The quilt patch titled Subject: mm: kfence: fix handling discontiguous page has been removed from the -mm tree. Its filename was mm-kfence-fix-handling-discontiguous-page.patch

This patch was dropped because it was merged into the mm-hotfixes-stable branch of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

------------------------------------------------------ From: Muchun Song songmuchun@bytedance.com Subject: mm: kfence: fix handling discontiguous page Date: Thu, 23 Mar 2023 10:50:03 +0800

The struct pages could be discontiguous when the kfence pool is allocated via alloc_contig_pages() with CONFIG_SPARSEMEM and !CONFIG_SPARSEMEM_VMEMMAP.

This may result in setting PG_slab and memcg_data to a arbitrary address (may be not used as a struct page), which in the worst case might corrupt the kernel.

So the iteration should use nth_page().

Link: https://lkml.kernel.org/r/20230323025003.94447-1-songmuchun@bytedance.com Fixes: 0ce20dd84089 ("mm: add Kernel Electric-Fence infrastructure") Signed-off-by: Muchun Song songmuchun@bytedance.com Reviewed-by: Marco Elver elver@google.com Reviewed-by: Kefeng Wang wangkefeng.wang@huawei.com Cc: Alexander Potapenko glider@google.com Cc: Dmitry Vyukov dvyukov@google.com Cc: Jann Horn jannh@google.com Cc: SeongJae Park sjpark@amazon.de Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org ---

mm/kfence/core.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/mm/kfence/core.c~mm-kfence-fix-handling-discontiguous-page +++ a/mm/kfence/core.c @@ -556,7 +556,7 @@ static unsigned long kfence_init_pool(vo * enters __slab_free() slow-path. */ for (i = 0; i < KFENCE_POOL_SIZE / PAGE_SIZE; i++) { - struct slab *slab = page_slab(&pages[i]); + struct slab *slab = page_slab(nth_page(pages, i));

if (!i || (i % 2)) continue; @@ -602,7 +602,7 @@ static unsigned long kfence_init_pool(vo

reset_slab: for (i = 0; i < KFENCE_POOL_SIZE / PAGE_SIZE; i++) { - struct slab *slab = page_slab(&pages[i]); + struct slab *slab = page_slab(nth_page(pages, i));

if (!i || (i % 2)) continue; _

Patches currently in -mm which might be from songmuchun@bytedance.com are

mm-hugetlb_vmemmap-simplify-hugetlb_vmemmap_init-a-bit.patch