usb: roles: fix NULL pointer issue when put module's reference

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: usb: roles: fix NULL pointer issue when put module's reference In current design, usb role class driver will get usb_role_switch parent's 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 module's reference. This will save the module pointer in structure of usb_role_switch. Then, we don't need to find module by iterating long relations.

References

• https://git.kernel.org/stable/c/e279bf8e51893e1fe160b3d8126ef2dd00f661e1
• https://git.kernel.org/stable/c/ef982fc41055fcebb361a92288d3225783d12913
• https://git.kernel.org/stable/c/0158216805ca7e498d07de38840d2732166ae5fa
• https://git.kernel.org/stable/c/4b45829440b1b208948b39cc71f77a37a2536734
• https://git.kernel.org/stable/c/01f82de440f2ab07c259b7573371e1c42e5565db
• https://git.kernel.org/stable/c/1c9be13846c0b2abc2480602f8ef421360e1ad9e