CVE-2024-36896

In the Linux kernel, the following vulnerability has been resolved: USB:
core: Fix access violation during port device removal Testing with KASAN
and syzkaller revealed a bug in port.c:disable_store():
usb_hub_to_struct_hub() can return NULL if the hub that the port belongs to
is concurrently removed, but the function does not check for this
possibility before dereferencing the returned value. It turns out that the
first dereference is unnecessary, since hub->intfdev is the parent of the
port device, so it can be changed easily. Adding a check for hub == NULL
prevents further problems. The same bug exists in the disable_show()
routine, and it can be fixed the same way.