Merge 4.18-rc7 into master to pick up the KVM dependcy

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

18 files changed, 98 insertions, 76 deletions

diff --git a/mm/backing-dev.c b/mm/backing-dev.c
index 347cc834c04a..2e5d3df0853d 100644
--- a/mm/backing-dev.c
+++ b/mm/backing-dev.c
@@ -359,15 +359,8 @@ static void wb_shutdown(struct bdi_writeback *wb)
 	spin_lock_bh(&wb->work_lock);
 	if (!test_and_clear_bit(WB_registered, &wb->state)) {
 		spin_unlock_bh(&wb->work_lock);
-		/*
-		 * Wait for wb shutdown to finish if someone else is just
-		 * running wb_shutdown(). Otherwise we could proceed to wb /
-		 * bdi destruction before wb_shutdown() is finished.
-		 */
-		wait_on_bit(&wb->state, WB_shutting_down, TASK_UNINTERRUPTIBLE);
 		return;
 	}
-	set_bit(WB_shutting_down, &wb->state);
 	spin_unlock_bh(&wb->work_lock);
 
 	cgwb_remove_from_bdi_list(wb);
@@ -379,12 +372,6 @@ static void wb_shutdown(struct bdi_writeback *wb)
 	mod_delayed_work(bdi_wq, &wb->dwork, 0);
 	flush_delayed_work(&wb->dwork);
 	WARN_ON(!list_empty(&wb->work_list));
-	/*
-	 * Make sure bit gets cleared after shutdown is finished. Matches with
-	 * the barrier provided by test_and_clear_bit() above.
-	 */
-	smp_wmb();
-	clear_and_wake_up_bit(WB_shutting_down, &wb->state);
 }
 
 static void wb_exit(struct bdi_writeback *wb)
@@ -508,10 +495,12 @@ static void cgwb_release_workfn(struct work_struct *work)
 	struct bdi_writeback *wb = container_of(work, struct bdi_writeback,
 						release_work);
 
+	mutex_lock(&wb->bdi->cgwb_release_mutex);
 	wb_shutdown(wb);
 
 	css_put(wb->memcg_css);
 	css_put(wb->blkcg_css);
+	mutex_unlock(&wb->bdi->cgwb_release_mutex);
 
 	fprop_local_destroy_percpu(&wb->memcg_completions);
 	percpu_ref_exit(&wb->refcnt);
@@ -697,6 +686,7 @@ static int cgwb_bdi_init(struct backing_dev_info *bdi)
 
 	INIT_RADIX_TREE(&bdi->cgwb_tree, GFP_ATOMIC);
 	bdi->cgwb_congested_tree = RB_ROOT;
+	mutex_init(&bdi->cgwb_release_mutex);
 
 	ret = wb_init(&bdi->wb, bdi, 1, GFP_KERNEL);
 	if (!ret) {
@@ -717,7 +707,10 @@ static void cgwb_bdi_unregister(struct backing_dev_info *bdi)
 	spin_lock_irq(&cgwb_lock);
 	radix_tree_for_each_slot(slot, &bdi->cgwb_tree, &iter, 0)
 		cgwb_kill(*slot);
+	spin_unlock_irq(&cgwb_lock);
 
+	mutex_lock(&bdi->cgwb_release_mutex);
+	spin_lock_irq(&cgwb_lock);
 	while (!list_empty(&bdi->wb_list)) {
 		wb = list_first_entry(&bdi->wb_list, struct bdi_writeback,
 				      bdi_node);
@@ -726,6 +719,7 @@ static void cgwb_bdi_unregister(struct backing_dev_info *bdi)
 		spin_lock_irq(&cgwb_lock);
 	}
 	spin_unlock_irq(&cgwb_lock);
+	mutex_unlock(&bdi->cgwb_release_mutex);
 }
 
