Merge branch 'akpm' (patches from Andrew)

Merge misc VM fixes from Andrew Morton:
 "A bunch of hotfixes, all affecting mm/.

  The two-patch series from Andrea may be controversial. This restores
  patches which were reverted in Dec 2018 due to a regression report [*].

  After extensive discussion it is evident that the problems which these
  patches solved were significantly more serious than the problems they
  introduced. I am told that major distros are already carrying these
  two patches for this reason"

[*] See

      https://lore.kernel.org/lkml/alpine.DEB.2.21.1812061343240.144733@chino.kir.corp.google.com/
      https://lore.kernel.org/lkml/alpine.DEB.2.21.1812031545560.161134@chino.kir.corp.google.com/

  for the google-specific issues brought up by David Rijentes. And as
  Andrew says:

    "I'm unaware of anyone else who will be adversely affected by this,
     and google already carries over a thousand kernel patches - another
     won't kill them.

     There has been sporadic discussion about fixing these things for
     real but it's clear that nobody apart from David is particularly
     motivated"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
  hugetlbfs: fix hugetlb page migration/fault race causing SIGBUS
  mm, vmscan: do not special-case slab reclaim when watermarks are boosted
  Revert "mm, thp: restore node-local hugepage allocations"
  Revert "Revert "mm, thp: consolidate THP gfp handling into alloc_hugepage_direct_gfpmask""
  include/asm-generic/5level-fixup.h: fix variable 'p4d' set but not used
  seq_file: fix problem when seeking mid-record
  mm: workingset: fix vmstat counters for shadow nodes
  mm/usercopy: use memory range to be accessed for wraparound check
  mm: kmemleak: disable early logging in case of error
  mm/vmalloc.c: fix percpu free VM area search criteria
  mm/memcontrol.c: fix use after free in mem_cgroup_iter()
  mm/z3fold.c: fix z3fold_destroy_pool() race condition
  mm/z3fold.c: fix z3fold_destroy_pool() ordering
  mm: mempolicy: handle vma with unmovable pages mapped correctly in mbind
  mm: mempolicy: make the behavior consistent when MPOL_MF_MOVE* and MPOL_MF_STRICT were specified
  mm/hmm: fix bad subpage pointer in try_to_unmap_one
  mm/hmm: fix ZONE_DEVICE anon page mapping reuse
  mm: document zone device struct page field usage

13 files changed, 240 insertions, 110 deletions

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 1334ede667a8..738065f765ab 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -644,30 +644,40 @@ release:
  *	    available
  * never: never stall for any thp allocation
  */
-static inline gfp_t alloc_hugepage_direct_gfpmask(struct vm_area_struct *vma)
+static inline gfp_t alloc_hugepage_direct_gfpmask(struct vm_area_struct *vma, unsigned long addr)
 {
 	const bool vma_madvised = !!(vma->vm_flags & VM_HUGEPAGE);
+	gfp_t this_node = 0;
+
+#ifdef CONFIG_NUMA
+	struct mempolicy *pol;
+	/*
+	 * __GFP_THISNODE is used only when __GFP_DIRECT_RECLAIM is not
+	 * specified, to express a general desire to stay on the current
+	 * node for optimistic allocation attempts. If the defrag mode
+	 * and/or madvise hint requires the direct reclaim then we prefer
+	 * to fallback to other node rather than node reclaim because that
+	 * can lead to excessive reclaim even though there is free memory
+	 * on other nodes. We expect that NUMA preferences are specified
+	 * by memory policies.
+	 */
+	pol = get_vma_policy(vma, addr);
+	if (pol->mode != MPOL_BIND)
+		this_node = __GFP_THISNODE;
+	mpol_cond_put(pol);
+#endif
 
