Hello Baolin Wang,
The patch 86522923bb29: "mm/damon: add access checking for hugetlb
pages" from Dec 30, 2021, leads to the following Smatch static
checker warning:
mm/damon/vaddr.c:405 damon_hugetlb_mkold()
warn: 'page' can't be NULL.
mm/damon/vaddr.c
398 static void damon_hugetlb_mkold(pte_t *pte, struct mm_struct *mm,
399 struct vm_area_struct *vma, unsigned long addr)
400 {
401 bool referenced = false;
402 pte_t entry = huge_ptep_get(pte);
403 struct page *page = pte_page(entry);
404
--> 405 if (!page)
I don't think it makes sense to check "page" because we're already dead
if pte_page() starts returning NULL. Maybe check "entry"?
406 return;
407
408 get_page(page);
409
410 if (pte_young(entry)) {
411 referenced = true;
412 entry = pte_mkold(entry);
413 huge_ptep_set_access_flags(vma, addr, pte, entry,
414 vma->vm_flags & VM_WRITE);
415 }
regards,
dan carpenter
