CVE-2026-89735

In the Linux kernel, the following vulnerability has been resolved:

usb: gadget: midi2: remove default configfs groups on teardown

f midi2 alloc inst() creates default configfs child groups for the default endpoint and default block using configfs add default group(), setting their internal refcount to 1.

However, during function teardown in f midi2 free inst() or EP cleanup in f midi2 ep opts release(), configfs remove default groups() is never called, therefore never dropping the refcount and leaking struct f midi2 ep opts and f midi2 block opts.

Add the missing configfs remove default groups() in the afformentioned functions to free the structs properly.