-	/* Always do synchronous compaction */
 	if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags))
 		return GFP_TRANSHUGE | (vma_madvised ? 0 : __GFP_NORETRY);
-
-	/* Kick kcompactd and fail quickly */
 	if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags))
-		return GFP_TRANSHUGE_LIGHT | __GFP_KSWAPD_RECLAIM;
-
-	/* Synchronous compaction if madvised, otherwise kick kcompactd */
+		return GFP_TRANSHUGE_LIGHT | __GFP_KSWAPD_RECLAIM | this_node;
 	if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags))
-		return GFP_TRANSHUGE_LIGHT |
-			(vma_madvised ? __GFP_DIRECT_RECLAIM :
-					__GFP_KSWAPD_RECLAIM);
-
-	/* Only do synchronous compaction if madvised */
+		return GFP_TRANSHUGE_LIGHT | (vma_madvised ? __GFP_DIRECT_RECLAIM :
+							     __GFP_KSWAPD_RECLAIM | this_node);
 	if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags))
-		return GFP_TRANSHUGE_LIGHT |
-		       (vma_madvised ? __GFP_DIRECT_RECLAIM : 0);
-
-	return GFP_TRANSHUGE_LIGHT;
+		return GFP_TRANSHUGE_LIGHT | (vma_madvised ? __GFP_DIRECT_RECLAIM :
+							     this_node);
+	return GFP_TRANSHUGE_LIGHT | this_node;
 }
 
 /* Caller must hold page table lock. */
@@ -739,8 +749,8 @@ vm_fault_t do_huge_pmd_anonymous_page(struct vm_fault *vmf)
 			pte_free(vma->vm_mm, pgtable);
 		return ret;
 	}
-	gfp = alloc_hugepage_direct_gfpmask(vma);
-	page = alloc_hugepage_vma(gfp, vma, haddr, HPAGE_PMD_ORDER);
+	gfp = alloc_hugepage_direct_gfpmask(vma, haddr);
+	page = alloc_pages_vma(gfp, HPAGE_PMD_ORDER, vma, haddr, numa_node_id());
 	if (unlikely(!page)) {
 		count_vm_event(THP_FAULT_FALLBACK);
 		return VM_FAULT_FALLBACK;
@@ -1347,8 +1357,9 @@ vm_fault_t do_huge_pmd_wp_page(struct vm_fault *vmf, pmd_t orig_pmd)
 alloc:
 	if (__transparent_hugepage_enabled(vma) &&
 	    !transparent_hugepage_debug_cow()) {
-		huge_gfp = alloc_hugepage_direct_gfpmask(vma);
-		new_page = alloc_hugepage_vma(huge_gfp, vma, haddr, HPAGE_PMD_ORDER);
+		huge_gfp = alloc_hugepage_direct_gfpmask(vma, haddr);
+		new_page = alloc_pages_vma(huge_gfp, HPAGE_PMD_ORDER, vma,
+				haddr, numa_node_id());
 	} else
 		new_page = NULL;
 
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index ede7e7f5d1ab..6d7296dd11b8 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -3856,6 +3856,25 @@ retry:
 
 		page = alloc_huge_page(vma, haddr, 0);
 		if (IS_ERR(page)) {
+			/*
+			 * Returning error will result in faulting task being
+			 * sent SIGBUS.  The hugetlb fault mutex prevents two
+			 * tasks from racing to fault in the same page which
+			 * could result in false unable to allocate errors.
+			 * Page migration does not take the fault mutex, but
+			 * does a clear then write of pte's under page table
+			 * lock.  Page fault code could race with migration,
+			 * notice the clear pte and try to allocate a page
+			 * here.  Before returning error, get ptl and make
+			 * sure there really is no pte entry.
+			 */
+			ptl = huge_pte_lock(h, mm, ptep);
+			if (!huge_pte_none(huge_ptep_get(ptep))) {
+				ret = 0;
+				spin_unlock(ptl);
+				goto out;
+			}
+			spin_unlock(ptl);
 			ret = vmf_error(PTR_ERR(page));
 			goto out;
 		}
diff --git a/mm/kmemleak.c b/mm/kmemleak.c
index 6e9e8cca663e..f6e602918dac 100644
--- a/mm/kmemleak.c
+++ b/mm/kmemleak.c
@@ -1966,6 +1966,7 @@ static void kmemleak_disable(void)
 
 	/* stop any memory operation tracing */
 	kmemleak_enabled = 0;
+	kmemleak_early_log = 0;
 
 	/* check whether it is too early for a kernel thread */
 	if (kmemleak_initialized)
@@ -2009,7 +2010,6 @@ void __init kmemleak_init(void)
 
