memory leak in hci_conn_add

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    47ec5303 Merge git://git.kernel.org/pub/scm/linux/kernel/g..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=11a0122c900000
kernel config:  https://syzkaller.appspot.com/x/.config?x=eab224ce244e423c
dashboard link: https://syzkaller.appspot.com/bug?extid=52b86f9cc3cda3b318e0
compiler:       gcc (GCC) 10.1.0-syz 20200507
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=118774aa900000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+52b86f9cc3cda3b318e0@xxxxxxxxxxxxxxxxxxxxxxxxx

2020/08/07 02:25:22 executed programs: 153
BUG: memory leak
unreferenced object 0xffff88811aef9800 (size 2048):
  comm "syz-executor.0", pid 7170, jiffies 4295036619 (age 51.850s)
  hex dump (first 32 bytes):
    00 40 3d 15 81 88 ff ff 22 01 00 00 00 00 ad de  .@=.....".......
    00 00 00 00 11 aa aa aa aa aa 00 aa aa aa aa aa  ................
  backtrace:
    [<00000000d9c20f00>] kmalloc include/linux/slab.h:555 [inline]
    [<00000000d9c20f00>] kzalloc include/linux/slab.h:669 [inline]
    [<00000000d9c20f00>] hci_conn_add+0x2e/0x4a0 net/bluetooth/hci_conn.c:525
    [<0000000035c3df04>] hci_connect_acl net/bluetooth/hci_conn.c:1252 [inline]
    [<0000000035c3df04>] hci_connect_acl+0x154/0x170 net/bluetooth/hci_conn.c:1237
    [<0000000084224e06>] l2cap_chan_connect+0x2bb/0xbb0 net/bluetooth/l2cap_core.c:7900
    [<000000008efaf6d0>] bt_6lowpan_connect net/bluetooth/6lowpan.c:932 [inline]
    [<000000008efaf6d0>] lowpan_control_write+0x2fb/0x380 net/bluetooth/6lowpan.c:1166
    [<00000000d92efe51>] full_proxy_write+0x61/0x90 fs/debugfs/file.c:234
    [<000000007171039b>] vfs_write+0xfa/0x250 fs/read_write.c:576
    [<000000006150b244>] ksys_write+0x72/0x120 fs/read_write.c:631
    [<00000000c631a395>] do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
    [<00000000f2b9f07c>] entry_SYSCALL_64_after_hwframe+0x44/0xa9

BUG: memory leak
unreferenced object 0xffff88811c49f200 (size 512):
  comm "syz-executor.0", pid 7170, jiffies 4295036619 (age 51.850s)
  hex dump (first 32 bytes):
    00 98 ef 1a 81 88 ff ff c0 9a 3e 15 81 88 ff ff  ..........>.....
    fd 03 00 00 00 00 00 00 00 06 00 00 00 00 00 00  ................
  backtrace:
    [<000000003ade7b37>] kmalloc include/linux/slab.h:555 [inline]
    [<000000003ade7b37>] kzalloc include/linux/slab.h:669 [inline]
    [<000000003ade7b37>] l2cap_conn_add.part.0+0x3b/0x300 net/bluetooth/l2cap_core.c:7702
    [<00000000c0f3ada8>] l2cap_conn_add net/bluetooth/l2cap_core.c:7888 [inline]
    [<00000000c0f3ada8>] l2cap_chan_connect+0x742/0xbb0 net/bluetooth/l2cap_core.c:7909
    [<000000008efaf6d0>] bt_6lowpan_connect net/bluetooth/6lowpan.c:932 [inline]
    [<000000008efaf6d0>] lowpan_control_write+0x2fb/0x380 net/bluetooth/6lowpan.c:1166
    [<00000000d92efe51>] full_proxy_write+0x61/0x90 fs/debugfs/file.c:234
    [<000000007171039b>] vfs_write+0xfa/0x250 fs/read_write.c:576
    [<000000006150b244>] ksys_write+0x72/0x120 fs/read_write.c:631
    [<00000000c631a395>] do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
    [<00000000f2b9f07c>] entry_SYSCALL_64_after_hwframe+0x44/0xa9



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