 /**
diff --git a/mm/debug.c b/mm/debug.c
index 56e2d9125ea5..38c926520c97 100644
--- a/mm/debug.c
+++ b/mm/debug.c
@@ -43,12 +43,25 @@ const struct trace_print_flags vmaflag_names[] = {
 
 void __dump_page(struct page *page, const char *reason)
 {
+	bool page_poisoned = PagePoisoned(page);
+	int mapcount;
+
+	/*
+	 * If struct page is poisoned don't access Page*() functions as that
+	 * leads to recursive loop. Page*() check for poisoned pages, and calls
+	 * dump_page() when detected.
+	 */
+	if (page_poisoned) {
+		pr_emerg("page:%px is uninitialized and poisoned", page);
+		goto hex_only;
+	}
+
 	/*
 	 * Avoid VM_BUG_ON() in page_mapcount().
 	 * page->_mapcount space in struct page is used by sl[aou]b pages to
 	 * encode own info.
 	 */
-	int mapcount = PageSlab(page) ? 0 : page_mapcount(page);
+	mapcount = PageSlab(page) ? 0 : page_mapcount(page);
 
 	pr_emerg("page:%px count:%d mapcount:%d mapping:%px index:%#lx",
 		  page, page_ref_count(page), mapcount,
@@ -60,6 +73,7 @@ void __dump_page(struct page *page, const char *reason)
 
 	pr_emerg("flags: %#lx(%pGp)\n", page->flags, &page->flags);
 
+hex_only:
 	print_hex_dump(KERN_ALERT, "raw: ", DUMP_PREFIX_NONE, 32,
 			sizeof(unsigned long), page,
 			sizeof(struct page), false);
@@ -68,7 +82,7 @@ void __dump_page(struct page *page, const char *reason)
 		pr_alert("page dumped because: %s\n", reason);
 
 #ifdef CONFIG_MEMCG
-	if (page->mem_cgroup)
+	if (!page_poisoned && page->mem_cgroup)
 		pr_alert("page->mem_cgroup:%px\n", page->mem_cgroup);
 #endif
 }
diff --git a/mm/gup.c b/mm/gup.c
index b70d7ba7cc13..fc5f98069f4e 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -1238,8 +1238,6 @@ int __mm_populate(unsigned long start, unsigned long len, int ignore_errors)
 	int locked = 0;
 	long ret = 0;
 
-	VM_BUG_ON(start & ~PAGE_MASK);
-	VM_BUG_ON(len != PAGE_ALIGN(len));
 	end = start + len;
 
 	for (nstart = start; nstart < end; nstart = nend) {
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 1cd7c1a57a14..25346bd99364 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -2084,6 +2084,8 @@ static void __split_huge_pmd_locked(struct vm_area_struct *vma, pmd_t *pmd,
 		if (vma_is_dax(vma))
 			return;
 		page = pmd_page(_pmd);
+		if (!PageDirty(page) && pmd_dirty(_pmd))
+			set_page_dirty(page);
 		if (!PageReferenced(page) && pmd_young(_pmd))
 			SetPageReferenced(page);
 		page_remove_rmap(page, true);
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 3612fbb32e9d..039ddbc574e9 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -2163,6 +2163,7 @@ static void __init gather_bootmem_prealloc(void)
 		 */
 		if (hstate_is_gigantic(h))
 			adjust_managed_page_count(page, 1 << h->order);
+		cond_resched();
 	}
 }
 
diff --git a/mm/kasan/kasan.c b/mm/kasan/kasan.c
index f185455b3406..c3bd5209da38 100644
--- a/mm/kasan/kasan.c
+++ b/mm/kasan/kasan.c
@@ -619,12 +619,13 @@ void kasan_kfree_large(void *ptr, unsigned long ip)
 int kasan_module_alloc(void *addr, size_t size)
 {
 	void *ret;
+	size_t scaled_size;
 	size_t shadow_size;
 	unsigned long shadow_start;
 
 	shadow_start = (unsigned long)kasan_mem_to_shadow(addr);
-	shadow_size = round_up(size >> KASAN_SHADOW_SCALE_SHIFT,
-			PAGE_SIZE);
+	scaled_size = (size + KASAN_SHADOW_MASK) >> KASAN_SHADOW_SCALE_SHIFT;
+	shadow_size = round_up(scaled_size, PAGE_SIZE);
 