 #ifdef CONFIG_DEBUG_KMEMLEAK_DEFAULT_OFF
 	if (!kmemleak_skip_disable) {
-		kmemleak_early_log = 0;
 		kmemleak_disable();
 		return;
 	}
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index cdbb7a84cb6e..6f5c0c517c49 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -768,6 +768,26 @@ void __mod_lruvec_state(struct lruvec *lruvec, enum node_stat_item idx,
 	__this_cpu_write(pn->lruvec_stat_cpu->count[idx], x);
 }
 
+void __mod_lruvec_slab_state(void *p, enum node_stat_item idx, int val)
+{
+	struct page *page = virt_to_head_page(p);
+	pg_data_t *pgdat = page_pgdat(page);
+	struct mem_cgroup *memcg;
+	struct lruvec *lruvec;
+
+	rcu_read_lock();
+	memcg = memcg_from_slab_page(page);
+
+	/* Untracked pages have no memcg, no lruvec. Update only the node */
+	if (!memcg || memcg == root_mem_cgroup) {
+		__mod_node_page_state(pgdat, idx, val);
+	} else {
+		lruvec = mem_cgroup_lruvec(pgdat, memcg);
+		__mod_lruvec_state(lruvec, idx, val);
+	}
+	rcu_read_unlock();
+}
+
 /**
  * __count_memcg_events - account VM events in a cgroup
  * @memcg: the memory cgroup
@@ -1130,26 +1150,45 @@ void mem_cgroup_iter_break(struct mem_cgroup *root,
 		css_put(&prev->css);
 }
 
-static void invalidate_reclaim_iterators(struct mem_cgroup *dead_memcg)
+static void __invalidate_reclaim_iterators(struct mem_cgroup *from,
+					struct mem_cgroup *dead_memcg)
 {
-	struct mem_cgroup *memcg = dead_memcg;
 	struct mem_cgroup_reclaim_iter *iter;
 	struct mem_cgroup_per_node *mz;
 	int nid;
 	int i;
 
-	for (; memcg; memcg = parent_mem_cgroup(memcg)) {
-		for_each_node(nid) {
-			mz = mem_cgroup_nodeinfo(memcg, nid);
-			for (i = 0; i <= DEF_PRIORITY; i++) {
-				iter = &mz->iter[i];
-				cmpxchg(&iter->position,
-					dead_memcg, NULL);
-			}
+	for_each_node(nid) {
+		mz = mem_cgroup_nodeinfo(from, nid);
+		for (i = 0; i <= DEF_PRIORITY; i++) {
+			iter = &mz->iter[i];
+			cmpxchg(&iter->position,
+				dead_memcg, NULL);
 		}
 	}
 }
 
+static void invalidate_reclaim_iterators(struct mem_cgroup *dead_memcg)
+{
+	struct mem_cgroup *memcg = dead_memcg;
+	struct mem_cgroup *last;
+
+	do {
+		__invalidate_reclaim_iterators(memcg, dead_memcg);
+		last = memcg;
+	} while ((memcg = parent_mem_cgroup(memcg)));
+
+	/*
+	 * When cgruop1 non-hierarchy mode is used,
+	 * parent_mem_cgroup() does not walk all the way up to the
+	 * cgroup root (root_mem_cgroup). So we have to handle
+	 * dead_memcg from cgroup root separately.
+	 */
+	if (last != root_mem_cgroup)
+		__invalidate_reclaim_iterators(root_mem_cgroup,
+						dead_memcg);
+}
+
 /**
  * mem_cgroup_scan_tasks - iterate over tasks of a memory cgroup hierarchy
  * @memcg: hierarchy root
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index f48693f75b37..65e0874fce17 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -403,7 +403,7 @@ static const struct mempolicy_operations mpol_ops[MPOL_MAX] = {
 	},
 };
 
-static void migrate_page_add(struct page *page, struct list_head *pagelist,
+static int migrate_page_add(struct page *page, struct list_head *pagelist,
 				unsigned long flags);
 
 struct queue_pages {
@@ -429,11 +429,14 @@ static inline bool queue_pages_required(struct page *page,
 }
 
