Merge branch 'akpm' (patches from Andrew)

Merge misc fixes from Andrew Morton:
 "Subsystems affected by this patch series: mm (memremap, memcg,
  slab-generic, kasan, mempolicy, pagecache, oom-kill, pagemap),
  kthread, signals, lib, epoll, and core-kernel"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
  kernel/hung_task.c: make type annotations consistent
  epoll: add a selftest for epoll timeout race
  mm: always have io_remap_pfn_range() set pgprot_decrypted()
  mm, oom: keep oom_adj under or at upper limit when printing
  kthread_worker: prevent queuing delayed work from timer_fn when it is being canceled
  mm/truncate.c: make __invalidate_mapping_pages() static
  lib/crc32test: remove extra local_irq_disable/enable
  ptrace: fix task_join_group_stop() for the case when current is traced
  mm: mempolicy: fix potential pte_unmap_unlock pte error
  kasan: adopt KUNIT tests to SW_TAGS mode
  mm: memcg: link page counters to root if use_hierarchy is false
  mm: memcontrol: correct the NR_ANON_THPS counter of hierarchical memcg
  hugetlb_cgroup: fix reservation accounting
  mm/mremap_pages: fix static key devmap_managed_key updates

fs/proc/base.c

@@ -1049,6 +1049,8 @@ static ssize_t oom_adj_read(struct file *file, char __user *buf, size_t count,
 		oom_adj = (task->signal->oom_score_adj * -OOM_DISABLE) /
 			  OOM_SCORE_ADJ_MAX;
 	put_task_struct(task);
+	if (oom_adj > OOM_ADJUST_MAX)
+		oom_adj = OOM_ADJUST_MAX;
 	len = snprintf(buffer, sizeof(buffer), "%d\n", oom_adj);
 	return simple_read_from_buffer(buf, count, ppos, buffer, len);
 }

include/linux/mm.h

@@ -2759,6 +2759,15 @@ static inline vm_fault_t vmf_insert_page(struct vm_area_struct *vma,
 	return VM_FAULT_NOPAGE;
 }
 
+#ifndef io_remap_pfn_range
+static inline int io_remap_pfn_range(struct vm_area_struct *vma,
+				     unsigned long addr, unsigned long pfn,
+				     unsigned long size, pgprot_t prot)
+{
+	return remap_pfn_range(vma, addr, pfn, size, pgprot_decrypted(prot));
+}
+#endif
+
 static inline vm_fault_t vmf_error(int err)
 {
 	if (err == -ENOMEM)

include/linux/pgtable.h

@@ -1427,10 +1427,6 @@ typedef unsigned int pgtbl_mod_mask;
 
 #endif /* !__ASSEMBLY__ */
 
-#ifndef io_remap_pfn_range
-#define io_remap_pfn_range remap_pfn_range
-#endif
-
 #ifndef has_transparent_hugepage
 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 #define has_transparent_hugepage() 1

kernel/hung_task.c

@@ -225,8 +225,7 @@ static long hung_timeout_jiffies(unsigned long last_checked,
  * Process updating of timeout sysctl
  */
 int proc_dohung_task_timeout_secs(struct ctl_table *table, int write,
-				  void __user *buffer,
-				  size_t *lenp, loff_t *ppos)
+				  void *buffer, size_t *lenp, loff_t *ppos)
 {
 	int ret;
 

kernel/kthread.c

@@ -897,7 +897,8 @@ void kthread_delayed_work_timer_fn(struct timer_list *t)
 	/* Move the work from worker->delayed_work_list. */
 	WARN_ON_ONCE(list_empty(&work->node));
 	list_del_init(&work->node);
-	kthread_insert_work(worker, work, &worker->work_list);
+	if (!work->canceling)
+		kthread_insert_work(worker, work, &worker->work_list);
 
 	raw_spin_unlock_irqrestore(&worker->lock, flags);
 }

kernel/signal.c

@@ -391,16 +391,17 @@ static bool task_participate_group_stop(struct task_struct *task)
 
