memory leak in get_device_parent

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit:    35efb51e Merge tag 'ext4_for_linus_stable' of git://git.ke..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=16577182a00000
kernel config:  https://syzkaller.appspot.com/x/.config?x=61dd9e15a761691d
dashboard link: https://syzkaller.appspot.com/bug?extid=02e97e2ad931a981e568
compiler:       gcc (GCC) 9.0.0 20181231 (experimental)
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=12dd6b06a00000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=1128ae9aa00000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+02e97e2ad931a981e568@xxxxxxxxxxxxxxxxxxxxxxxxx

8.129630][ T6979] RDX: 0000000000000000 RSI: 00000000400455c8 RDI:  
0000000000000003
BUG: memory leak
unreferenced object 0xffff88812a7a6a80 (size 96):
  comm "syz-executor898", pid 6976, jiffies 4295010285 (age 25.620s)
  hex dump (first 32 bytes):
    88 e0 e8 83 ff ff ff ff 88 6a 7a 2a 81 88 ff ff  .........jz*....
    88 6a 7a 2a 81 88 ff ff 00 00 00 00 00 00 00 00  .jz*............
  backtrace:
    [<00000000b0c40ba3>] kmemleak_alloc_recursive  
include/linux/kmemleak.h:55 [inline]
    [<00000000b0c40ba3>] slab_post_alloc_hook mm/slab.h:439 [inline]
    [<00000000b0c40ba3>] slab_alloc mm/slab.c:3326 [inline]
    [<00000000b0c40ba3>] kmem_cache_alloc_trace+0x13d/0x280 mm/slab.c:3553
    [<00000000799c79a9>] kmalloc include/linux/slab.h:547 [inline]
    [<00000000799c79a9>] kzalloc include/linux/slab.h:742 [inline]
    [<00000000799c79a9>] class_dir_create_and_add drivers/base/core.c:1723  
[inline]
    [<00000000799c79a9>] get_device_parent.isra.0+0x1a8/0x240  
drivers/base/core.c:1787
    [<00000000b241fc22>] device_add+0x136/0x890 drivers/base/core.c:2048
    [<00000000ee099a63>] hci_register_dev+0x166/0x380  
net/bluetooth/hci_core.c:3305
    [<00000000c362a920>] hci_uart_register_dev  
drivers/bluetooth/hci_ldisc.c:676 [inline]
    [<00000000c362a920>] hci_uart_set_proto  
drivers/bluetooth/hci_ldisc.c:700 [inline]
    [<00000000c362a920>] hci_uart_tty_ioctl+0x221/0x350  
drivers/bluetooth/hci_ldisc.c:754
    [<00000000de259614>] tty_ioctl+0x6e2/0xa30 drivers/tty/tty_io.c:2664
    [<00000000f5bde6a4>] vfs_ioctl fs/ioctl.c:46 [inline]
    [<00000000f5bde6a4>] file_ioctl fs/ioctl.c:509 [inline]
    [<00000000f5bde6a4>] do_vfs_ioctl+0x62a/0x810 fs/ioctl.c:696
    [<0000000040a4c505>] ksys_ioctl+0x86/0xb0 fs/ioctl.c:713
    [<00000000e454fe0b>] __do_sys_ioctl fs/ioctl.c:720 [inline]
    [<00000000e454fe0b>] __se_sys_ioctl fs/ioctl.c:718 [inline]
    [<00000000e454fe0b>] __x64_sys_ioctl+0x1e/0x30 fs/ioctl.c:718
    [<00000000475478db>] do_syscall_64+0x76/0x1a0  
arch/x86/entry/common.c:301
    [<00000000708a3428>] entry_SYSCALL_64_after_hwframe+0x44/0xa9

BUG: memory leak
unreferenced object 0xffff88811893cf00 (size 96):
  comm "syz-executor898", pid 6978, jiffies 4295011473 (age 13.740s)
  hex dump (first 32 bytes):
    88 e0 e8 83 ff ff ff ff 08 cf 93 18 81 88 ff ff  ................
    08 cf 93 18 81 88 ff ff 00 00 00 00 00 00 00 00  ................
  backtrace:
    [<00000000b0c40ba3>] kmemleak_alloc_recursive  
include/linux/kmemleak.h:55 [inline]
    [<00000000b0c40ba3>] slab_post_alloc_hook mm/slab.h:439 [inline]
    [<00000000b0c40ba3>] slab_alloc mm/slab.c:3326 [inline]
    [<00000000b0c40ba3>] kmem_cache_alloc_trace+0x13d/0x280 mm/slab.c:3553
    [<00000000799c79a9>] kmalloc include/linux/slab.h:547 [inline]
    [<00000000799c79a9>] kzalloc include/linux/slab.h:742 [inline]
    [<00000000799c79a9>] class_dir_create_and_add drivers/base/core.c:1723  
[inline]
    [<00000000799c79a9>] get_device_parent.isra.0+0x1a8/0x240  
drivers/base/core.c:1787
    [<00000000b241fc22>] device_add+0x136/0x890 drivers/base/core.c:2048
    [<00000000ee099a63>] hci_register_dev+0x166/0x380  
net/bluetooth/hci_core.c:3305
    [<00000000c362a920>] hci_uart_register_dev  
drivers/bluetooth/hci_ldisc.c:676 [inline]
    [<00000000c362a920>] hci_uart_set_proto  
drivers/bluetooth/hci_ldisc.c:700 [inline]
    [<00000000c362a920>] hci_uart_tty_ioctl+0x221/0x350  
drivers/bluetooth/hci_ldisc.c:754
    [<00000000de259614>] tty_ioctl+0x6e2/0xa30 drivers/tty/tty_io.c:2664
    [<00000000f5bde6a4>] vfs_ioctl fs/ioctl.c:46 [inline]
    [<00000000f5bde6a4>] file_ioctl fs/ioctl.c:509 [inline]
    [<00000000f5bde6a4>] do_vfs_ioctl+0x62a/0x810 fs/ioctl.c:696
    [<0000000040a4c505>] ksys_ioctl+0x86/0xb0 fs/ioctl.c:713
    [<00000000e454fe0b>] __do_sys_ioctl fs/ioctl.c:720 [inline]
    [<00000000e454fe0b>] __se_sys_ioctl fs/ioctl.c:718 [inline]
    [<00000000e454fe0b>] __x64_sys_ioctl+0x1e/0x30 fs/ioctl.c:718
    [<00000000475478db>] do_syscall_64+0x76/0x1a0  
arch/x86/entry/common.c:301
    [<00000000708a3428>] entry_SYSCALL_64_after_hwframe+0x44/0xa9



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