In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
mm\/percpu-km: fix bitmap overflow and accounting in pcpu_create_chunk()<\/p>\n
In pcpu_create_chunk(), nr_pages is the total contiguous backing
\nallocation, i.e., nr_units * pcpu_unit_pages, but pcpu_chunk_populated()
\nuses it to set chunk->populated, whose size is pcpu_unit_pages, bitmap.
\nSince bit N in chunk->populated means page offset N inside every unit is
\nbacked. When nr_units > 1, the function writes beyond chunk->populated.
\nFix it by using chunk->nr_pages.<\/p>\n
It also fixes the global pcpu_nr_empty_pop_pages accounting, since
\npcpu_balance_free() only iterates up to chunk->nr_pages.<\/p>\n
Commit a63d4ac4ab609 (“percpu: make percpu-km set chunk->populated bitmap
\nproperly”) introduced the bitmap overflow issue. Later, commit
\nb539b87fed37f (“percpu: implmeent pcpu_nr_empty_pop_pages and
\nchunk->nr_populated”) added pcpu_nr_empty_pop_pages and caused the
\naccounting issue.<\/p>\n","protected":false},"excerpt":{"rendered":"
In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
mm\/percpu-km: fix bitmap overflow and accounting in pcpu_create_chunk()<\/p>\n
In pcpu_create_chunk(), nr_pages is the total contiguous b<\/p>\n","protected":false},"template":"","meta":[],"categories":[],"tags":[],"class_list":["post-12359","vuln","type-vuln","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln\/12359","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=12359"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=12359"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=12359"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}