The patch titled Subject: mm: fix apply_to_existing_page_range() has been added to the -mm mm-hotfixes-unstable branch. Its filename is mm-fix-apply_to_existing_page_range.patch
This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches...
This patch will later appear in the mm-hotfixes-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------ From: "Kirill A. Shutemov" kirill.shutemov@linux.intel.com Subject: mm: fix apply_to_existing_page_range() Date: Wed, 9 Apr 2025 12:40:43 +0300
In the case of apply_to_existing_page_range(), apply_to_pte_range() is reached with 'create' set to false. When !create, the loop over the PTE page table is broken.
apply_to_pte_range() will only move to the next PTE entry if 'create' is true or if the current entry is not pte_none().
This means that the user of apply_to_existing_page_range() will not have 'fn' called for any entries after the first pte_none() in the PTE page table.
Fix the loop logic in apply_to_pte_range().
There are no known runtime issues from this, but the fix is trivial enough for stable@ even without a known buggy user.
Link: https://lkml.kernel.org/r/20250409094043.1629234-1-kirill.shutemov@linux.int... Signed-off-by: Kirill A. Shutemov kirill.shutemov@linux.intel.com Fixes: be1db4753ee6 ("mm/memory.c: add apply_to_existing_page_range() helper") Cc: Daniel Axtens dja@axtens.net Cc: David Hildenbrand david@redhat.com Cc: Vlastimil Babka vbabka@suse.cz Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org ---
mm/memory.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
--- a/mm/memory.c~mm-fix-apply_to_existing_page_range +++ a/mm/memory.c @@ -2943,11 +2943,11 @@ static int apply_to_pte_range(struct mm_ if (fn) { do { if (create || !pte_none(ptep_get(pte))) { - err = fn(pte++, addr, data); + err = fn(pte, addr, data); if (err) break; } - } while (addr += PAGE_SIZE, addr != end); + } while (pte++, addr += PAGE_SIZE, addr != end); }
arch_leave_lazy_mmu_mode(); _
Patches currently in -mm which might be from kirill.shutemov@linux.intel.com are
mm-page_alloc-fix-deadlock-on-cpu_hotplug_lock-in-__accept_page.patch mm-fix-apply_to_existing_page_range.patch