 	if (WARN_ON(!PAGE_ALIGNED(shadow_start)))
 		return -EINVAL;
diff --git a/mm/memblock.c b/mm/memblock.c
index cc16d70b8333..4b5d245fafc1 100644
--- a/mm/memblock.c
+++ b/mm/memblock.c
@@ -228,7 +228,8 @@ phys_addr_t __init_memblock memblock_find_in_range_node(phys_addr_t size,
 		 * so we use WARN_ONCE() here to see the stack trace if
 		 * fail happens.
 		 */
-		WARN_ONCE(1, "memblock: bottom-up allocation failed, memory hotunplug may be affected\n");
+		WARN_ONCE(IS_ENABLED(CONFIG_MEMORY_HOTREMOVE),
+			  "memblock: bottom-up allocation failed, memory hotremove may be affected\n");
 	}
 
 	return __memblock_find_range_top_down(start, end, size, align, nid,
@@ -1225,6 +1226,7 @@ phys_addr_t __init memblock_alloc_try_nid(phys_addr_t size, phys_addr_t align, i
 	return memblock_alloc_base(size, align, MEMBLOCK_ALLOC_ACCESSIBLE);
 }
 
+#if defined(CONFIG_NO_BOOTMEM)
 /**
  * memblock_virt_alloc_internal - allocate boot memory block
  * @size: size of memory block to be allocated in bytes
@@ -1432,6 +1434,7 @@ void * __init memblock_virt_alloc_try_nid(
 	      (u64)max_addr);
 	return NULL;
 }
+#endif
 
 /**
  * __memblock_free_early - free boot memory block
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index e6f0d5ef320a..8c0280b3143e 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -850,7 +850,7 @@ static void invalidate_reclaim_iterators(struct mem_cgroup *dead_memcg)
 	int nid;
 	int i;
 
-	while ((memcg = parent_mem_cgroup(memcg))) {
+	for (; memcg; memcg = parent_mem_cgroup(memcg)) {
 		for_each_node(nid) {
 			mz = mem_cgroup_nodeinfo(memcg, nid);
 			for (i = 0; i <= DEF_PRIORITY; i++) {
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 9ac49ef17b4e..01f1a14facc4 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -2505,6 +2505,7 @@ void mpol_shared_policy_init(struct shared_policy *sp, struct mempolicy *mpol)
 
 		/* Create pseudo-vma that contains just the policy */
 		memset(&pvma, 0, sizeof(struct vm_area_struct));
+		vma_init(&pvma, NULL);
 		pvma.vm_end = TASK_SIZE;	/* policy covers entire file */
 		mpol_set_shared_policy(sp, &pvma, new); /* adds ref */
 
diff --git a/mm/mmap.c b/mm/mmap.c
index d1eb87ef4b1a..17bbf4d3e24f 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -182,12 +182,12 @@ static struct vm_area_struct *remove_vma(struct vm_area_struct *vma)
 	if (vma->vm_file)
 		fput(vma->vm_file);
 	mpol_put(vma_policy(vma));
-	kmem_cache_free(vm_area_cachep, vma);
+	vm_area_free(vma);
 	return next;
 }
 
-static int do_brk(unsigned long addr, unsigned long len, struct list_head *uf);
-
+static int do_brk_flags(unsigned long addr, unsigned long request, unsigned long flags,
+		struct list_head *uf);
 SYSCALL_DEFINE1(brk, unsigned long, brk)
 {
 	unsigned long retval;
@@ -245,7 +245,7 @@ SYSCALL_DEFINE1(brk, unsigned long, brk)
 		goto out;
 