 /*
- * queue_pages_pmd() has three possible return values:
- * 1 - pages are placed on the right node or queued successfully.
- * 0 - THP was split.
- * -EIO - is migration entry or MPOL_MF_STRICT was specified and an existing
- *        page was already on a node that does not follow the policy.
+ * queue_pages_pmd() has four possible return values:
+ * 0 - pages are placed on the right node or queued successfully.
+ * 1 - there is unmovable page, and MPOL_MF_MOVE* & MPOL_MF_STRICT were
+ *     specified.
+ * 2 - THP was split.
+ * -EIO - is migration entry or only MPOL_MF_STRICT was specified and an
+ *        existing page was already on a node that does not follow the
+ *        policy.
  */
 static int queue_pages_pmd(pmd_t *pmd, spinlock_t *ptl, unsigned long addr,
 				unsigned long end, struct mm_walk *walk)
@@ -451,23 +454,20 @@ static int queue_pages_pmd(pmd_t *pmd, spinlock_t *ptl, unsigned long addr,
 	if (is_huge_zero_page(page)) {
 		spin_unlock(ptl);
 		__split_huge_pmd(walk->vma, pmd, addr, false, NULL);
+		ret = 2;
 		goto out;
 	}
-	if (!queue_pages_required(page, qp)) {
-		ret = 1;
+	if (!queue_pages_required(page, qp))
 		goto unlock;
-	}
 
-	ret = 1;
 	flags = qp->flags;
 	/* go to thp migration */
 	if (flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL)) {
-		if (!vma_migratable(walk->vma)) {
-			ret = -EIO;
+		if (!vma_migratable(walk->vma) ||
+		    migrate_page_add(page, qp->pagelist, flags)) {
+			ret = 1;
 			goto unlock;
 		}
-
-		migrate_page_add(page, qp->pagelist, flags);
 	} else
 		ret = -EIO;
 unlock:
@@ -479,6 +479,13 @@ out:
 /*
  * Scan through pages checking if pages follow certain conditions,
  * and move them to the pagelist if they do.
+ *
+ * queue_pages_pte_range() has three possible return values:
+ * 0 - pages are placed on the right node or queued successfully.
+ * 1 - there is unmovable page, and MPOL_MF_MOVE* & MPOL_MF_STRICT were
+ *     specified.
+ * -EIO - only MPOL_MF_STRICT was specified and an existing page was already
+ *        on a node that does not follow the policy.
  */
 static int queue_pages_pte_range(pmd_t *pmd, unsigned long addr,
 			unsigned long end, struct mm_walk *walk)
@@ -488,17 +495,17 @@ static int queue_pages_pte_range(pmd_t *pmd, unsigned long addr,
 	struct queue_pages *qp = walk->private;
 	unsigned long flags = qp->flags;
 	int ret;
+	bool has_unmovable = false;
 	pte_t *pte;
 	spinlock_t *ptl;
 
 	ptl = pmd_trans_huge_lock(pmd, vma);
 	if (ptl) {
 		ret = queue_pages_pmd(pmd, ptl, addr, end, walk);
-		if (ret > 0)
-			return 0;
-		else if (ret < 0)
+		if (ret != 2)
 			return ret;
 	}
+	/* THP was split, fall through to pte walk */
 
 	if (pmd_trans_unstable(pmd))
 		return 0;
@@ -519,14 +526,28 @@ static int queue_pages_pte_range(pmd_t *pmd, unsigned long addr,
 		if (!queue_pages_required(page, qp))
 			continue;
 		if (flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL)) {
-			if (!vma_migratable(vma))
+			/* MPOL_MF_STRICT must be specified if we get here */
+			if (!vma_migratable(vma)) {
+				has_unmovable = true;
 				break;
-			migrate_page_add(page, qp->pagelist, flags);
+			}
+
+			/*
+			 * Do not abort immediately since there may be
+			 * temporary off LRU pages in the range.  Still
+			 * need migrate other LRU pages.
+			 */
+			if (migrate_page_add(page, qp->pagelist, flags))
+				has_unmovable = true;
 		} else
 			break;
 	}
 	pte_unmap_unlock(pte - 1, ptl);
 	cond_resched();
+
+	if (has_unmovable)
+		return 1;
+
 	return addr != end ? -EIO : 0;
 }
 
