KASAN: use-after-free Read in vhci_hub_control

[syzbot <syzbot+600b03e0cf1b73bb23c4@syzkaller.appspotmail.com>]

Hello,

syzbot found the following crash on:

HEAD commit:    420f51f4ab6b Merge tag 'arm64-fixes' of git://git.kernel.o..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=160cf55a400000
kernel config:  https://syzkaller.appspot.com/x/.config?x=531a917630d2a492
dashboard link: https://syzkaller.appspot.com/bug?extid=600b03e0cf1b73bb23c4
compiler:       gcc (GCC) 8.0.1 20180413 (experimental)
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=1116710a400000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=119be4ea400000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+600b03e0cf1b73bb23c4@syzkaller.appspotmail.com

random: sshd: uninitialized urandom read (32 bytes read)
random: sshd: uninitialized urandom read (32 bytes read)
random: sshd: uninitialized urandom read (32 bytes read)
vhci_hcd: invalid port number 108
==================================================================
BUG: KASAN: use-after-free in vhci_hub_control+0x1b88/0x1bf0  
drivers/usb/usbip/vhci_hcd.c:441
Read of size 4 at addr ffff8801ce61f7bc by task syz-executor473/4680

CPU: 1 PID: 4680 Comm: syz-executor473 Not tainted 4.19.0-rc1+ #217
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS  
Google 01/01/2011
Call Trace:
  __dump_stack lib/dump_stack.c:77 [inline]
  dump_stack+0x1c9/0x2b4 lib/dump_stack.c:113
  print_address_description+0x6c/0x20b mm/kasan/report.c:256
  kasan_report_error mm/kasan/report.c:354 [inline]
  kasan_report.cold.7+0x242/0x30d mm/kasan/report.c:412
  __asan_report_load4_noabort+0x14/0x20 mm/kasan/report.c:432
  vhci_hub_control+0x1b88/0x1bf0 drivers/usb/usbip/vhci_hcd.c:441
  rh_call_control drivers/usb/core/hcd.c:679 [inline]
  rh_urb_enqueue drivers/usb/core/hcd.c:838 [inline]
  usb_hcd_submit_urb+0x184a/0x2160 drivers/usb/core/hcd.c:1651
  usb_submit_urb+0x895/0x14d0 drivers/usb/core/urb.c:570
  usb_start_wait_urb+0x140/0x360 drivers/usb/core/message.c:57
  usb_internal_control_msg drivers/usb/core/message.c:101 [inline]
  usb_control_msg+0x332/0x4e0 drivers/usb/core/message.c:152
  proc_control+0x99b/0xef0 drivers/usb/core/devio.c:1106
  usbdev_do_ioctl+0x1eb4/0x3b30 drivers/usb/core/devio.c:2394
  usbdev_ioctl+0x25/0x30 drivers/usb/core/devio.c:2551
  vfs_ioctl fs/ioctl.c:46 [inline]
  file_ioctl fs/ioctl.c:501 [inline]
  do_vfs_ioctl+0x1de/0x1720 fs/ioctl.c:685
  ksys_ioctl+0xa9/0xd0 fs/ioctl.c:702
  __do_sys_ioctl fs/ioctl.c:709 [inline]
  __se_sys_ioctl fs/ioctl.c:707 [inline]
  __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:707
  do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
  entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x445cf9
Code: e8 0c ad 02 00 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 db ce fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fff4cea17d8 EFLAGS: 00000213 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000445cf9
RDX: 0000000020000000 RSI: 00000000c0185500 RDI: 0000000000000003
RBP: 0000000000000000 R08: 0000000000fb6880 R09: 0000000000000001
R10: 000000000000000f R11: 0000000000000213 R12: 0000000000403060
R13: 00000000004030f0 R14: 0000000000000000 R15: 0000000000000000

The buggy address belongs to the page:
page:ffffea00073987c0 count:0 mapcount:0 mapping:0000000000000000 index:0x0
flags: 0x2fffc0000000000()
raw: 02fffc0000000000 0000000000000000 ffffffff07390101 0000000000000000
raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
  ffff8801ce61f680: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
  ffff8801ce61f700: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
> ffff8801ce61f780: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                                         ^
  ffff8801ce61f800: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
  ffff8801ce61f880: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================


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