 	/* Ok, looks good - let it rip. */
-	if (do_brk(oldbrk, newbrk-oldbrk, &uf) < 0)
+	if (do_brk_flags(oldbrk, newbrk-oldbrk, 0, &uf) < 0)
 		goto out;
 
 set_brk:
@@ -911,7 +911,7 @@ again:
 			anon_vma_merge(vma, next);
 		mm->map_count--;
 		mpol_put(vma_policy(next));
-		kmem_cache_free(vm_area_cachep, next);
+		vm_area_free(next);
 		/*
 		 * In mprotect's case 6 (see comments on vma_merge),
 		 * we must remove another next too. It would clutter
@@ -1729,19 +1729,17 @@ unsigned long mmap_region(struct file *file, unsigned long addr,
 	 * specific mapper. the address has already been validated, but
 	 * not unmapped, but the maps are removed from the list.
 	 */
-	vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
+	vma = vm_area_alloc(mm);
 	if (!vma) {
 		error = -ENOMEM;
 		goto unacct_error;
 	}
 
-	vma->vm_mm = mm;
 	vma->vm_start = addr;
 	vma->vm_end = addr + len;
 	vma->vm_flags = vm_flags;
 	vma->vm_page_prot = vm_get_page_prot(vm_flags);
 	vma->vm_pgoff = pgoff;
-	INIT_LIST_HEAD(&vma->anon_vma_chain);
 
 	if (file) {
 		if (vm_flags & VM_DENYWRITE) {
@@ -1780,6 +1778,8 @@ unsigned long mmap_region(struct file *file, unsigned long addr,
 		error = shmem_zero_setup(vma);
 		if (error)
 			goto free_vma;
+	} else {
+		vma_set_anonymous(vma);
 	}
 
 	vma_link(mm, vma, prev, rb_link, rb_parent);
@@ -1832,7 +1832,7 @@ allow_write_and_free_vma:
 	if (vm_flags & VM_DENYWRITE)
 		allow_write_access(file);
 free_vma:
-	kmem_cache_free(vm_area_cachep, vma);
+	vm_area_free(vma);
 unacct_error:
 	if (charged)
 		vm_unacct_memory(charged);
@@ -2620,15 +2620,10 @@ int __split_vma(struct mm_struct *mm, struct vm_area_struct *vma,
 			return err;
 	}
 
-	new = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL);
+	new = vm_area_dup(vma);
 	if (!new)
 		return -ENOMEM;
 
-	/* most fields are the same, copy all, and then fixup */
-	*new = *vma;
-
-	INIT_LIST_HEAD(&new->anon_vma_chain);
-
 	if (new_below)
 		new->vm_end = addr;
 	else {
@@ -2669,7 +2664,7 @@ int __split_vma(struct mm_struct *mm, struct vm_area_struct *vma,
  out_free_mpol:
 	mpol_put(vma_policy(new));
  out_free_vma:
-	kmem_cache_free(vm_area_cachep, new);
+	vm_area_free(new);
 	return err;
 }
 
@@ -2929,21 +2924,14 @@ static inline void verify_mm_writelocked(struct mm_struct *mm)
  *  anonymous maps.  eventually we may be able to do some
  *  brk-specific accounting here.
  */
-static int do_brk_flags(unsigned long addr, unsigned long request, unsigned long flags, struct list_head *uf)
+static int do_brk_flags(unsigned long addr, unsigned long len, unsigned long flags, struct list_head *uf)
 {
 	struct mm_struct *mm = current->mm;
 	struct vm_area_struct *vma, *prev;
-	unsigned long len;
 	struct rb_node **rb_link, *rb_parent;
 	pgoff_t pgoff = addr >> PAGE_SHIFT;
 	int error;
 
-	len = PAGE_ALIGN(request);
-	if (len < request)
-		return -ENOMEM;
-	if (!len)
-		return 0;
-
 	/* Until we need other flags, refuse anything except VM_EXEC. */
 	if ((flags & (~VM_EXEC)) != 0)
 		return -EINVAL;
@@ -2991,14 +2979,13 @@ static int do_brk_flags(unsigned long addr, unsigned long request, unsigned long
 	/*
 	 * create a vma struct for an anonymous mapping
 	 */
-	vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
+	vma = vm_area_alloc(mm);
 	if (!vma) {
 		vm_unacct_memory(len >> PAGE_SHIFT);
 		return -ENOMEM;
 	}
 