 void task_join_group_stop(struct task_struct *task)
 {
+	unsigned long mask = current->jobctl & JOBCTL_STOP_SIGMASK;
+	struct signal_struct *sig = current->signal;
+
+	if (sig->group_stop_count) {
+		sig->group_stop_count++;
+		mask |= JOBCTL_STOP_CONSUME;
+	} else if (!(sig->flags & SIGNAL_STOP_STOPPED))
+		return;
+
 	/* Have the new thread join an on-going signal group stop */
-	unsigned long jobctl = current->jobctl;
-	if (jobctl & JOBCTL_STOP_PENDING) {
-		struct signal_struct *sig = current->signal;
-		unsigned long signr = jobctl & JOBCTL_STOP_SIGMASK;
-		unsigned long gstop = JOBCTL_STOP_PENDING | JOBCTL_STOP_CONSUME;
-		if (task_set_jobctl_pending(task, signr | gstop)) {
-			sig->group_stop_count++;
-		}
-	}
+	task_set_jobctl_pending(task, mask | JOBCTL_STOP_PENDING);
 }
 
 /*

lib/crc32test.c

@@ -683,7 +683,6 @@ static int __init crc32c_test(void)
 
 	/* reduce OS noise */
 	local_irq_save(flags);
-	local_irq_disable();
 
 	nsec = ktime_get_ns();
 	for (i = 0; i < 100; i++) {
@@ -694,7 +693,6 @@ static int __init crc32c_test(void)
 	nsec = ktime_get_ns() - nsec;
 
 	local_irq_restore(flags);
-	local_irq_enable();
 
 	pr_info("crc32c: CRC_LE_BITS = %d\n", CRC_LE_BITS);
 
@@ -768,7 +766,6 @@ static int __init crc32_test(void)
 
 	/* reduce OS noise */
 	local_irq_save(flags);
-	local_irq_disable();
 
 	nsec = ktime_get_ns();
 	for (i = 0; i < 100; i++) {
@@ -783,7 +780,6 @@ static int __init crc32_test(void)
 	nsec = ktime_get_ns() - nsec;
 
 	local_irq_restore(flags);
-	local_irq_enable();
 
 	pr_info("crc32: CRC_LE_BITS = %d, CRC_BE BITS = %d\n",
 		 CRC_LE_BITS, CRC_BE_BITS);

lib/test_kasan.c

@@ -216,6 +216,12 @@ static void kmalloc_oob_16(struct kunit *test)
 		u64 words[2];
 	} *ptr1, *ptr2;
 
+	/* This test is specifically crafted for the generic mode. */
+	if (!IS_ENABLED(CONFIG_KASAN_GENERIC)) {
+		kunit_info(test, "CONFIG_KASAN_GENERIC required\n");
+		return;
+	}
+
 	ptr1 = kmalloc(sizeof(*ptr1) - 3, GFP_KERNEL);
 	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr1);
 
@@ -227,6 +233,23 @@ static void kmalloc_oob_16(struct kunit *test)
 	kfree(ptr2);
 }
 
+static void kmalloc_uaf_16(struct kunit *test)
+{
+	struct {
+		u64 words[2];
+	} *ptr1, *ptr2;
+
+	ptr1 = kmalloc(sizeof(*ptr1), GFP_KERNEL);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr1);
+
+	ptr2 = kmalloc(sizeof(*ptr2), GFP_KERNEL);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr2);
+	kfree(ptr2);
+
+	KUNIT_EXPECT_KASAN_FAIL(test, *ptr1 = *ptr2);
+	kfree(ptr1);
+}
+
 static void kmalloc_oob_memset_2(struct kunit *test)
 {
 	char *ptr;
@@ -429,6 +452,12 @@ static void kasan_global_oob(struct kunit *test)
 	volatile int i = 3;
 	char *p = &global_array[ARRAY_SIZE(global_array) + i];
 
+	/* Only generic mode instruments globals. */
+	if (!IS_ENABLED(CONFIG_KASAN_GENERIC)) {
+		kunit_info(test, "CONFIG_KASAN_GENERIC required");
+		return;
+	}
+
 	KUNIT_EXPECT_KASAN_FAIL(test, *(volatile char *)p);
 }
 