@@ -639,7 +660,13 @@ static int queue_pages_test_walk(unsigned long start, unsigned long end,
  *
  * If pages found in a given range are on a set of nodes (determined by
  * @nodes and @flags,) it's isolated and queued to the pagelist which is
- * passed via @private.)
+ * passed via @private.
+ *
+ * queue_pages_range() has three possible return values:
+ * 1 - there is unmovable page, but MPOL_MF_MOVE* & MPOL_MF_STRICT were
+ *     specified.
+ * 0 - queue pages successfully or no misplaced page.
+ * -EIO - there is misplaced page and only MPOL_MF_STRICT was specified.
  */
 static int
 queue_pages_range(struct mm_struct *mm, unsigned long start, unsigned long end,
@@ -940,7 +967,7 @@ static long do_get_mempolicy(int *policy, nodemask_t *nmask,
 /*
  * page migration, thp tail pages can be passed.
  */
-static void migrate_page_add(struct page *page, struct list_head *pagelist,
+static int migrate_page_add(struct page *page, struct list_head *pagelist,
 				unsigned long flags)
 {
 	struct page *head = compound_head(page);
@@ -953,8 +980,19 @@ static void migrate_page_add(struct page *page, struct list_head *pagelist,
 			mod_node_page_state(page_pgdat(head),
 				NR_ISOLATED_ANON + page_is_file_cache(head),
 				hpage_nr_pages(head));
+		} else if (flags & MPOL_MF_STRICT) {
+			/*
+			 * Non-movable page may reach here.  And, there may be
+			 * temporary off LRU pages or non-LRU movable pages.
+			 * Treat them as unmovable pages since they can't be
+			 * isolated, so they can't be moved at the moment.  It
+			 * should return -EIO for this case too.
+			 */
+			return -EIO;
 		}
 	}
+
+	return 0;
 }
 
 /* page allocation callback for NUMA node migration */
@@ -1142,8 +1180,8 @@ static struct page *new_page(struct page *page, unsigned long start)
 	} else if (PageTransHuge(page)) {
 		struct page *thp;
 
-		thp = alloc_hugepage_vma(GFP_TRANSHUGE, vma, address,
-					 HPAGE_PMD_ORDER);
+		thp = alloc_pages_vma(GFP_TRANSHUGE, HPAGE_PMD_ORDER, vma,
+				address, numa_node_id());
 		if (!thp)
 			return NULL;
 		prep_transhuge_page(thp);
@@ -1157,9 +1195,10 @@ static struct page *new_page(struct page *page, unsigned long start)
 }
 #else
 
-static void migrate_page_add(struct page *page, struct list_head *pagelist,
+static int migrate_page_add(struct page *page, struct list_head *pagelist,
 				unsigned long flags)
 {
+	return -EIO;
 }
 
 int do_migrate_pages(struct mm_struct *mm, const nodemask_t *from,
@@ -1182,6 +1221,7 @@ static long do_mbind(unsigned long start, unsigned long len,
 	struct mempolicy *new;
 	unsigned long end;
 	int err;
+	int ret;
 	LIST_HEAD(pagelist);
 
 	if (flags & ~(unsigned long)MPOL_MF_VALID)
@@ -1243,10 +1283,15 @@ static long do_mbind(unsigned long start, unsigned long len,
 	if (err)
 		goto mpol_out;
 
-	err = queue_pages_range(mm, start, end, nmask,
+	ret = queue_pages_range(mm, start, end, nmask,
 			  flags | MPOL_MF_INVERT, &pagelist);
-	if (!err)
-		err = mbind_range(mm, start, end, new);
+
+	if (ret < 0) {
+		err = -EIO;
+		goto up_out;
+	}
+
+	err = mbind_range(mm, start, end, new);
 
 	if (!err) {
 		int nr_failed = 0;
@@ -1259,13 +1304,14 @@ static long do_mbind(unsigned long start, unsigned long len,
 				putback_movable_pages(&pagelist);
 		}
 
-		if (nr_failed && (flags & MPOL_MF_STRICT))
+		if ((ret > 0) || (nr_failed && (flags & MPOL_MF_STRICT)))
 			err = -EIO;
 	} else
 		putback_movable_pages(&pagelist);
 