-	INIT_LIST_HEAD(&vma->anon_vma_chain);
-	vma->vm_mm = mm;
+	vma_set_anonymous(vma);
 	vma->vm_start = addr;
 	vma->vm_end = addr + len;
 	vma->vm_pgoff = pgoff;
@@ -3015,18 +3002,20 @@ out:
 	return 0;
 }
 
-static int do_brk(unsigned long addr, unsigned long len, struct list_head *uf)
-{
-	return do_brk_flags(addr, len, 0, uf);
-}
-
-int vm_brk_flags(unsigned long addr, unsigned long len, unsigned long flags)
+int vm_brk_flags(unsigned long addr, unsigned long request, unsigned long flags)
 {
 	struct mm_struct *mm = current->mm;
+	unsigned long len;
 	int ret;
 	bool populate;
 	LIST_HEAD(uf);
 
+	len = PAGE_ALIGN(request);
+	if (len < request)
+		return -ENOMEM;
+	if (!len)
+		return 0;
+
 	if (down_write_killable(&mm->mmap_sem))
 		return -EINTR;
 
@@ -3207,16 +3196,14 @@ struct vm_area_struct *copy_vma(struct vm_area_struct **vmap,
 		}
 		*need_rmap_locks = (new_vma->vm_pgoff <= vma->vm_pgoff);
 	} else {
-		new_vma = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL);
+		new_vma = vm_area_dup(vma);
 		if (!new_vma)
 			goto out;
-		*new_vma = *vma;
 		new_vma->vm_start = addr;
 		new_vma->vm_end = addr + len;
 		new_vma->vm_pgoff = pgoff;
 		if (vma_dup_policy(vma, new_vma))
 			goto out_free_vma;
-		INIT_LIST_HEAD(&new_vma->anon_vma_chain);
 		if (anon_vma_clone(new_vma, vma))
 			goto out_free_mempol;
 		if (new_vma->vm_file)
@@ -3231,7 +3218,7 @@ struct vm_area_struct *copy_vma(struct vm_area_struct **vmap,
 out_free_mempol:
 	mpol_put(vma_policy(new_vma));
 out_free_vma:
-	kmem_cache_free(vm_area_cachep, new_vma);
+	vm_area_free(new_vma);
 out:
 	return NULL;
 }
@@ -3355,12 +3342,10 @@ static struct vm_area_struct *__install_special_mapping(
 	int ret;
 	struct vm_area_struct *vma;
 
-	vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
+	vma = vm_area_alloc(mm);
 	if (unlikely(vma == NULL))
 		return ERR_PTR(-ENOMEM);
 
-	INIT_LIST_HEAD(&vma->anon_vma_chain);
-	vma->vm_mm = mm;
 	vma->vm_start = addr;
 	vma->vm_end = addr + len;
 
@@ -3381,7 +3366,7 @@ static struct vm_area_struct *__install_special_mapping(
 	return vma;
 
 out:
-	kmem_cache_free(vm_area_cachep, vma);
+	vm_area_free(vma);
 	return ERR_PTR(ret);
 }
 
diff --git a/mm/nommu.c b/mm/nommu.c
index 4452d8bd9ae4..9fc9e43335b6 100644
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -769,7 +769,7 @@ static void delete_vma(struct mm_struct *mm, struct vm_area_struct *vma)
 	if (vma->vm_file)
 		fput(vma->vm_file);
 	put_nommu_region(vma->vm_region);
-	kmem_cache_free(vm_area_cachep, vma);
+	vm_area_free(vma);
 }
 
 /*
@@ -1145,6 +1145,8 @@ static int do_mmap_private(struct vm_area_struct *vma,
 		if (ret < len)
 			memset(base + ret, 0, len - ret);
 
+	} else {
+		vma_set_anonymous(vma);
 	}
 
 	return 0;
@@ -1204,7 +1206,7 @@ unsigned long do_mmap(struct file *file,
 	if (!region)
 		goto error_getting_region;
 
-	vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
+	vma = vm_area_alloc(current->mm);
 	if (!vma)
 		goto error_getting_vma;
 
