diff --git a/mm/gup.c b/mm/gup.c
index 70d65e4015a4..e95b0cb6ed81 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -143,6 +143,10 @@ retry:
 		mark_page_accessed(page);
 	}
 	if ((flags & FOLL_MLOCK) && (vma->vm_flags & VM_LOCKED)) {
+		/* Do not mlock pte-mapped THP */
+		if (PageTransCompound(page))
+			goto out;
+
 		/*
 		 * The preliminary mapping check is mainly to avoid the
 		 * pointless overhead of lock_page on the ZERO_PAGE
@@ -920,8 +924,6 @@ long populate_vma_page_range(struct vm_area_struct *vma,
 	gup_flags = FOLL_TOUCH | FOLL_POPULATE | FOLL_MLOCK;
 	if (vma->vm_flags & VM_LOCKONFAULT)
 		gup_flags &= ~FOLL_POPULATE;
-	if (vma->vm_flags & VM_LOCKED)
-		gup_flags |= FOLL_SPLIT;
 	/*
 	 * We want to touch writable mappings with a write fault in order
 	 * to break COW, except for shared mappings because these don't COW
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 4acf55b31f7c..f283cb7c480e 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -874,8 +874,6 @@ int do_huge_pmd_anonymous_page(struct mm_struct *mm, struct vm_area_struct *vma,
 
 	if (haddr < vma->vm_start || haddr + HPAGE_PMD_SIZE > vma->vm_end)
 		return VM_FAULT_FALLBACK;
-	if (vma->vm_flags & VM_LOCKED)
-		return VM_FAULT_FALLBACK;
 	if (unlikely(anon_vma_prepare(vma)))
 		return VM_FAULT_OOM;
 	if (unlikely(khugepaged_enter(vma, vma->vm_flags)))
@@ -1344,7 +1342,20 @@ struct page *follow_trans_huge_pmd(struct vm_area_struct *vma,
 			update_mmu_cache_pmd(vma, addr, pmd);
 	}
 	if ((flags & FOLL_MLOCK) && (vma->vm_flags & VM_LOCKED)) {
-		if (page->mapping && trylock_page(page)) {
+		/*
+		 * We don't mlock() pte-mapped THPs. This way we can avoid
+		 * leaking mlocked pages into non-VM_LOCKED VMAs.
+		 *
+		 * In most cases the pmd is the only mapping of the page as we
+		 * break COW for the mlock() -- see gup_flags |= FOLL_WRITE for
+		 * writable private mappings in populate_vma_page_range().
+		 *
+		 * The only scenario when we have the page shared here is if we
+		 * mlocking read-only mapping shared over fork(). We skip
+		 * mlocking such pages.
+		 */
+		if (compound_mapcount(page) == 1 && !PageDoubleMap(page) &&
+				page->mapping && trylock_page(page)) {
 			lru_add_drain();
 			if (page->mapping)
 				mlock_vma_page(page);
@@ -2209,8 +2220,6 @@ static bool hugepage_vma_check(struct vm_area_struct *vma)
 	if ((!(vma->vm_flags & VM_HUGEPAGE) && !khugepaged_always()) ||
 	    (vma->vm_flags & VM_NOHUGEPAGE))
 		return false;
-	if (vma->vm_flags & VM_LOCKED)
-		return false;
 	if (!vma->anon_vma || vma->vm_ops)
 		return false;
 	if (is_vma_temporary_stack(vma))
@@ -2851,14 +2860,28 @@ void __split_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd,
 {
 	spinlock_t *ptl;
 	struct mm_struct *mm = vma->vm_mm;
+	struct page *page = NULL;
 	unsigned long haddr = address & HPAGE_PMD_MASK;
 
 	mmu_notifier_invalidate_range_start(mm, haddr, haddr + HPAGE_PMD_SIZE);
 	ptl = pmd_lock(mm, pmd);
-	if (likely(pmd_trans_huge(*pmd)))
-		__split_huge_pmd_locked(vma, pmd, haddr, false);
+	if (unlikely(!pmd_trans_huge(*pmd)))
+		goto out;
+	page = pmd_page(*pmd);
+	__split_huge_pmd_locked(vma, pmd, haddr, false);
+	if (PageMlocked(page))
+		get_page(page);
+	else
+		page = NULL;
+out:
 	spin_unlock(ptl);
 	mmu_notifier_invalidate_range_end(mm, haddr, haddr + HPAGE_PMD_SIZE);
+	if (page) {
+		lock_page(page);
+		munlock_vma_page(page);
+		unlock_page(page);
+		put_page(page);
+	}
 }
 
 static void split_huge_pmd_address(struct vm_area_struct *vma,
diff --git a/mm/memory.c b/mm/memory.c
index 9d5b40892d4d..5a73c6ed8e5c 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -2160,15 +2160,15 @@ static int wp_page_copy(struct mm_struct *mm, struct vm_area_struct *vma,
 
 	pte_unmap_unlock(page_table, ptl);
 	mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
-	/* THP pages are never mlocked */
-	if (old_page && !PageTransCompound(old_page)) {
+	if (old_page) {
 		/*
 		 * Don't let another task, with possibly unlocked vma,
 		 * keep the mlocked page.
 		 */
 		if (page_copied && (vma->vm_flags & VM_LOCKED)) {
 			lock_page(old_page);	/* LRU manipulation */
-			munlock_vma_page(old_page);
+			if (PageMlocked(old_page))
+				munlock_vma_page(old_page);
 			unlock_page(old_page);
 		}
 		page_cache_release(old_page);
diff --git a/mm/mlock.c b/mm/mlock.c
index c6b139ad356a..9197b6721a1e 100644
--- a/mm/mlock.c
+++ b/mm/mlock.c
@@ -82,6 +82,9 @@ void mlock_vma_page(struct page *page)
 	/* Serialize with page migration */
 	BUG_ON(!PageLocked(page));
 
