CVE-2024-56612 mm/gup: handle NULL pages in unpin_user_pages()

In the Linux kernel, the following vulnerability has been resolved: mm/gup: handle NULL pages in unpinuserpages The recent addition of "pofs" pages or folios handling to gup has a flaw: it assumes that unpinuserpages handles NULL pages in the pages array. That's not the case, as I discovered when...