+up_out:
 	up_write(&mm->mmap_sem);
- mpol_out:
+mpol_out:
 	mpol_put(new);
 	return err;
 }
@@ -1688,7 +1734,7 @@ struct mempolicy *__get_vma_policy(struct vm_area_struct *vma,
  * freeing by another task.  It is the caller's responsibility to free the
  * extra reference for shared policies.
  */
-static struct mempolicy *get_vma_policy(struct vm_area_struct *vma,
+struct mempolicy *get_vma_policy(struct vm_area_struct *vma,
 						unsigned long addr)
 {
 	struct mempolicy *pol = __get_vma_policy(vma, addr);
@@ -2037,7 +2083,6 @@ static struct page *alloc_page_interleave(gfp_t gfp, unsigned order,
  * 	@vma:  Pointer to VMA or NULL if not available.
  *	@addr: Virtual Address of the allocation. Must be inside the VMA.
  *	@node: Which node to prefer for allocation (modulo policy).
- *	@hugepage: for hugepages try only the preferred node if possible
  *
  * 	This function allocates a page from the kernel page pool and applies
  *	a NUMA policy associated with the VMA or the current process.
@@ -2048,7 +2093,7 @@ static struct page *alloc_page_interleave(gfp_t gfp, unsigned order,
  */
 struct page *
 alloc_pages_vma(gfp_t gfp, int order, struct vm_area_struct *vma,
-		unsigned long addr, int node, bool hugepage)
+		unsigned long addr, int node)
 {
 	struct mempolicy *pol;
 	struct page *page;
@@ -2066,31 +2111,6 @@ alloc_pages_vma(gfp_t gfp, int order, struct vm_area_struct *vma,
 		goto out;
 	}
 
-	if (unlikely(IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE) && hugepage)) {
-		int hpage_node = node;
-
-		/*
-		 * For hugepage allocation and non-interleave policy which
-		 * allows the current node (or other explicitly preferred
-		 * node) we only try to allocate from the current/preferred
-		 * node and don't fall back to other nodes, as the cost of
-		 * remote accesses would likely offset THP benefits.
-		 *
-		 * If the policy is interleave, or does not allow the current
-		 * node in its nodemask, we allocate the standard way.
-		 */
-		if (pol->mode == MPOL_PREFERRED && !(pol->flags & MPOL_F_LOCAL))
-			hpage_node = pol->v.preferred_node;
-
-		nmask = policy_nodemask(gfp, pol);
-		if (!nmask || node_isset(hpage_node, *nmask)) {
-			mpol_cond_put(pol);
-			page = __alloc_pages_node(hpage_node,
-						gfp | __GFP_THISNODE, order);
-			goto out;
-		}
-	}
-
 	nmask = policy_nodemask(gfp, pol);
 	preferred_nid = policy_node(gfp, pol, node);
 	page = __alloc_pages_nodemask(gfp, order, preferred_nid, nmask);
diff --git a/mm/memremap.c b/mm/memremap.c
index 86432650f829..ed70c4e8e52a 100644
--- a/mm/memremap.c
+++ b/mm/memremap.c
@@ -403,6 +403,30 @@ void __put_devmap_managed_page(struct page *page)
 
 		mem_cgroup_uncharge(page);
 
