Merge branch 'master' into for-4.9

17 files changed, 524 insertions, 114 deletions

diff --git a/mm/Kconfig b/mm/Kconfig
index 78a23c5c302d..be0ee11fa0d9 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -262,7 +262,14 @@ config COMPACTION
 	select MIGRATION
 	depends on MMU
 	help
-	  Allows the compaction of memory for the allocation of huge pages.
+          Compaction is the only memory management component to form
+          high order (larger physically contiguous) memory blocks
+          reliably. The page allocator relies on compaction heavily and
+          the lack of the feature can lead to unexpected OOM killer
+          invocations for high order memory requests. You shouldn't
+          disable this option unless there really is a strong reason for
+          it and then we would be really interested to hear about that at
+          linux-mm@kvack.org.
 
 #
 # support for page migration
diff --git a/mm/Makefile b/mm/Makefile
index fc059666c760..2ca1faf3fa09 100644
--- a/mm/Makefile
+++ b/mm/Makefile
@@ -21,6 +21,9 @@ KCOV_INSTRUMENT_memcontrol.o := n
 KCOV_INSTRUMENT_mmzone.o := n
 KCOV_INSTRUMENT_vmstat.o := n
 
+# Since __builtin_frame_address does work as used, disable the warning.
+CFLAGS_usercopy.o += $(call cc-disable-warning, frame-address)
+
 mmu-y			:= nommu.o
 mmu-$(CONFIG_MMU)	:= gup.o highmem.o memory.o mincore.o \
 			   mlock.o mmap.o mprotect.o mremap.o msync.o rmap.o \
@@ -99,3 +102,4 @@ obj-$(CONFIG_USERFAULTFD) += userfaultfd.o
 obj-$(CONFIG_IDLE_PAGE_TRACKING) += page_idle.o
 obj-$(CONFIG_FRAME_VECTOR) += frame_vector.o
 obj-$(CONFIG_DEBUG_PAGE_REF) += debug_page_ref.o
+obj-$(CONFIG_HARDENED_USERCOPY) += usercopy.o
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 2373f0a7d340..2db2112aa31e 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -1512,7 +1512,7 @@ static void __split_huge_pmd_locked(struct vm_area_struct *vma, pmd_t *pmd,
 	struct page *page;
 	pgtable_t pgtable;
 	pmd_t _pmd;
-	bool young, write, dirty;
+	bool young, write, dirty, soft_dirty;
 	unsigned long addr;
 	int i;
 
@@ -1546,6 +1546,7 @@ static void __split_huge_pmd_locked(struct vm_area_struct *vma, pmd_t *pmd,
 	write = pmd_write(*pmd);
 	young = pmd_young(*pmd);
 	dirty = pmd_dirty(*pmd);
+	soft_dirty = pmd_soft_dirty(*pmd);
 
 	pmdp_huge_split_prepare(vma, haddr, pmd);
 	pgtable = pgtable_trans_huge_withdraw(mm, pmd);
@@ -1562,6 +1563,8 @@ static void __split_huge_pmd_locked(struct vm_area_struct *vma, pmd_t *pmd,
 			swp_entry_t swp_entry;
 			swp_entry = make_migration_entry(page + i, write);
 			entry = swp_entry_to_pte(swp_entry);
+			if (soft_dirty)
+				entry = pte_swp_mksoft_dirty(entry);
 		} else {
 			entry = mk_pte(page + i, vma->vm_page_prot);
 			entry = maybe_mkwrite(entry, vma);
@@ -1569,6 +1572,8 @@ static void __split_huge_pmd_locked(struct vm_area_struct *vma, pmd_t *pmd,
 				entry = pte_wrprotect(entry);
 			if (!young)
 				entry = pte_mkold(entry);
+			if (soft_dirty)
+				entry = pte_mksoft_dirty(entry);
 		}
 		if (dirty)
 			SetPageDirty(page + i);
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index b9aa1b0b38b0..87e11d8ad536 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -1448,6 +1448,7 @@ static void dissolve_free_huge_page(struct page *page)
 		list_del(&page->lru);
 		h->free_huge_pages--;
 		h->free_huge_pages_node[nid]--;
+		h->max_huge_pages--;
 		update_and_free_page(h, page);
 	}
 	spin_unlock(&hugetlb_lock);
diff --git a/mm/kasan/quarantine.c b/mm/kasan/quarantine.c
index b6728a33a4ac..baabaad4a4aa 100644
--- a/mm/kasan/quarantine.c
+++ b/mm/kasan/quarantine.c
@@ -217,11 +217,8 @@ void quarantine_reduce(void)
 	new_quarantine_size = (READ_ONCE(totalram_pages) << PAGE_SHIFT) /
 		QUARANTINE_FRACTION;
 	percpu_quarantines = QUARANTINE_PERCPU_SIZE * num_online_cpus();
-	if (WARN_ONCE(new_quarantine_size < percpu_quarantines,
-		"Too little memory, disabling global KASAN quarantine.\n"))
-		new_quarantine_size = 0;
-	else
-		new_quarantine_size -= percpu_quarantines;
+	new_quarantine_size = (new_quarantine_size < percpu_quarantines) ?
+		0 : new_quarantine_size - percpu_quarantines;
 	WRITE_ONCE(quarantine_size, new_quarantine_size);
 
 	last = global_quarantine.head;
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 66beca1ad92f..9a6a51a7c416 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2337,8 +2337,11 @@ int memcg_kmem_charge(struct page *page, gfp_t gfp, int order)
 		return 0;
 
