): fill_kobj_path: path  
= '/devices/virtual/bluetooth/hci4/rfkill1320'
  vfs_write+0x1fc/0x560 fs/read_write.c:549
  ksys_write+0x101/0x260 fs/read_write.c:598
kobject: 'hci1' (000000005b9ca8c2): kobject_uevent_env
  __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+0x1b9/0x820 arch/x86/entry/common.c:290
kobject: 'hci1' (000000005b9ca8c2): fill_kobj_path: path  
= '/devices/virtual/bluetooth/hci1'
kobject: 'rfkill1319': free name
  entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x440e49
Code: e8 ac e8 ff ff 48 83 c4 18 c3 0f 1f 80 00 00 00 00 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 0b 0a fc ff c3 66 2e 0f 1f 84 00 00 00 00
kobject: 'hci2' (00000000156e1c6f): kobject_uevent_env
RSP: 002b:00007fff32bcc918 EFLAGS: 00000213 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000440e49
RDX: 0000000000000002 RSI: 00000000200000c0 RDI: 0000000000000003
RBP: 0000000000000000 R08: 00000000004002c8 R09: 00000000004002c8
R10: 0000000001901880 R11: 0000000000000213 R12: 0000000000013465
kobject: 'rfkill1321' (00000000bd6cc24c): kobject_add_internal:  
parent: 'hci1', set: 'devices'
R13: 0000000000401d70 R14: 0000000000000000 R15: 0000000000000000
Modules linked in:
kobject: 'hci3' (00000000c8669077): kobject_add_internal:  
parent: 'bluetooth', set: 'devices'
kobject: 'hci2' (00000000156e1c6f): fill_kobj_path: path  
= '/devices/virtual/bluetooth/hci2'
kobject: 'hci5' (0000000076c884f7): kobject_add_internal:  
parent: 'bluetooth', set: 'devices'
kobject: 'hci2' (00000000156e1c6f): kobject_cleanup, parent           (null)
kobject: 'rfkill1321' (00000000bd6cc24c): kobject_uevent_env
kobject: 'hci2' (00000000156e1c6f): calling ktype release
kobject: 'hci5' (0000000076c884f7): kobject_uevent_env
kobject: 'hci2': free name
kobject: 'rfkill1321' (00000000bd6cc24c): fill_kobj_path: path  
= '/devices/virtual/bluetooth/hci1/rfkill1321'
---[ end trace 984285625d9f4992 ]---
kobject: 'hci5' (0000000076c884f7): fill_kobj_path: path  
= '/devices/virtual/bluetooth/hci5'
kobject: 'hci2' (0000000016287cb9): kobject_add_internal:  
parent: 'bluetooth', set: 'devices'
kobject: 'hci3' (00000000c8669077): kobject_uevent_env
RIP: 0010:kernfs_add_one+0x342/0x4d0 fs/kernfs/dir.c:812
kobject: 'hci3' (00000000c8669077): fill_kobj_path: path  
= '/devices/virtual/bluetooth/hci3'
kobject: 'hci2' (0000000016287cb9): kobject_uevent_env
kobject: 'rfkill1320' (000000000f2f7b02): kobject_cleanup, parent            
(null)
kobject: 'hci2' (0000000016287cb9): fill_kobj_path: path  
= '/devices/virtual/bluetooth/hci2'
kobject: 'rfkill1321' (00000000bd6cc24c): kobject_uevent_env
Code: 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 49 01 00 00 48 b8 00 00 00 00  
00 fc ff df 4d 8b 6d 70 49 8d 7d 08 48 89 fa 48 c1 ea 03 <0f> b6 04 02 84  
c0 74 08 3c 03 0f 8e 16 01 00 00 45 8b 6d 08 31 ff
kobject: 'rfkill1322' (00000000876a5655): kobject_add_internal:  
parent: 'hci5', set: 'devices'
RSP: 0018:ffff8801bc5df588 EFLAGS: 00010202
kobject: 'rfkill1321' (00000000bd6cc24c): fill_kobj_path: path  
= '/devices/virtual/bluetooth/hci1/rfkill1321'
kobject: 'rfkill1320' (000000000f2f7b02): calling ktype release
RAX: dffffc0000000000 RBX: ffff8801ba043380 RCX: ffffffff87bea6d7
kobject: 'rfkill1322' (00000000876a5655): kobject_uevent_env
RDX: 0000000000000001 RSI: ffffffff81f7f9ca RDI: 0000000000000008
kobject: 'rfkill1320': free name
kobject: 'rfkill1322' (00000000876a5655): fill_kobj_path: path  
= '/devices/virtual/bluetooth/hci5/rfkill1322'
kobject: 'hci4' (0000000004abaebf): kobject_uevent_env
RBP: ffff8801bc5df5d0 R08: fffffbfff12d121d R09: fffffbfff12d121c
kobject: 'hci4' (0000000004abaebf): fill_kobj_path: path  
= '/devices/virtual/bluetooth/hci4'
R10: fffffbfff12d121c R11: ffffffff896890e7 R12: 0000000000000000
kobject: 'hci4' (0000000004abaebf): kobject_cleanup, parent           (null)
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
kobject: 'rfkill1322' (00000000876a5655): kobject_uevent_env
FS:  0000000001901880(0000) GS:ffff8801daf00000(0000) knlGS:0000000000000000
kobject: 'rfkill1322' (00000000876a5655): fill_kobj_path: path  
= '/devices/virtual/bluetooth/hci5/rfkill1322'
kobject: 'rfkill1323' (000000001d9583a0): kobject_add_internal:  
parent: 'hci2', set: 'devices'
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
kobject: 'rfkill1323' (000000001d9583a0): kobject_uevent_env
CR2: 00007f5e5ce5a000 CR3: 00000001bb73b000 CR4: 00000000001406e0
kobject: 'hci4' (0000000004abaebf): calling ktype release
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
kobject: 'rfkill1323' (000000001d9583a0): fill_kobj_path: path  
= '/devices/virtual/bluetooth/hci2/rfkill1323'
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
kobject: 'hci4': free name


---
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