From: Andrew Bresticker <abrestic@rivosinc.com> next inclusion category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/IA7H2V CVE: NA Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... -------------------------------- The requirement that the head page be passed to do_set_pmd() was added in commit ef37b2ea08ac ("mm/memory: page_add_file_rmap() -> folio_add_file_rmap_[pte|pmd]()") and prevents pmd-mapping in the finish_fault() and filemap_map_pages() paths if the page to be inserted is anything but the head page for an otherwise suitable vma and pmd-sized page. Matthew said: : We're going to stop using PMDs to map large folios unless the fault is : within the first 4KiB of the PMD. No idea how many workloads that : affects, but it only needs to be backported as far as v6.8, so we may : as well backport it. Link: https://lkml.kernel.org/r/20240611153216.2794513-1-abrestic@rivosinc.com Fixes: ef37b2ea08ac ("mm/memory: page_add_file_rmap() -> folio_add_file_rmap_[pte|pmd]()") Signed-off-by: Andrew Bresticker <abrestic@rivosinc.com> Acked-by: David Hildenbrand <david@redhat.com> Acked-by: Hugh Dickins <hughd@google.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Liu Shixin <liushixin2@huawei.com> --- mm/memory.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/mm/memory.c b/mm/memory.c index 83c3650b533b..fe10342687d0 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -4609,8 +4609,9 @@ vm_fault_t do_set_pmd(struct vm_fault *vmf, struct page *page) if (!thp_vma_suitable_order(vma, haddr, PMD_ORDER)) return ret; - if (page != &folio->page || folio_order(folio) != HPAGE_PMD_ORDER) + if (folio_order(folio) != HPAGE_PMD_ORDER) return ret; + page = &folio->page; /* * Just backoff if any subpage of a THP is corrupted otherwise -- 2.25.1