 	memcg = get_mem_cgroup_from_mm(current->mm);
-	if (!mem_cgroup_is_root(memcg))
+	if (!mem_cgroup_is_root(memcg)) {
 		ret = memcg_kmem_charge_memcg(page, gfp, order, memcg);
+		if (!ret)
+			__SetPageKmemcg(page);
+	}
 	css_put(&memcg->css);
 	return ret;
 }
@@ -2365,6 +2368,11 @@ void memcg_kmem_uncharge(struct page *page, int order)
 		page_counter_uncharge(&memcg->memsw, nr_pages);
 
 	page->mem_cgroup = NULL;
+
+	/* slab pages do not have PageKmemcg flag set */
+	if (PageKmemcg(page))
+		__ClearPageKmemcg(page);
+
 	css_put_many(&memcg->css, nr_pages);
 }
 #endif /* !CONFIG_SLOB */
@@ -4069,14 +4077,14 @@ static struct cftype mem_cgroup_legacy_files[] = {
 
 static DEFINE_IDR(mem_cgroup_idr);
 
-static void mem_cgroup_id_get(struct mem_cgroup *memcg)
+static void mem_cgroup_id_get_many(struct mem_cgroup *memcg, unsigned int n)
 {
-	atomic_inc(&memcg->id.ref);
+	atomic_add(n, &memcg->id.ref);
 }
 
-static void mem_cgroup_id_put(struct mem_cgroup *memcg)
+static void mem_cgroup_id_put_many(struct mem_cgroup *memcg, unsigned int n)
 {
-	if (atomic_dec_and_test(&memcg->id.ref)) {
+	if (atomic_sub_and_test(n, &memcg->id.ref)) {
 		idr_remove(&mem_cgroup_idr, memcg->id.id);
 		memcg->id.id = 0;
 
@@ -4085,6 +4093,16 @@ static void mem_cgroup_id_put(struct mem_cgroup *memcg)
 	}
 }
 
+static inline void mem_cgroup_id_get(struct mem_cgroup *memcg)
+{
+	mem_cgroup_id_get_many(memcg, 1);
+}
+
+static inline void mem_cgroup_id_put(struct mem_cgroup *memcg)
+{
+	mem_cgroup_id_put_many(memcg, 1);
+}
+
 /**
  * mem_cgroup_from_id - look up a memcg from a memcg id
  * @id: the memcg id to look up
@@ -4719,6 +4737,8 @@ static void __mem_cgroup_clear_mc(void)
 		if (!mem_cgroup_is_root(mc.from))
 			page_counter_uncharge(&mc.from->memsw, mc.moved_swap);
 
+		mem_cgroup_id_put_many(mc.from, mc.moved_swap);
+
 		/*
 		 * we charged both to->memory and to->memsw, so we
 		 * should uncharge to->memory.
@@ -4726,9 +4746,9 @@ static void __mem_cgroup_clear_mc(void)
 		if (!mem_cgroup_is_root(mc.to))
 			page_counter_uncharge(&mc.to->memory, mc.moved_swap);
 
-		css_put_many(&mc.from->css, mc.moved_swap);
+		mem_cgroup_id_get_many(mc.to, mc.moved_swap);
+		css_put_many(&mc.to->css, mc.moved_swap);
 
-		/* we've already done css_get(mc.to) */
 		mc.moved_swap = 0;
 	}
 	memcg_oom_recover(from);
@@ -5537,8 +5557,10 @@ static void uncharge_list(struct list_head *page_list)
 			else
 				nr_file += nr_pages;
 			pgpgout++;
-		} else
+		} else {
 			nr_kmem += 1 << compound_order(page);
+			__ClearPageKmemcg(page);
+		}
 
 		page->mem_cgroup = NULL;
 	} while (next != page_list);
@@ -5781,6 +5803,24 @@ static int __init mem_cgroup_init(void)
 subsys_initcall(mem_cgroup_init);
 
 #ifdef CONFIG_MEMCG_SWAP
+static struct mem_cgroup *mem_cgroup_id_get_online(struct mem_cgroup *memcg)
+{
+	while (!atomic_inc_not_zero(&memcg->id.ref)) {
+		/*
+		 * The root cgroup cannot be destroyed, so it's refcount must
+		 * always be >= 1.
+		 */
+		if (WARN_ON_ONCE(memcg == root_mem_cgroup)) {
+			VM_BUG_ON(1);
+			break;
+		}
+		memcg = parent_mem_cgroup(memcg);
+		if (!memcg)
+			memcg = root_mem_cgroup;
+	}
+	return memcg;
+}
+
 /**
  * mem_cgroup_swapout - transfer a memsw charge to swap
  * @page: page whose memsw charge to transfer
@@ -5790,7 +5830,7 @@ subsys_initcall(mem_cgroup_init);
  */
 void mem_cgroup_swapout(struct page *page, swp_entry_t entry)
 {
-	struct mem_cgroup *memcg;
+	struct mem_cgroup *memcg, *swap_memcg;
 	unsigned short oldid;
 
 	VM_BUG_ON_PAGE(PageLRU(page), page);
@@ -5805,16 +5845,27 @@ void mem_cgroup_swapout(struct page *page, swp_entry_t entry)
 	if (!memcg)
 		return;
 