@@ -1212,7 +1214,6 @@ unsigned long do_mmap(struct file *file,
 	region->vm_flags = vm_flags;
 	region->vm_pgoff = pgoff;
 
-	INIT_LIST_HEAD(&vma->anon_vma_chain);
 	vma->vm_flags = vm_flags;
 	vma->vm_pgoff = pgoff;
 
@@ -1368,7 +1369,7 @@ error:
 	kmem_cache_free(vm_region_jar, region);
 	if (vma->vm_file)
 		fput(vma->vm_file);
-	kmem_cache_free(vm_area_cachep, vma);
+	vm_area_free(vma);
 	return ret;
 
 sharing_violation:
@@ -1469,14 +1470,13 @@ int split_vma(struct mm_struct *mm, struct vm_area_struct *vma,
 	if (!region)
 		return -ENOMEM;
 
-	new = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL);
+	new = vm_area_dup(vma);
 	if (!new) {
 		kmem_cache_free(vm_region_jar, region);
 		return -ENOMEM;
 	}
 
 	/* most fields are the same, copy all, and then fixup */
-	*new = *vma;
 	*region = *vma->vm_region;
 	new->vm_region = region;
 
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 1521100f1e63..a790ef4be74e 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -6383,7 +6383,7 @@ void __paginginit free_area_init_node(int nid, unsigned long *zones_size,
 	free_area_init_core(pgdat);
 }
 
-#ifdef CONFIG_HAVE_MEMBLOCK
+#if defined(CONFIG_HAVE_MEMBLOCK) && !defined(CONFIG_FLAT_NODE_MEM_MAP)
 /*
  * Only struct pages that are backed by physical memory are zeroed and
  * initialized by going through __init_single_page(). But, there are some
@@ -6421,7 +6421,7 @@ void __paginginit zero_resv_unavail(void)
 	if (pgcnt)
 		pr_info("Reserved but unavailable: %lld pages", pgcnt);
 }
-#endif /* CONFIG_HAVE_MEMBLOCK */
+#endif /* CONFIG_HAVE_MEMBLOCK && !CONFIG_FLAT_NODE_MEM_MAP */
 
 #ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
 
@@ -6847,6 +6847,7 @@ void __init free_area_init_nodes(unsigned long *max_zone_pfn)
 	/* Initialise every node */
 	mminit_verify_pageflags_layout();
 	setup_nr_node_ids();
+	zero_resv_unavail();
 	for_each_online_node(nid) {
 		pg_data_t *pgdat = NODE_DATA(nid);
 		free_area_init_node(nid, NULL,
@@ -6857,7 +6858,6 @@ void __init free_area_init_nodes(unsigned long *max_zone_pfn)
 			node_set_state(nid, N_MEMORY);
 		check_for_memory(pgdat, nid);
 	}
-	zero_resv_unavail();
 }
 
 static int __init cmdline_parse_core(char *p, unsigned long *core,
@@ -7033,9 +7033,9 @@ void __init set_dma_reserve(unsigned long new_dma_reserve)
 
 void __init free_area_init(unsigned long *zones_size)
 {
+	zero_resv_unavail();
 	free_area_init_node(0, zones_size,
 			__pa(PAGE_OFFSET) >> PAGE_SHIFT, NULL);
-	zero_resv_unavail();
 }
 
 static int page_alloc_cpu_dead(unsigned int cpu)
diff --git a/mm/rmap.c b/mm/rmap.c
index 6db729dc4c50..eb477809a5c0 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -64,6 +64,7 @@
 #include <linux/backing-dev.h>
 #include <linux/page_idle.h>
 #include <linux/memremap.h>
+#include <linux/userfaultfd_k.h>
 
 #include <asm/tlbflush.h>
 
@@ -1481,11 +1482,16 @@ static bool try_to_unmap_one(struct page *page, struct vm_area_struct *vma,
 				set_pte_at(mm, address, pvmw.pte, pteval);
 			}
 