+		/*
+		 * When a device_private page is freed, the page->mapping field
+		 * may still contain a (stale) mapping value. For example, the
+		 * lower bits of page->mapping may still identify the page as
+		 * an anonymous page. Ultimately, this entire field is just
+		 * stale and wrong, and it will cause errors if not cleared.
+		 * One example is:
+		 *
+		 *  migrate_vma_pages()
+		 *    migrate_vma_insert_page()
+		 *      page_add_new_anon_rmap()
+		 *        __page_set_anon_rmap()
+		 *          ...checks page->mapping, via PageAnon(page) call,
+		 *            and incorrectly concludes that the page is an
+		 *            anonymous page. Therefore, it incorrectly,
+		 *            silently fails to set up the new anon rmap.
+		 *
+		 * For other types of ZONE_DEVICE pages, migration is either
+		 * handled differently or not done at all, so there is no need
+		 * to clear page->mapping.
+		 */
+		if (is_device_private_page(page))
+			page->mapping = NULL;
+
 		page->pgmap->ops->page_free(page);
 	} else if (!count)
 		__put_page(page);
diff --git a/mm/rmap.c b/mm/rmap.c
index e5dfe2ae6b0d..003377e24232 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -1475,7 +1475,15 @@ static bool try_to_unmap_one(struct page *page, struct vm_area_struct *vma,
 			/*
 			 * No need to invalidate here it will synchronize on
 			 * against the special swap migration pte.
+			 *
+			 * The assignment to subpage above was computed from a
+			 * swap PTE which results in an invalid pointer.
+			 * Since only PAGE_SIZE pages can currently be
+			 * migrated, just set it to page. This will need to be
+			 * changed when hugepage migrations to device private
+			 * memory are supported.
 			 */
+			subpage = page;
 			goto discard;
 		}
 
diff --git a/mm/shmem.c b/mm/shmem.c
index 626d8c74b973..2bed4761f279 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -1466,7 +1466,7 @@ static struct page *shmem_alloc_hugepage(gfp_t gfp,
 
 	shmem_pseudo_vma_init(&pvma, info, hindex);
 	page = alloc_pages_vma(gfp | __GFP_COMP | __GFP_NORETRY | __GFP_NOWARN,
-			HPAGE_PMD_ORDER, &pvma, 0, numa_node_id(), true);
+			HPAGE_PMD_ORDER, &pvma, 0, numa_node_id());
 	shmem_pseudo_vma_destroy(&pvma);
 	if (page)
 		prep_transhuge_page(page);
diff --git a/mm/usercopy.c b/mm/usercopy.c
index 2a09796edef8..98e924864554 100644
--- a/mm/usercopy.c
+++ b/mm/usercopy.c
@@ -147,7 +147,7 @@ static inline void check_bogus_address(const unsigned long ptr, unsigned long n,
 				       bool to_user)
 {
 	/* Reject if object wraps past end of memory. */
-	if (ptr + n < ptr)
+	if (ptr + (n - 1) < ptr)
 		usercopy_abort("wrapped address", NULL, to_user, 0, ptr + n);
 
 	/* Reject if NULL or ZERO-allocation. */
diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index e0fc963acc41..7ba11e12a11f 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -3279,9 +3279,19 @@ retry:
 			goto overflow;
 
 		/*
+		 * If required width exeeds current VA block, move
+		 * base downwards and then recheck.
+		 */
+		if (base + end > va->va_end) {
+			base = pvm_determine_end_from_reverse(&va, align) - end;
+			term_area = area;
+			continue;
+		}
+
+		/*
 		 * If this VA does not fit, move base downwards and recheck.
 		 */
-		if (base + start < va->va_start || base + end > va->va_end) {
+		if (base + start < va->va_start) {
 			va = node_to_va(rb_prev(&va->rb_node));
 			base = pvm_determine_end_from_reverse(&va, align) - end;
 			term_area = area;
diff --git a/mm/vmscan.c b/mm/vmscan.c
index dbdc46a84f63..c77d1e3761a7 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -88,9 +88,6 @@ struct scan_control {
 	/* Can pages be swapped as part of reclaim? */
 	unsigned int may_swap:1;
 
-	/* e.g. boosted watermark reclaim leaves slabs alone */
-	unsigned int may_shrinkslab:1;
-
 	/*
 	 * Cgroups are not reclaimed below their configured memory.low,
 	 * unless we threaten to OOM. If any cgroups are skipped due to
@@ -2714,10 +2711,8 @@ static bool shrink_node(pg_data_t *pgdat, struct scan_control *sc)
 			shrink_node_memcg(pgdat, memcg, sc, &lru_pages);
 			node_lru_pages += lru_pages;
 
-			if (sc->may_shrinkslab) {
-				shrink_slab(sc->gfp_mask, pgdat->node_id,
-				    memcg, sc->priority);
-			}
+			shrink_slab(sc->gfp_mask, pgdat->node_id, memcg,
+					sc->priority);
 