-	mem_cgroup_id_get(memcg);
-	oldid = swap_cgroup_record(entry, mem_cgroup_id(memcg));
+	/*
+	 * In case the memcg owning these pages has been offlined and doesn't
+	 * have an ID allocated to it anymore, charge the closest online
+	 * ancestor for the swap instead and transfer the memory+swap charge.
+	 */
+	swap_memcg = mem_cgroup_id_get_online(memcg);
+	oldid = swap_cgroup_record(entry, mem_cgroup_id(swap_memcg));
 	VM_BUG_ON_PAGE(oldid, page);
-	mem_cgroup_swap_statistics(memcg, true);
+	mem_cgroup_swap_statistics(swap_memcg, true);
 
 	page->mem_cgroup = NULL;
 
 	if (!mem_cgroup_is_root(memcg))
 		page_counter_uncharge(&memcg->memory, 1);
 
+	if (memcg != swap_memcg) {
+		if (!mem_cgroup_is_root(swap_memcg))
+			page_counter_charge(&swap_memcg->memsw, 1);
+		page_counter_uncharge(&memcg->memsw, 1);
+	}
+
 	/*
 	 * Interrupts should be disabled here because the caller holds the
 	 * mapping->tree_lock lock which is taken with interrupts-off. It is
@@ -5853,11 +5904,14 @@ int mem_cgroup_try_charge_swap(struct page *page, swp_entry_t entry)
 	if (!memcg)
 		return 0;
 
+	memcg = mem_cgroup_id_get_online(memcg);
+
 	if (!mem_cgroup_is_root(memcg) &&
-	    !page_counter_try_charge(&memcg->swap, 1, &counter))
+	    !page_counter_try_charge(&memcg->swap, 1, &counter)) {
+		mem_cgroup_id_put(memcg);
 		return -ENOMEM;
+	}
 
-	mem_cgroup_id_get(memcg);
 	oldid = swap_cgroup_record(entry, mem_cgroup_id(memcg));
 	VM_BUG_ON_PAGE(oldid, page);
 	mem_cgroup_swap_statistics(memcg, true);
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 3894b65b1555..41266dc29f33 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -1219,6 +1219,7 @@ static pg_data_t __ref *hotadd_new_pgdat(int nid, u64 start)
 
 	/* init node's zones as empty zones, we don't have any present pages.*/
 	free_area_init_node(nid, zones_size, start_pfn, zholes_size);
+	pgdat->per_cpu_nodestats = alloc_percpu(struct per_cpu_nodestat);
 
 	/*
 	 * The node we allocated has no zone fallback lists. For avoiding
@@ -1249,6 +1250,7 @@ static pg_data_t __ref *hotadd_new_pgdat(int nid, u64 start)
 static void rollback_node_hotadd(int nid, pg_data_t *pgdat)
 {
 	arch_refresh_nodedata(nid, NULL);
+	free_percpu(pgdat->per_cpu_nodestats);
 	arch_free_nodedata(pgdat);
 	return;
 }
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index d8c4e38fb5f4..2da72a5b6ecc 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -2336,6 +2336,23 @@ out:
 	return ret;
 }
 
+/*
+ * Drop the (possibly final) reference to task->mempolicy.  It needs to be
+ * dropped after task->mempolicy is set to NULL so that any allocation done as
+ * part of its kmem_cache_free(), such as by KASAN, doesn't reference a freed
+ * policy.
+ */
+void mpol_put_task_policy(struct task_struct *task)
+{
+	struct mempolicy *pol;
+
+	task_lock(task);
+	pol = task->mempolicy;
+	task->mempolicy = NULL;
+	task_unlock(task);
+	mpol_put(pol);
+}
+
 static void sp_delete(struct shared_policy *sp, struct sp_node *n)
 {
 	pr_debug("deleting %lx-l%lx\n", n->start, n->end);
diff --git a/mm/oom_kill.c b/mm/oom_kill.c
index 7d0a275df822..d53a9aa00977 100644
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -764,7 +764,7 @@ bool task_will_free_mem(struct task_struct *task)
 {
 	struct mm_struct *mm = task->mm;
 	struct task_struct *p;
-	bool ret;
+	bool ret = true;
 
 	/*
 	 * Skip tasks without mm because it might have passed its exit_mm and
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index fb975cec3518..a2214c64ed3c 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1008,10 +1008,8 @@ static __always_inline bool free_pages_prepare(struct page *page,
 	}
 	if (PageMappingFlags(page))
 		page->mapping = NULL;
-	if (memcg_kmem_enabled() && PageKmemcg(page)) {
+	if (memcg_kmem_enabled() && PageKmemcg(page))
 		memcg_kmem_uncharge(page, order);
-		__ClearPageKmemcg(page);
-	}
 	if (check_free)
 		bad += free_pages_check(page);
 	if (bad)
@@ -3139,54 +3137,6 @@ __alloc_pages_direct_compact(gfp_t gfp_mask, unsigned int order,
 	return NULL;
 }
 
-static inline bool
-should_compact_retry(struct alloc_context *ac, int order, int alloc_flags,
-		     enum compact_result compact_result,
-		     enum compact_priority *compact_priority,
-		     int compaction_retries)
-{
-	int max_retries = MAX_COMPACT_RETRIES;
-
-	if (!order)
-		return false;
-
-	/*
-	 * compaction considers all the zone as desperately out of memory
-	 * so it doesn't really make much sense to retry except when the
-	 * failure could be caused by insufficient priority
-	 */
-	if (compaction_failed(compact_result)) {
-		if (*compact_priority > MIN_COMPACT_PRIORITY) {
-			(*compact_priority)--;
-			return true;
-		}
-		return false;
-	}
-
-	/*
-	 * make sure the compaction wasn't deferred or didn't bail out early
-	 * due to locks contention before we declare that we should give up.
-	 * But do not retry if the given zonelist is not suitable for
-	 * compaction.
-	 */
-	if (compaction_withdrawn(compact_result))
-		return compaction_zonelist_suitable(ac, order, alloc_flags);
-
-	/*
-	 * !costly requests are much more important than __GFP_REPEAT
-	 * costly ones because they are de facto nofail and invoke OOM
-	 * killer to move on while costly can fail and users are ready
-	 * to cope with that. 1/4 retries is rather arbitrary but we
-	 * would need much more detailed feedback from compaction to
-	 * make a better decision.
-	 */
-	if (order > PAGE_ALLOC_COSTLY_ORDER)
-		max_retries /= 4;
-	if (compaction_retries <= max_retries)
-		return true;
-
-	return false;
-}
 #else
 static inline struct page *
 __alloc_pages_direct_compact(gfp_t gfp_mask, unsigned int order,
@@ -3197,6 +3147,8 @@ __alloc_pages_direct_compact(gfp_t gfp_mask, unsigned int order,
 	return NULL;
 }
 
