In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
powerpc\/mm: fix wrong addr_pfn tracking in compound vmemmap population<\/p>\n
vmemmap_populate_compound_pages() uses addr_pfn to determine the PFN
\noffset within a compound page and to decide whether the current vmemmap
\nslot should be populated as a head page mapping or should reuse a tail
\npage mapping.<\/p>\n
However, addr_pfn is advanced manually in parallel with addr. The loop
\nitself progresses in vmemmap address space, so each PAGE_SIZE step in addr
\ncovers PAGE_SIZE \/ sizeof(struct page) struct page slots. Since addr_pfn
\nis compared against nr_pages in data-PFN units, it should advance by the
\nsame number of PFNs. The existing manual increments do not match that and
\ntherefore do not reliably track the PFN corresponding to the current addr.<\/p>\n
As a result, pfn_offset can be computed from the wrong PFN and the code
\ncan make the head\/tail decision for the wrong compound-page position.<\/p>\n
Fix this by deriving addr_pfn directly from the current vmemmap address
\ninstead of carrying it as loop state.<\/p>\n","protected":false},"excerpt":{"rendered":"
In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
powerpc\/mm: fix wrong addr_pfn tracking in compound vmemmap population<\/p>\n
vmemmap_populate_compound_pages() uses addr_pfn to determin<\/p>\n","protected":false},"template":"","meta":[],"categories":[],"tags":[],"class_list":["post-24648","vuln","type-vuln","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln\/24648","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln"}],"about":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/types\/vuln"}],"wp:attachment":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=24648"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=24648"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=24648"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}