In the Linux kernel, the following vulnerability has been resolved:
usb: roles: fix NULL pointer issue when put modules reference
In current design, usb role class driver will get usb_role_switch parents module reference after the user get usb_role_switch device and put the reference after the user put the usb_role_switch device. However, the parent device of usb_role_switch may be removed before the user put the usb_role_switch. If so, then, NULL pointer issue will be met when the user put the parent modules reference.
This will save the module pointer in structure of usb_role_switch. Then, we dont need to find module by iterating long relations.