+#endif /* CONFIG_COMPACTION */
+
 static inline bool
 should_compact_retry(struct alloc_context *ac, unsigned int order, int alloc_flags,
 		     enum compact_result compact_result,
@@ -3223,7 +3175,6 @@ should_compact_retry(struct alloc_context *ac, unsigned int order, int alloc_fla
 	}
 	return false;
 }
-#endif /* CONFIG_COMPACTION */
 
 /* Perform direct synchronous page reclaim */
 static int
@@ -3756,12 +3707,10 @@ no_zone:
 	}
 
 out:
-	if (memcg_kmem_enabled() && (gfp_mask & __GFP_ACCOUNT) && page) {
-		if (unlikely(memcg_kmem_charge(page, gfp_mask, order))) {
-			__free_pages(page, order);
-			page = NULL;
-		} else
-			__SetPageKmemcg(page);
+	if (memcg_kmem_enabled() && (gfp_mask & __GFP_ACCOUNT) && page &&
+	    unlikely(memcg_kmem_charge(page, gfp_mask, order) != 0)) {
+		__free_pages(page, order);
+		page = NULL;
 	}
 
 	if (kmemcheck_enabled && page)
@@ -4064,7 +4013,7 @@ long si_mem_available(void)
 	int lru;
 
 	for (lru = LRU_BASE; lru < NR_LRU_LISTS; lru++)
-		pages[lru] = global_page_state(NR_LRU_BASE + lru);
+		pages[lru] = global_node_page_state(NR_LRU_BASE + lru);
 
 	for_each_zone(zone)
 		wmark_low += zone->watermark[WMARK_LOW];
@@ -4411,7 +4360,7 @@ static int build_zonelists_node(pg_data_t *pgdat, struct zonelist *zonelist,
 	do {
 		zone_type--;
 		zone = pgdat->node_zones + zone_type;
-		if (populated_zone(zone)) {
+		if (managed_zone(zone)) {
 			zoneref_set_zone(zone,
 				&zonelist->_zonerefs[nr_zones++]);
 			check_highest_zone(zone_type);
@@ -4649,7 +4598,7 @@ static void build_zonelists_in_zone_order(pg_data_t *pgdat, int nr_nodes)
 		for (j = 0; j < nr_nodes; j++) {
 			node = node_order[j];
 			z = &NODE_DATA(node)->node_zones[zone_type];
-			if (populated_zone(z)) {
+			if (managed_zone(z)) {
 				zoneref_set_zone(z,
 					&zonelist->_zonerefs[pos++]);
 				check_highest_zone(zone_type);
@@ -4761,6 +4710,8 @@ int local_memory_node(int node)
 }
 #endif
 
+static void setup_min_unmapped_ratio(void);
+static void setup_min_slab_ratio(void);
 #else	/* CONFIG_NUMA */
 
 static void set_zonelist_order(void)
@@ -5882,9 +5833,6 @@ static void __paginginit free_area_init_core(struct pglist_data *pgdat)
 		zone->managed_pages = is_highmem_idx(j) ? realsize : freesize;
 #ifdef CONFIG_NUMA
 		zone->node = nid;
-		pgdat->min_unmapped_pages += (freesize*sysctl_min_unmapped_ratio)
-						/ 100;
-		pgdat->min_slab_pages += (freesize * sysctl_min_slab_ratio) / 100;
 #endif
 		zone->name = zone_names[j];
 		zone->zone_pgdat = pgdat;
@@ -6805,6 +6753,12 @@ int __meminit init_per_zone_wmark_min(void)
 	setup_per_zone_wmarks();
 	refresh_zone_stat_thresholds();
 	setup_per_zone_lowmem_reserve();
+
+#ifdef CONFIG_NUMA
+	setup_min_unmapped_ratio();
+	setup_min_slab_ratio();
+#endif
+
 	return 0;
 }
 core_initcall(init_per_zone_wmark_min)
@@ -6846,43 +6800,58 @@ int watermark_scale_factor_sysctl_handler(struct ctl_table *table, int write,
 }
 
 #ifdef CONFIG_NUMA
+static void setup_min_unmapped_ratio(void)
+{
+	pg_data_t *pgdat;
+	struct zone *zone;
+
+	for_each_online_pgdat(pgdat)
+		pgdat->min_unmapped_pages = 0;
+
+	for_each_zone(zone)
+		zone->zone_pgdat->min_unmapped_pages += (zone->managed_pages *
+				sysctl_min_unmapped_ratio) / 100;
+}
+
+
 int sysctl_min_unmapped_ratio_sysctl_handler(struct ctl_table *table, int write,
 	void __user *buffer, size_t *length, loff_t *ppos)
 {
-	struct pglist_data *pgdat;
-	struct zone *zone;
 	int rc;
 
 	rc = proc_dointvec_minmax(table, write, buffer, length, ppos);
 	if (rc)
 		return rc;
 