@@ -467,6 +496,12 @@ static void kasan_alloca_oob_left(struct kunit *test)
 	char alloca_array[i];
 	char *p = alloca_array - 1;
 
+	/* Only generic mode instruments dynamic allocas. */
+	if (!IS_ENABLED(CONFIG_KASAN_GENERIC)) {
+		kunit_info(test, "CONFIG_KASAN_GENERIC required");
+		return;
+	}
+
 	if (!IS_ENABLED(CONFIG_KASAN_STACK)) {
 		kunit_info(test, "CONFIG_KASAN_STACK is not enabled");
 		return;
@@ -481,6 +516,12 @@ static void kasan_alloca_oob_right(struct kunit *test)
 	char alloca_array[i];
 	char *p = alloca_array + i;
 
+	/* Only generic mode instruments dynamic allocas. */
+	if (!IS_ENABLED(CONFIG_KASAN_GENERIC)) {
+		kunit_info(test, "CONFIG_KASAN_GENERIC required");
+		return;
+	}
+
 	if (!IS_ENABLED(CONFIG_KASAN_STACK)) {
 		kunit_info(test, "CONFIG_KASAN_STACK is not enabled");
 		return;
@@ -551,6 +592,9 @@ static void kasan_memchr(struct kunit *test)
 		return;
 	}
 
+	if (OOB_TAG_OFF)
+		size = round_up(size, OOB_TAG_OFF);
+
 	ptr = kmalloc(size, GFP_KERNEL | __GFP_ZERO);
 	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
 
@@ -573,6 +617,9 @@ static void kasan_memcmp(struct kunit *test)
 		return;
 	}
 
+	if (OOB_TAG_OFF)
+		size = round_up(size, OOB_TAG_OFF);
+
 	ptr = kmalloc(size, GFP_KERNEL | __GFP_ZERO);
 	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
 	memset(arr, 0, sizeof(arr));
@@ -619,13 +666,50 @@ static void kasan_strings(struct kunit *test)
 	KUNIT_EXPECT_KASAN_FAIL(test, kasan_int_result = strnlen(ptr, 1));
 }
 
-static void kasan_bitops(struct kunit *test)
+static void kasan_bitops_modify(struct kunit *test, int nr, void *addr)
+{
+	KUNIT_EXPECT_KASAN_FAIL(test, set_bit(nr, addr));
+	KUNIT_EXPECT_KASAN_FAIL(test, __set_bit(nr, addr));
+	KUNIT_EXPECT_KASAN_FAIL(test, clear_bit(nr, addr));
+	KUNIT_EXPECT_KASAN_FAIL(test, __clear_bit(nr, addr));
+	KUNIT_EXPECT_KASAN_FAIL(test, clear_bit_unlock(nr, addr));
+	KUNIT_EXPECT_KASAN_FAIL(test, __clear_bit_unlock(nr, addr));
+	KUNIT_EXPECT_KASAN_FAIL(test, change_bit(nr, addr));
+	KUNIT_EXPECT_KASAN_FAIL(test, __change_bit(nr, addr));
+}
+
+static void kasan_bitops_test_and_modify(struct kunit *test, int nr, void *addr)
+{
+	KUNIT_EXPECT_KASAN_FAIL(test, test_and_set_bit(nr, addr));
+	KUNIT_EXPECT_KASAN_FAIL(test, __test_and_set_bit(nr, addr));
+	KUNIT_EXPECT_KASAN_FAIL(test, test_and_set_bit_lock(nr, addr));
+	KUNIT_EXPECT_KASAN_FAIL(test, test_and_clear_bit(nr, addr));
+	KUNIT_EXPECT_KASAN_FAIL(test, __test_and_clear_bit(nr, addr));
+	KUNIT_EXPECT_KASAN_FAIL(test, test_and_change_bit(nr, addr));
+	KUNIT_EXPECT_KASAN_FAIL(test, __test_and_change_bit(nr, addr));
+	KUNIT_EXPECT_KASAN_FAIL(test, kasan_int_result = test_bit(nr, addr));
+
+#if defined(clear_bit_unlock_is_negative_byte)
+	KUNIT_EXPECT_KASAN_FAIL(test, kasan_int_result =
+				clear_bit_unlock_is_negative_byte(nr, addr));
+#endif
+}
+
+static void kasan_bitops_generic(struct kunit *test)
 {
+	long *bits;
+
+	/* This test is specifically crafted for the generic mode. */
+	if (!IS_ENABLED(CONFIG_KASAN_GENERIC)) {
+		kunit_info(test, "CONFIG_KASAN_GENERIC required\n");
+		return;
+	}
+
 	/*
 	 * Allocate 1 more byte, which causes kzalloc to round up to 16-bytes;
 	 * this way we do not actually corrupt other memory.
 	 */
-	long *bits = kzalloc(sizeof(*bits) + 1, GFP_KERNEL);
+	bits = kzalloc(sizeof(*bits) + 1, GFP_KERNEL);
 	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, bits);
 
