CVE-2026-64302

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> x86/mm: Fix freeing of PMD-sized vmemmap pages<br /> <br /> Commit bf9e4e30f353 ("x86/mm: use pagetable_free()"), switched from<br /> freeing non-boot page tables through __free_pages() to<br /> pagetable_free().<br /> <br /> However, the function is also called to free vmemmap pages.<br /> <br /> Given that vmemmap pages are not page tables, already the page_ptdesc(page)<br /> is wrong. But worse, pagetable_free() calls:<br /> <br /> __free_pages(page, compound_order(page));<br /> <br /> Since vmemmap pages are not compound pages (see vmemmap_alloc_block())<br /> -- except for HVO, which doesn&amp;#39;t apply here -- only first page of a<br /> PMD-sized vmemmap page is freed, leaking the other ones.<br /> <br /> Fix it by properly decoupling pagetable and vmemmap freeing.<br /> free_pagetable() no longer has to mess with SECTION_INFO, as only the<br /> vmemmap is marked like that in register_page_bootmem_memmap().<br /> <br /> The indentation in remove_pmd_table() is messed up. Fix that while<br /> touching it.<br /> <br /> Bootmem info handling will soon be fixed up. For now, handle it<br /> similar to free_pagetable(), just avoiding the ifdef.<br /> <br /> [ dhansen: changelog munging. More imperative voice ]