+	setup_min_unmapped_ratio();
+
+	return 0;
+}
+
+static void setup_min_slab_ratio(void)
+{
+	pg_data_t *pgdat;
+	struct zone *zone;
+
 	for_each_online_pgdat(pgdat)
 		pgdat->min_slab_pages = 0;
 
 	for_each_zone(zone)
-		zone->zone_pgdat->min_unmapped_pages += (zone->managed_pages *
-				sysctl_min_unmapped_ratio) / 100;
-	return 0;
+		zone->zone_pgdat->min_slab_pages += (zone->managed_pages *
+				sysctl_min_slab_ratio) / 100;
 }
 
 int sysctl_min_slab_ratio_sysctl_handler(struct ctl_table *table, int write,
 	void __user *buffer, size_t *length, loff_t *ppos)
 {
-	struct pglist_data *pgdat;
-	struct zone *zone;
 	int rc;
 
 	rc = proc_dointvec_minmax(table, write, buffer, length, ppos);
 	if (rc)
 		return rc;
 
-	for_each_online_pgdat(pgdat)
-		pgdat->min_slab_pages = 0;
+	setup_min_slab_ratio();
 
-	for_each_zone(zone)
-		zone->zone_pgdat->min_slab_pages += (zone->managed_pages *
-				sysctl_min_slab_ratio) / 100;
 	return 0;
 }
 #endif
diff --git a/mm/readahead.c b/mm/readahead.c
index 65ec288dc057..c8a955b1297e 100644
--- a/mm/readahead.c
+++ b/mm/readahead.c
@@ -8,6 +8,7 @@
  */
 
 #include <linux/kernel.h>
+#include <linux/dax.h>
 #include <linux/gfp.h>
 #include <linux/export.h>
 #include <linux/blkdev.h>
@@ -544,6 +545,14 @@ do_readahead(struct address_space *mapping, struct file *filp,
 	if (!mapping || !mapping->a_ops)
 		return -EINVAL;
 
+	/*
+	 * Readahead doesn't make sense for DAX inodes, but we don't want it
+	 * to report a failure either.  Instead, we just return success and
+	 * don't do any work.
+	 */
+	if (dax_mapping(mapping))
+		return 0;
+
 	return force_page_cache_readahead(mapping, filp, index, nr);
 }
 
diff --git a/mm/rmap.c b/mm/rmap.c
index 709bc83703b1..1ef36404e7b2 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -1284,8 +1284,9 @@ void page_add_file_rmap(struct page *page, bool compound)
 		VM_BUG_ON_PAGE(!PageSwapBacked(page), page);
 		__inc_node_page_state(page, NR_SHMEM_PMDMAPPED);
 	} else {
-		if (PageTransCompound(page)) {
-			VM_BUG_ON_PAGE(!PageLocked(page), page);
+		if (PageTransCompound(page) && page_mapping(page)) {
+			VM_WARN_ON_ONCE(!PageLocked(page));
+
 			SetPageDoubleMap(compound_head(page));
 			if (PageMlocked(page))
 				clear_page_mlock(compound_head(page));
@@ -1303,7 +1304,7 @@ static void page_remove_file_rmap(struct page *page, bool compound)
 {
 	int i, nr = 1;
 
-	VM_BUG_ON_PAGE(compound && !PageTransHuge(page), page);
+	VM_BUG_ON_PAGE(compound && !PageHead(page), page);
 	lock_page_memcg(page);
 
 	/* Hugepages are not counted in NR_FILE_MAPPED for now. */
diff --git a/mm/shmem.c b/mm/shmem.c
index 7f7748a0f9e1..fd8b2b5741b1 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -3975,7 +3975,9 @@ static ssize_t shmem_enabled_store(struct kobject *kobj,
 
 struct kobj_attribute shmem_enabled_attr =
 	__ATTR(shmem_enabled, 0644, shmem_enabled_show, shmem_enabled_store);
+#endif /* CONFIG_TRANSPARENT_HUGE_PAGECACHE && CONFIG_SYSFS */
 
+#ifdef CONFIG_TRANSPARENT_HUGE_PAGECACHE
 bool shmem_huge_enabled(struct vm_area_struct *vma)
 {
 	struct inode *inode = file_inode(vma->vm_file);
@@ -4006,7 +4008,7 @@ bool shmem_huge_enabled(struct vm_area_struct *vma)
 			return false;
 	}
 }
-#endif /* CONFIG_TRANSPARENT_HUGE_PAGECACHE && CONFIG_SYSFS */
+#endif /* CONFIG_TRANSPARENT_HUGE_PAGECACHE */
 
 #else /* !CONFIG_SHMEM */
 
diff --git a/mm/slab.c b/mm/slab.c
index 261147ba156f..b67271024135 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -4441,6 +4441,36 @@ static int __init slab_proc_init(void)
 module_init(slab_proc_init);
 #endif
 
