Merge tag 'mm-hotfixes-stable-2022-10-11' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull misc hotfixes from Andrew Morton:
 "Five hotfixes - three for nilfs2, two for MM. For are cc:stable, one
  is not"

* tag 'mm-hotfixes-stable-2022-10-11' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm:
  nilfs2: fix leak of nilfs_root in case of writer thread creation failure
  nilfs2: fix NULL pointer dereference at nilfs_bmap_lookup_at_level()
  nilfs2: fix use-after-free bug of struct nilfs_root
  mm/damon/core: initialize damon_target->list in damon_new_target()
  mm/hugetlb: fix races when looking up a CONT-PTE/PMD size hugetlb page

3 files changed, 27 insertions, 15 deletions

diff --git a/mm/damon/core.c b/mm/damon/core.c
index 4de8c7c52979..8e1ab38d0f1f 100644
--- a/mm/damon/core.c
+++ b/mm/damon/core.c
@@ -335,6 +335,7 @@ struct damon_target *damon_new_target(void)
 	t->pid = NULL;
 	t->nr_regions = 0;
 	INIT_LIST_HEAD(&t->regions_list);
+	INIT_LIST_HEAD(&t->list);
 
 	return t;
 }
diff --git a/mm/gup.c b/mm/gup.c
index ce00a4c40da8..fe195d47de74 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -537,6 +537,18 @@ static struct page *follow_page_pte(struct vm_area_struct *vma,
 	if (WARN_ON_ONCE((flags & (FOLL_PIN | FOLL_GET)) ==
 			 (FOLL_PIN | FOLL_GET)))
 		return ERR_PTR(-EINVAL);
+
+	/*
+	 * Considering PTE level hugetlb, like continuous-PTE hugetlb on
+	 * ARM64 architecture.
+	 */
+	if (is_vm_hugetlb_page(vma)) {
+		page = follow_huge_pmd_pte(vma, address, flags);
+		if (page)
+			return page;
+		return no_page_table(vma, flags);
+	}
+
 retry:
 	if (unlikely(pmd_bad(*pmd)))
 		return no_page_table(vma, flags);
@@ -669,7 +681,7 @@ static struct page *follow_pmd_mask(struct vm_area_struct *vma,
 	if (pmd_none(pmdval))
 		return no_page_table(vma, flags);
 	if (pmd_huge(pmdval) && is_vm_hugetlb_page(vma)) {
-		page = follow_huge_pmd(mm, address, pmd, flags);
+		page = follow_huge_pmd_pte(vma, address, flags);
 		if (page)
 			return page;
 		return no_page_table(vma, flags);
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 0ad53ad98e74..57b7b0b5d9eb 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -7150,12 +7150,13 @@ follow_huge_pd(struct vm_area_struct *vma,
 }
 
 struct page * __weak
-follow_huge_pmd(struct mm_struct *mm, unsigned long address,
-		pmd_t *pmd, int flags)
+follow_huge_pmd_pte(struct vm_area_struct *vma, unsigned long address, int flags)
 {
+	struct hstate *h = hstate_vma(vma);
+	struct mm_struct *mm = vma->vm_mm;
 	struct page *page = NULL;
 	spinlock_t *ptl;
-	pte_t pte;
+	pte_t *ptep, pte;
 
 	/*
 	 * FOLL_PIN is not supported for follow_page(). Ordinary GUP goes via
@@ -7165,17 +7166,15 @@ follow_huge_pmd(struct mm_struct *mm, unsigned long address,
 		return NULL;
 
 retry:
-	ptl = pmd_lockptr(mm, pmd);
-	spin_lock(ptl);
-	/*
-	 * make sure that the address range covered by this pmd is not
-	 * unmapped from other threads.
-	 */
-	if (!pmd_huge(*pmd))
-		goto out;
-	pte = huge_ptep_get((pte_t *)pmd);
+	ptep = huge_pte_offset(mm, address, huge_page_size(h));
+	if (!ptep)
+		return NULL;
+
+	ptl = huge_pte_lock(h, mm, ptep);
+	pte = huge_ptep_get(ptep);
 	if (pte_present(pte)) {
-		page = pmd_page(*pmd) + ((address & ~PMD_MASK) >> PAGE_SHIFT);
+		page = pte_page(pte) +
+			((address & ~huge_page_mask(h)) >> PAGE_SHIFT);
 		/*
 		 * try_grab_page() should always succeed here, because: a) we
 		 * hold the pmd (ptl) lock, and b) we've just checked that the
@@ -7191,7 +7190,7 @@ retry:
 	} else {
 		if (is_hugetlb_entry_migration(pte)) {
 			spin_unlock(ptl);
-			__migration_entry_wait_huge((pte_t *)pmd, ptl);
+			__migration_entry_wait_huge(ptep, ptl);
 			goto retry;
 		}
 		/*