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 (cherry picked from commit a995199384347261bb3f21b2e171fa7f988bd2f8) Signed-off-by: Kirill A. Shutemov kirill.shutemov@linux.intel.com --- mm/memory.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/mm/memory.c b/mm/memory.c index 62fe3707ff92..4998b4c49052 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -2570,11 +2570,11 @@ static int apply_to_pte_range(struct mm_struct *mm, pmd_t *pmd, if (fn) { do { if (create || !pte_none(*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); } *mask |= PGTBL_PTE_MODIFIED;