+#ifdef CONFIG_HARDENED_USERCOPY
+/*
+ * Rejects objects that are incorrectly sized.
+ *
+ * Returns NULL if check passes, otherwise const char * to name of cache
+ * to indicate an error.
+ */
+const char *__check_heap_object(const void *ptr, unsigned long n,
+				struct page *page)
+{
+	struct kmem_cache *cachep;
+	unsigned int objnr;
+	unsigned long offset;
+
+	/* Find and validate object. */
+	cachep = page->slab_cache;
+	objnr = obj_to_index(cachep, page, (void *)ptr);
+	BUG_ON(objnr >= cachep->num);
+
+	/* Find offset within object. */
+	offset = ptr - index_to_obj(cachep, page, objnr) - obj_offset(cachep);
+
+	/* Allow address range falling entirely within object size. */
+	if (offset <= cachep->object_size && n <= cachep->object_size - offset)
+		return NULL;
+
+	return cachep->name;
+}
+#endif /* CONFIG_HARDENED_USERCOPY */
+
 /**
  * ksize - get the actual amount of memory allocated for a given object
  * @objp: Pointer to the object
diff --git a/mm/slub.c b/mm/slub.c
index 850737bdfbd8..9adae58462f8 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -3629,6 +3629,7 @@ static void list_slab_objects(struct kmem_cache *s, struct page *page,
  */
 static void free_partial(struct kmem_cache *s, struct kmem_cache_node *n)
 {
+	LIST_HEAD(discard);
 	struct page *page, *h;
 
 	BUG_ON(irqs_disabled());
@@ -3636,13 +3637,16 @@ static void free_partial(struct kmem_cache *s, struct kmem_cache_node *n)
 	list_for_each_entry_safe(page, h, &n->partial, lru) {
 		if (!page->inuse) {
 			remove_partial(n, page);
-			discard_slab(s, page);
+			list_add(&page->lru, &discard);
 		} else {
 			list_slab_objects(s, page,
 			"Objects remaining in %s on __kmem_cache_shutdown()");
 		}
 	}
 	spin_unlock_irq(&n->list_lock);
+
+	list_for_each_entry_safe(page, h, &discard, lru)
+		discard_slab(s, page);
 }
 
 /*
@@ -3764,6 +3768,46 @@ void *__kmalloc_node(size_t size, gfp_t flags, int node)
 EXPORT_SYMBOL(__kmalloc_node);
 #endif
 
