From: David Hildenbrand david@redhat.com
mainline inclusion from mainline-v6.9-rc1 commit 23ed190868a65525b8941370630fbb215f12ebe8 category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/I9CHB4 CVE: NA
-------------------------------------------------
Let's prepare for further changes.
Link: https://lkml.kernel.org/r/20240129124649.189745-12-david@redhat.com Signed-off-by: David Hildenbrand david@redhat.com Reviewed-by: Ryan Roberts ryan.roberts@arm.com Reviewed-by: Mike Rapoport (IBM) rppt@kernel.org Cc: Albert Ou aou@eecs.berkeley.edu Cc: Alexander Gordeev agordeev@linux.ibm.com Cc: Alexandre Ghiti alexghiti@rivosinc.com Cc: Aneesh Kumar K.V aneesh.kumar@kernel.org Cc: Catalin Marinas catalin.marinas@arm.com Cc: Christian Borntraeger borntraeger@linux.ibm.com Cc: Christophe Leroy christophe.leroy@csgroup.eu Cc: David S. Miller davem@davemloft.net Cc: Dinh Nguyen dinguyen@kernel.org Cc: Gerald Schaefer gerald.schaefer@linux.ibm.com Cc: Heiko Carstens hca@linux.ibm.com Cc: Matthew Wilcox willy@infradead.org Cc: Michael Ellerman mpe@ellerman.id.au Cc: Naveen N. Rao naveen.n.rao@linux.ibm.com Cc: Nicholas Piggin npiggin@gmail.com Cc: Palmer Dabbelt palmer@dabbelt.com Cc: Paul Walmsley paul.walmsley@sifive.com Cc: Russell King (Oracle) linux@armlinux.org.uk Cc: Sven Schnelle svens@linux.ibm.com Cc: Vasily Gorbik gor@linux.ibm.com Cc: Will Deacon will@kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org (cherry picked from commit 23ed190868a65525b8941370630fbb215f12ebe8) Signed-off-by: Kefeng Wang wangkefeng.wang@huawei.com --- mm/memory.c | 63 ++++++++++++++++++++++++++++------------------------- 1 file changed, 33 insertions(+), 30 deletions(-)
diff --git a/mm/memory.c b/mm/memory.c index e7a959688bdc..7f1bd12589e7 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -935,6 +935,29 @@ copy_present_page(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma return 0; }
+static inline void __copy_present_pte(struct vm_area_struct *dst_vma, + struct vm_area_struct *src_vma, pte_t *dst_pte, pte_t *src_pte, + pte_t pte, unsigned long addr) +{ + struct mm_struct *src_mm = src_vma->vm_mm; + + /* If it's a COW mapping, write protect it both processes. */ + if (is_cow_mapping(src_vma->vm_flags) && pte_write(pte)) { + ptep_set_wrprotect(src_mm, addr, src_pte); + pte = pte_wrprotect(pte); + } + + /* If it's a shared mapping, mark it clean in the child. */ + if (src_vma->vm_flags & VM_SHARED) + pte = pte_mkclean(pte); + pte = pte_mkold(pte); + + if (!userfaultfd_wp(dst_vma)) + pte = pte_clear_uffd_wp(pte); + + set_pte_at(dst_vma->vm_mm, addr, dst_pte, pte); +} + /* * Copy one pte. Returns 0 if succeeded, or -EAGAIN if one preallocated page * is required to copy this pte. @@ -944,23 +967,23 @@ copy_present_pte(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma, pte_t *dst_pte, pte_t *src_pte, unsigned long addr, int *rss, struct folio **prealloc) { - struct mm_struct *src_mm = src_vma->vm_mm; - unsigned long vm_flags = src_vma->vm_flags; pte_t pte = ptep_get(src_pte); struct page *page; struct folio *folio;
page = vm_normal_page(src_vma, addr, pte); - if (page) - folio = page_folio(page); - if (page && folio_test_anon(folio)) { + if (unlikely(!page)) + goto copy_pte; + + folio = page_folio(page); + folio_get(folio); + if (folio_test_anon(folio)) { /* * If this page may have been pinned by the parent process, * copy the page immediately for the child so that we'll always * guarantee the pinned page won't be randomly replaced in the * future. */ - folio_get(folio); if (unlikely(folio_try_dup_anon_rmap_pte(folio, page, src_vma))) { /* Page may be pinned, we have to copy. */ folio_put(folio); @@ -968,35 +991,15 @@ copy_present_pte(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma, addr, rss, prealloc, page); } rss[MM_ANONPAGES]++; - } else if (page) { - folio_get(folio); + VM_WARN_ON_FOLIO(PageAnonExclusive(page), folio); + } else { folio_dup_file_rmap_pte(folio, page); rss[mm_counter_file(folio)]++; add_reliable_folio_counter(folio, dst_vma->vm_mm, 1); }
- /* - * If it's a COW mapping, write protect it both - * in the parent and the child - */ - if (is_cow_mapping(vm_flags) && pte_write(pte)) { - ptep_set_wrprotect(src_mm, addr, src_pte); - pte = pte_wrprotect(pte); - } - VM_BUG_ON(page && folio_test_anon(folio) && PageAnonExclusive(page)); - - /* - * If it's a shared mapping, mark it clean in - * the child - */ - if (vm_flags & VM_SHARED) - pte = pte_mkclean(pte); - pte = pte_mkold(pte); - - if (!userfaultfd_wp(dst_vma)) - pte = pte_clear_uffd_wp(pte); - - set_pte_at(dst_vma->vm_mm, addr, dst_pte, pte); +copy_pte: + __copy_present_pte(dst_vma, src_vma, dst_pte, src_pte, pte, addr); return 0; }