-		} else if (pte_unused(pteval)) {
+		} else if (pte_unused(pteval) && !userfaultfd_armed(vma)) {
 			/*
 			 * The guest indicated that the page content is of no
 			 * interest anymore. Simply discard the pte, vmscan
 			 * will take care of the rest.
+			 * A future reference will then fault in a new zero
+			 * page. When userfaultfd is active, we must not drop
+			 * this page though, as its main user (postcopy
+			 * migration) will not expect userfaults on already
+			 * copied pages.
 			 */
 			dec_mm_counter(mm, mm_counter(page));
 			/* We have to invalidate as we cleared the pte */
diff --git a/mm/shmem.c b/mm/shmem.c
index 2cab84403055..41b9bbf24e16 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -1421,6 +1421,7 @@ static void shmem_pseudo_vma_init(struct vm_area_struct *vma,
 {
 	/* Create a pseudo vma that just contains the policy */
 	memset(vma, 0, sizeof(*vma));
+	vma_init(vma, NULL);
 	/* Bias interleave by inode number to distribute better across nodes */
 	vma->vm_pgoff = index + info->vfs_inode.i_ino;
 	vma->vm_policy = mpol_shared_policy_lookup(&info->policy, index);
diff --git a/mm/slab_common.c b/mm/slab_common.c
index 890b1f04a03a..2296caf87bfb 100644
--- a/mm/slab_common.c
+++ b/mm/slab_common.c
@@ -567,10 +567,14 @@ static int shutdown_cache(struct kmem_cache *s)
 	list_del(&s->list);
 
 	if (s->flags & SLAB_TYPESAFE_BY_RCU) {
+#ifdef SLAB_SUPPORTS_SYSFS
+		sysfs_slab_unlink(s);
+#endif
 		list_add_tail(&s->list, &slab_caches_to_rcu_destroy);
 		schedule_work(&slab_caches_to_rcu_destroy_work);
 	} else {
 #ifdef SLAB_SUPPORTS_SYSFS
+		sysfs_slab_unlink(s);
 		sysfs_slab_release(s);
 #else
 		slab_kmem_cache_release(s);
diff --git a/mm/slub.c b/mm/slub.c
index a3b8467c14af..51258eff4178 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -5667,7 +5667,6 @@ static void sysfs_slab_remove_workfn(struct work_struct *work)
 	kset_unregister(s->memcg_kset);
 #endif
 	kobject_uevent(&s->kobj, KOBJ_REMOVE);
-	kobject_del(&s->kobj);
 out:
 	kobject_put(&s->kobj);
 }
@@ -5752,6 +5751,12 @@ static void sysfs_slab_remove(struct kmem_cache *s)
 	schedule_work(&s->kobj_remove_work);
 }
 
+void sysfs_slab_unlink(struct kmem_cache *s)
+{
+	if (slab_state >= FULL)
+		kobject_del(&s->kobj);
+}
+
 void sysfs_slab_release(struct kmem_cache *s)
 {
 	if (slab_state >= FULL)
diff --git a/mm/vmstat.c b/mm/vmstat.c
index 75eda9c2b260..8ba0870ecddd 100644
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -1796,11 +1796,9 @@ static void vmstat_update(struct work_struct *w)
 		 * to occur in the future. Keep on running the
 		 * update worker thread.
 		 */
-		preempt_disable();
 		queue_delayed_work_on(smp_processor_id(), mm_percpu_wq,
 				this_cpu_ptr(&vmstat_work),
 				round_jiffies_relative(sysctl_stat_interval));
-		preempt_enable();
 	}
 }
 
diff --git a/mm/zswap.c b/mm/zswap.c
index 7d34e69507e3..cd91fd9d96b8 100644
--- a/mm/zswap.c
+++ b/mm/zswap.c
@@ -1026,6 +1026,15 @@ static int zswap_frontswap_store(unsigned type, pgoff_t offset,
 			ret = -ENOMEM;
 			goto reject;
 		}
+
+		/* A second zswap_is_full() check after
+		 * zswap_shrink() to make sure it's now
+		 * under the max_pool_percent
+		 */
+		if (zswap_is_full()) {
+			ret = -ENOMEM;
+			goto reject;
+		}
 	}
 
 	/* allocate entry */