+#ifdef CONFIG_HARDENED_USERCOPY
+/*
+ * Rejects objects that are incorrectly sized.
+ *
+ * Returns NULL if check passes, otherwise const char * to name of cache
+ * to indicate an error.
+ */
+const char *__check_heap_object(const void *ptr, unsigned long n,
+				struct page *page)
+{
+	struct kmem_cache *s;
+	unsigned long offset;
+	size_t object_size;
+
+	/* Find object and usable object size. */
+	s = page->slab_cache;
+	object_size = slab_ksize(s);
+
+	/* Reject impossible pointers. */
+	if (ptr < page_address(page))
+		return s->name;
+
+	/* Find offset within object. */
+	offset = (ptr - page_address(page)) % s->size;
+
+	/* Adjust for redzone and reject if within the redzone. */
+	if (kmem_cache_debug(s) && s->flags & SLAB_RED_ZONE) {
+		if (offset < s->red_left_pad)
+			return s->name;
+		offset -= s->red_left_pad;
+	}
+
+	/* Allow address range falling entirely within object size. */
+	if (offset <= object_size && n <= object_size - offset)
+		return NULL;
+
+	return s->name;
+}
+#endif /* CONFIG_HARDENED_USERCOPY */
+
 static size_t __ksize(const void *object)
 {
 	struct page *page;
diff --git a/mm/usercopy.c b/mm/usercopy.c
new file mode 100644
index 000000000000..a3cc3052f830
--- /dev/null
+++ b/mm/usercopy.c
@@ -0,0 +1,268 @@
+/*
+ * This implements the various checks for CONFIG_HARDENED_USERCOPY*,
+ * which are designed to protect kernel memory from needless exposure
+ * and overwrite under many unintended conditions. This code is based
+ * on PAX_USERCOPY, which is:
+ *
+ * Copyright (C) 2001-2016 PaX Team, Bradley Spengler, Open Source
+ * Security Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ */
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/mm.h>
+#include <linux/slab.h>
+#include <asm/sections.h>
+
+enum {
+	BAD_STACK = -1,
+	NOT_STACK = 0,
+	GOOD_FRAME,
+	GOOD_STACK,
+};
+
+/*
+ * Checks if a given pointer and length is contained by the current
+ * stack frame (if possible).
+ *
+ * Returns:
+ *	NOT_STACK: not at all on the stack
+ *	GOOD_FRAME: fully within a valid stack frame
+ *	GOOD_STACK: fully on the stack (when can't do frame-checking)
+ *	BAD_STACK: error condition (invalid stack position or bad stack frame)
+ */
+static noinline int check_stack_object(const void *obj, unsigned long len)
+{
+	const void * const stack = task_stack_page(current);
+	const void * const stackend = stack + THREAD_SIZE;
+	int ret;
+
+	/* Object is not on the stack at all. */
+	if (obj + len <= stack || stackend <= obj)
+		return NOT_STACK;
+
+	/*
+	 * Reject: object partially overlaps the stack (passing the
+	 * the check above means at least one end is within the stack,
+	 * so if this check fails, the other end is outside the stack).
+	 */
+	if (obj < stack || stackend < obj + len)
+		return BAD_STACK;
+
+	/* Check if object is safely within a valid frame. */
+	ret = arch_within_stack_frames(stack, stackend, obj, len);
+	if (ret)
+		return ret;
+
+	return GOOD_STACK;
+}
+
+static void report_usercopy(const void *ptr, unsigned long len,
+			    bool to_user, const char *type)
+{
+	pr_emerg("kernel memory %s attempt detected %s %p (%s) (%lu bytes)\n",
+		to_user ? "exposure" : "overwrite",
+		to_user ? "from" : "to", ptr, type ? : "unknown", len);
+	/*
+	 * For greater effect, it would be nice to do do_group_exit(),
+	 * but BUG() actually hooks all the lock-breaking and per-arch
+	 * Oops code, so that is used here instead.
+	 */
+	BUG();
+}
+
+/* Returns true if any portion of [ptr,ptr+n) over laps with [low,high). */
+static bool overlaps(const void *ptr, unsigned long n, unsigned long low,
+		     unsigned long high)
+{
+	unsigned long check_low = (uintptr_t)ptr;
+	unsigned long check_high = check_low + n;
+
+	/* Does not overlap if entirely above or entirely below. */
+	if (check_low >= high || check_high <= low)
+		return false;
+
+	return true;
+}
+
+/* Is this address range in the kernel text area? */
+static inline const char *check_kernel_text_object(const void *ptr,
+						   unsigned long n)
+{
+	unsigned long textlow = (unsigned long)_stext;
+	unsigned long texthigh = (unsigned long)_etext;
+	unsigned long textlow_linear, texthigh_linear;
+
+	if (overlaps(ptr, n, textlow, texthigh))
+		return "<kernel text>";
+
+	/*
+	 * Some architectures have virtual memory mappings with a secondary
+	 * mapping of the kernel text, i.e. there is more than one virtual
+	 * kernel address that points to the kernel image. It is usually
+	 * when there is a separate linear physical memory mapping, in that
+	 * __pa() is not just the reverse of __va(). This can be detected
+	 * and checked:
+	 */
+	textlow_linear = (unsigned long)__va(__pa(textlow));
+	/* No different mapping: we're done. */
+	if (textlow_linear == textlow)
+		return NULL;
+
+	/* Check the secondary mapping... */
+	texthigh_linear = (unsigned long)__va(__pa(texthigh));
+	if (overlaps(ptr, n, textlow_linear, texthigh_linear))
+		return "<linear kernel text>";
+
+	return NULL;
+}
+
+static inline const char *check_bogus_address(const void *ptr, unsigned long n)
+{
+	/* Reject if object wraps past end of memory. */
+	if ((unsigned long)ptr + n < (unsigned long)ptr)
+		return "<wrapped address>";
+
+	/* Reject if NULL or ZERO-allocation. */
+	if (ZERO_OR_NULL_PTR(ptr))
+		return "<null>";
+
+	return NULL;
+}
+
+static inline const char *check_heap_object(const void *ptr, unsigned long n,
+					    bool to_user)
+{
+	struct page *page, *endpage;
+	const void *end = ptr + n - 1;
+	bool is_reserved, is_cma;
+
+	/*
+	 * Some architectures (arm64) return true for virt_addr_valid() on
+	 * vmalloced addresses. Work around this by checking for vmalloc
+	 * first.
+	 */
+	if (is_vmalloc_addr(ptr))
+		return NULL;
+
+	if (!virt_addr_valid(ptr))
+		return NULL;
+
+	page = virt_to_head_page(ptr);
+
+	/* Check slab allocator for flags and size. */
+	if (PageSlab(page))
+		return __check_heap_object(ptr, n, page);
+
+	/*
+	 * Sometimes the kernel data regions are not marked Reserved (see
+	 * check below). And sometimes [_sdata,_edata) does not cover
+	 * rodata and/or bss, so check each range explicitly.
+	 */
+
+	/* Allow reads of kernel rodata region (if not marked as Reserved). */
+	if (ptr >= (const void *)__start_rodata &&
+	    end <= (const void *)__end_rodata) {
+		if (!to_user)
+			return "<rodata>";
+		return NULL;
+	}
+
+	/* Allow kernel data region (if not marked as Reserved). */
+	if (ptr >= (const void *)_sdata && end <= (const void *)_edata)
+		return NULL;
+
+	/* Allow kernel bss region (if not marked as Reserved). */
+	if (ptr >= (const void *)__bss_start &&
+	    end <= (const void *)__bss_stop)
+		return NULL;
+
+	/* Is the object wholly within one base page? */
+	if (likely(((unsigned long)ptr & (unsigned long)PAGE_MASK) ==
+		   ((unsigned long)end & (unsigned long)PAGE_MASK)))
+		return NULL;
+
+	/* Allow if start and end are inside the same compound page. */
+	endpage = virt_to_head_page(end);
+	if (likely(endpage == page))
+		return NULL;
+
+	/*
+	 * Reject if range is entirely either Reserved (i.e. special or
+	 * device memory), or CMA. Otherwise, reject since the object spans
+	 * several independently allocated pages.
+	 */
+	is_reserved = PageReserved(page);
+	is_cma = is_migrate_cma_page(page);
+	if (!is_reserved && !is_cma)
+		goto reject;
+
+	for (ptr += PAGE_SIZE; ptr <= end; ptr += PAGE_SIZE) {
+		page = virt_to_head_page(ptr);
+		if (is_reserved && !PageReserved(page))
+			goto reject;
+		if (is_cma && !is_migrate_cma_page(page))
+			goto reject;
+	}
+
+	return NULL;
+
+reject:
+	return "<spans multiple pages>";
+}
+
+/*
+ * Validates that the given object is:
+ * - not bogus address
+ * - known-safe heap or stack object
+ * - not in kernel text
+ */
+void __check_object_size(const void *ptr, unsigned long n, bool to_user)
+{
+	const char *err;
+
+	/* Skip all tests if size is zero. */
+	if (!n)
+		return;
+
+	/* Check for invalid addresses. */
+	err = check_bogus_address(ptr, n);
+	if (err)
+		goto report;
+
+	/* Check for bad heap object. */
+	err = check_heap_object(ptr, n, to_user);
+	if (err)
+		goto report;
+
+	/* Check for bad stack object. */
+	switch (check_stack_object(ptr, n)) {
+	case NOT_STACK:
+		/* Object is not touching the current process stack. */
+		break;
+	case GOOD_FRAME:
+	case GOOD_STACK:
+		/*
+		 * Object is either in the correct frame (when it
+		 * is possible to check) or just generally on the
+		 * process stack (when frame checking not available).
+		 */
+		return;
+	default:
+		err = "<process stack>";
+		goto report;
+	}
+
+	/* Check for object in kernel to avoid text exposure. */
+	err = check_kernel_text_object(ptr, n);
+	if (!err)
+		return;
+
+report:
+	report_usercopy(ptr, n, to_user, err);
+}
+EXPORT_SYMBOL(__check_object_size);
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 374d95d04178..b1e12a1ea9cf 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -1665,7 +1665,7 @@ static bool inactive_reclaimable_pages(struct lruvec *lruvec,
 