 			/* Record the group's reclaim efficiency */
 			vmpressure(sc->gfp_mask, memcg, false,
@@ -3194,7 +3189,6 @@ unsigned long try_to_free_pages(struct zonelist *zonelist, int order,
 		.may_writepage = !laptop_mode,
 		.may_unmap = 1,
 		.may_swap = 1,
-		.may_shrinkslab = 1,
 	};
 
 	/*
@@ -3238,7 +3232,6 @@ unsigned long mem_cgroup_shrink_node(struct mem_cgroup *memcg,
 		.may_unmap = 1,
 		.reclaim_idx = MAX_NR_ZONES - 1,
 		.may_swap = !noswap,
-		.may_shrinkslab = 1,
 	};
 	unsigned long lru_pages;
 
@@ -3286,7 +3279,6 @@ unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *memcg,
 		.may_writepage = !laptop_mode,
 		.may_unmap = 1,
 		.may_swap = may_swap,
-		.may_shrinkslab = 1,
 	};
 
 	set_task_reclaim_state(current, &sc.reclaim_state);
@@ -3598,7 +3590,6 @@ restart:
 		 */
 		sc.may_writepage = !laptop_mode && !nr_boost_reclaim;
 		sc.may_swap = !nr_boost_reclaim;
-		sc.may_shrinkslab = !nr_boost_reclaim;
 
 		/*
 		 * Do some background aging of the anon list, to give
diff --git a/mm/workingset.c b/mm/workingset.c
index e0b4edcb88c8..c963831d354f 100644
--- a/mm/workingset.c
+++ b/mm/workingset.c
@@ -380,14 +380,12 @@ void workingset_update_node(struct xa_node *node)
 	if (node->count && node->count == node->nr_values) {
 		if (list_empty(&node->private_list)) {
 			list_lru_add(&shadow_nodes, &node->private_list);
-			__inc_lruvec_page_state(virt_to_page(node),
-						WORKINGSET_NODES);
+			__inc_lruvec_slab_state(node, WORKINGSET_NODES);
 		}
 	} else {
 		if (!list_empty(&node->private_list)) {
 			list_lru_del(&shadow_nodes, &node->private_list);
-			__dec_lruvec_page_state(virt_to_page(node),
-						WORKINGSET_NODES);
+			__dec_lruvec_slab_state(node, WORKINGSET_NODES);
 		}
 	}
 }
@@ -480,7 +478,7 @@ static enum lru_status shadow_lru_isolate(struct list_head *item,
 	}
 
 	list_lru_isolate(lru, item);
-	__dec_lruvec_page_state(virt_to_page(node), WORKINGSET_NODES);
+	__dec_lruvec_slab_state(node, WORKINGSET_NODES);
 
 	spin_unlock(lru_lock);
 
@@ -503,7 +501,7 @@ static enum lru_status shadow_lru_isolate(struct list_head *item,
 	 * shadow entries we were tracking ...
 	 */
 	xas_store(&xas, NULL);
-	__inc_lruvec_page_state(virt_to_page(node), WORKINGSET_NODERECLAIM);
+	__inc_lruvec_slab_state(node, WORKINGSET_NODERECLAIM);
 
 out_invalid:
 	xa_unlock_irq(&mapping->i_pages);
diff --git a/mm/z3fold.c b/mm/z3fold.c
index 1a029a7432ee..ed19d98c9dcd 100644
--- a/mm/z3fold.c
+++ b/mm/z3fold.c
@@ -817,9 +817,19 @@ out:
 static void z3fold_destroy_pool(struct z3fold_pool *pool)
 {
 	kmem_cache_destroy(pool->c_handle);
-	z3fold_unregister_migration(pool);
-	destroy_workqueue(pool->release_wq);
+
+	/*
+	 * We need to destroy pool->compact_wq before pool->release_wq,
+	 * as any pending work on pool->compact_wq will call
+	 * queue_work(pool->release_wq, &pool->work).
+	 *
+	 * There are still outstanding pages until both workqueues are drained,
+	 * so we cannot unregister migration until then.
+	 */
+
 	destroy_workqueue(pool->compact_wq);
+	destroy_workqueue(pool->release_wq);
+	z3fold_unregister_migration(pool);
 	kfree(pool);
 }