+	VM_BUG_ON_PAGE(PageTail(page), page);
+	VM_BUG_ON_PAGE(PageCompound(page) && PageDoubleMap(page), page);
+
 	if (!TestSetPageMlocked(page)) {
 		mod_zone_page_state(page_zone(page), NR_MLOCK,
 				    hpage_nr_pages(page));
@@ -178,6 +181,8 @@ unsigned int munlock_vma_page(struct page *page)
 	/* For try_to_munlock() and to serialize with page migration */
 	BUG_ON(!PageLocked(page));
 
+	VM_BUG_ON_PAGE(PageTail(page), page);
+
 	/*
 	 * Serialize with any parallel __split_huge_page_refcount() which
 	 * might otherwise copy PageMlocked to part of the tail pages before
@@ -388,6 +393,13 @@ static unsigned long __munlock_pagevec_fill(struct pagevec *pvec,
 		if (!page || page_zone_id(page) != zoneid)
 			break;
 
+		/*
+		 * Do not use pagevec for PTE-mapped THP,
+		 * munlock_vma_pages_range() will handle them.
+		 */
+		if (PageTransCompound(page))
+			break;
+
 		get_page(page);
 		/*
 		 * Increase the address that will be returned *before* the
@@ -443,29 +455,43 @@ void munlock_vma_pages_range(struct vm_area_struct *vma,
 		page = follow_page_mask(vma, start, FOLL_GET | FOLL_DUMP,
 				&page_mask);
 
-		if (page && !IS_ERR(page) && !PageTransCompound(page)) {
-			/*
-			 * Non-huge pages are handled in batches via
-			 * pagevec. The pin from follow_page_mask()
-			 * prevents them from collapsing by THP.
-			 */
-			pagevec_add(&pvec, page);
-			zone = page_zone(page);
-			zoneid = page_zone_id(page);
+		if (page && !IS_ERR(page)) {
+			if (PageTransTail(page)) {
+				VM_BUG_ON_PAGE(PageMlocked(page), page);
+				put_page(page); /* follow_page_mask() */
+			} else if (PageTransHuge(page)) {
+				lock_page(page);
+				/*
+				 * Any THP page found by follow_page_mask() may
+				 * have gotten split before reaching
+				 * munlock_vma_page(), so we need to recompute
+				 * the page_mask here.
+				 */
+				page_mask = munlock_vma_page(page);
+				unlock_page(page);
+				put_page(page); /* follow_page_mask() */
+			} else {
+				/*
+				 * Non-huge pages are handled in batches via
+				 * pagevec. The pin from follow_page_mask()
+				 * prevents them from collapsing by THP.
+				 */
+				pagevec_add(&pvec, page);
+				zone = page_zone(page);
+				zoneid = page_zone_id(page);
 
-			/*
-			 * Try to fill the rest of pagevec using fast
-			 * pte walk. This will also update start to
-			 * the next page to process. Then munlock the
-			 * pagevec.
-			 */
-			start = __munlock_pagevec_fill(&pvec, vma,
-					zoneid, start, end);
-			__munlock_pagevec(&pvec, zone);
-			goto next;
+				/*
+				 * Try to fill the rest of pagevec using fast
+				 * pte walk. This will also update start to
+				 * the next page to process. Then munlock the
+				 * pagevec.
+				 */
+				start = __munlock_pagevec_fill(&pvec, vma,
+						zoneid, start, end);
+				__munlock_pagevec(&pvec, zone);
+				goto next;
+			}
 		}
-		/* It's a bug to munlock in the middle of a THP page */
-		VM_BUG_ON((start >> PAGE_SHIFT) & page_mask);
 		page_increm = 1 + page_mask;
 		start += page_increm * PAGE_SIZE;
 next:
diff --git a/mm/rmap.c b/mm/rmap.c
index 84271cc39d1e..31d8866fb562 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -1282,6 +1282,9 @@ static void page_remove_anon_compound_rmap(struct page *page)
 		nr = HPAGE_PMD_NR;
 	}
 
+	if (unlikely(PageMlocked(page)))
+		clear_page_mlock(page);
+
 	if (nr) {
 		__mod_zone_page_state(page_zone(page), NR_ANON_PAGES, -nr);
 		deferred_split_huge_page(page);
diff --git a/mm/swap.c b/mm/swap.c
index 3d65480422e8..abffc33bb975 100644
--- a/mm/swap.c
+++ b/mm/swap.c
@@ -358,6 +358,7 @@ static void __lru_cache_activate_page(struct page *page)
  */
 void mark_page_accessed(struct page *page)
 {
+	page = compound_head(page);
 	if (!PageActive(page) && !PageUnevictable(page) &&
 			PageReferenced(page)) {