 	for (zid = sc->reclaim_idx; zid >= 0; zid--) {
 		zone = &pgdat->node_zones[zid];
-		if (!populated_zone(zone))
+		if (!managed_zone(zone))
 			continue;
 
 		if (zone_page_state_snapshot(zone, NR_ZONE_LRU_BASE +
@@ -2036,7 +2036,7 @@ static bool inactive_list_is_low(struct lruvec *lruvec, bool file,
 		struct zone *zone = &pgdat->node_zones[zid];
 		unsigned long inactive_zone, active_zone;
 
-		if (!populated_zone(zone))
+		if (!managed_zone(zone))
 			continue;
 
 		inactive_zone = zone_page_state(zone,
@@ -2171,7 +2171,7 @@ static void get_scan_count(struct lruvec *lruvec, struct mem_cgroup *memcg,
 
 		for (z = 0; z < MAX_NR_ZONES; z++) {
 			struct zone *zone = &pgdat->node_zones[z];
-			if (!populated_zone(zone))
+			if (!managed_zone(zone))
 				continue;
 
 			total_high_wmark += high_wmark_pages(zone);
@@ -2510,7 +2510,7 @@ static inline bool should_continue_reclaim(struct pglist_data *pgdat,
 	/* If compaction would go ahead or the allocation would succeed, stop */
 	for (z = 0; z <= sc->reclaim_idx; z++) {
 		struct zone *zone = &pgdat->node_zones[z];
-		if (!populated_zone(zone))
+		if (!managed_zone(zone))
 			continue;
 
 		switch (compaction_suitable(zone, sc->order, 0, sc->reclaim_idx)) {
@@ -2840,7 +2840,7 @@ static bool pfmemalloc_watermark_ok(pg_data_t *pgdat)
 
 	for (i = 0; i <= ZONE_NORMAL; i++) {
 		zone = &pgdat->node_zones[i];
-		if (!populated_zone(zone) ||
+		if (!managed_zone(zone) ||
 		    pgdat_reclaimable_pages(pgdat) == 0)
 			continue;
 
@@ -3141,7 +3141,7 @@ static bool prepare_kswapd_sleep(pg_data_t *pgdat, int order, int classzone_idx)
 	for (i = 0; i <= classzone_idx; i++) {
 		struct zone *zone = pgdat->node_zones + i;
 
-		if (!populated_zone(zone))
+		if (!managed_zone(zone))
 			continue;
 
 		if (!zone_balanced(zone, order, classzone_idx))
@@ -3169,7 +3169,7 @@ static bool kswapd_shrink_node(pg_data_t *pgdat,
 	sc->nr_to_reclaim = 0;
 	for (z = 0; z <= sc->reclaim_idx; z++) {
 		zone = pgdat->node_zones + z;
-		if (!populated_zone(zone))
+		if (!managed_zone(zone))
 			continue;
 
 		sc->nr_to_reclaim += max(high_wmark_pages(zone), SWAP_CLUSTER_MAX);
@@ -3242,7 +3242,7 @@ static int balance_pgdat(pg_data_t *pgdat, int order, int classzone_idx)
 		if (buffer_heads_over_limit) {
 			for (i = MAX_NR_ZONES - 1; i >= 0; i--) {
 				zone = pgdat->node_zones + i;
-				if (!populated_zone(zone))
+				if (!managed_zone(zone))
 					continue;
 
 				sc.reclaim_idx = i;
@@ -3262,7 +3262,7 @@ static int balance_pgdat(pg_data_t *pgdat, int order, int classzone_idx)
 		 */
 		for (i = classzone_idx; i >= 0; i--) {
 			zone = pgdat->node_zones + i;
-			if (!populated_zone(zone))
+			if (!managed_zone(zone))
 				continue;
 
 			if (zone_balanced(zone, sc.order, classzone_idx))
@@ -3508,7 +3508,7 @@ void wakeup_kswapd(struct zone *zone, int order, enum zone_type classzone_idx)
 	pg_data_t *pgdat;
 	int z;
 
-	if (!populated_zone(zone))
+	if (!managed_zone(zone))
 		return;
 
 	if (!cpuset_zone_allowed(zone, GFP_KERNEL | __GFP_HARDWALL))
@@ -3522,7 +3522,7 @@ void wakeup_kswapd(struct zone *zone, int order, enum zone_type classzone_idx)
 	/* Only wake kswapd if all zones are unbalanced */
 	for (z = 0; z <= classzone_idx; z++) {
 		zone = pgdat->node_zones + z;
-		if (!populated_zone(zone))
+		if (!managed_zone(zone))
 			continue;
 
 		if (zone_balanced(zone, order, classzone_idx))