CVE-2024-40948

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> mm/page_table_check: fix crash on ZONE_DEVICE<br /> <br /> Not all pages may apply to pgtable check. One example is ZONE_DEVICE<br /> pages: they map PFNs directly, and they don&amp;#39;t allocate page_ext at all<br /> even if there&amp;#39;s struct page around. One may reference<br /> devm_memremap_pages().<br /> <br /> When both ZONE_DEVICE and page-table-check enabled, then try to map some<br /> dax memories, one can trigger kernel bug constantly now when the kernel<br /> was trying to inject some pfn maps on the dax device:<br /> <br /> kernel BUG at mm/page_table_check.c:55!<br /> <br /> While it&amp;#39;s pretty legal to use set_pxx_at() for ZONE_DEVICE pages for page<br /> fault resolutions, skip all the checks if page_ext doesn&amp;#39;t even exist in<br /> pgtable checker, which applies to ZONE_DEVICE but maybe more.