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.
https://git.kernel.org/stable/c/a4b46d450c49f32e9d4247b421e58083fde304ce
https://git.kernel.org/stable/c/63533549ff53d24daf47c443dbd43c308afc3434
https://git.kernel.org/stable/c/6119ef6517ce501fc548154691abdaf1f954a277
https://git.kernel.org/stable/c/5f1d68ef5ddac27c6b997adccd1c339cef1e6848