 	/*
@@ -633,55 +717,34 @@ static void kasan_bitops(struct kunit *test)
 	 * below accesses are still out-of-bounds, since bitops are defined to
 	 * operate on the whole long the bit is in.
 	 */
-	KUNIT_EXPECT_KASAN_FAIL(test, set_bit(BITS_PER_LONG, bits));
-
-	KUNIT_EXPECT_KASAN_FAIL(test, __set_bit(BITS_PER_LONG, bits));
-
-	KUNIT_EXPECT_KASAN_FAIL(test, clear_bit(BITS_PER_LONG, bits));
-
-	KUNIT_EXPECT_KASAN_FAIL(test, __clear_bit(BITS_PER_LONG, bits));
-
-	KUNIT_EXPECT_KASAN_FAIL(test, clear_bit_unlock(BITS_PER_LONG, bits));
-
-	KUNIT_EXPECT_KASAN_FAIL(test, __clear_bit_unlock(BITS_PER_LONG, bits));
-
-	KUNIT_EXPECT_KASAN_FAIL(test, change_bit(BITS_PER_LONG, bits));
-
-	KUNIT_EXPECT_KASAN_FAIL(test, __change_bit(BITS_PER_LONG, bits));
+	kasan_bitops_modify(test, BITS_PER_LONG, bits);
 
 	/*
 	 * Below calls try to access bit beyond allocated memory.
 	 */
-	KUNIT_EXPECT_KASAN_FAIL(test,
-		test_and_set_bit(BITS_PER_LONG + BITS_PER_BYTE, bits));
-
-	KUNIT_EXPECT_KASAN_FAIL(test,
-		__test_and_set_bit(BITS_PER_LONG + BITS_PER_BYTE, bits));
-
-	KUNIT_EXPECT_KASAN_FAIL(test,
-		test_and_set_bit_lock(BITS_PER_LONG + BITS_PER_BYTE, bits));
+	kasan_bitops_test_and_modify(test, BITS_PER_LONG + BITS_PER_BYTE, bits);
 
-	KUNIT_EXPECT_KASAN_FAIL(test,
-		test_and_clear_bit(BITS_PER_LONG + BITS_PER_BYTE, bits));
+	kfree(bits);
+}
 
-	KUNIT_EXPECT_KASAN_FAIL(test,
-		__test_and_clear_bit(BITS_PER_LONG + BITS_PER_BYTE, bits));
+static void kasan_bitops_tags(struct kunit *test)
+{
+	long *bits;
 
-	KUNIT_EXPECT_KASAN_FAIL(test,
-		test_and_change_bit(BITS_PER_LONG + BITS_PER_BYTE, bits));
+	/* This test is specifically crafted for the tag-based mode. */
+	if (IS_ENABLED(CONFIG_KASAN_GENERIC)) {
+		kunit_info(test, "CONFIG_KASAN_SW_TAGS required\n");
+		return;
+	}
 
-	KUNIT_EXPECT_KASAN_FAIL(test,
-		__test_and_change_bit(BITS_PER_LONG + BITS_PER_BYTE, bits));
+	/* Allocation size will be rounded to up granule size, which is 16. */
+	bits = kzalloc(sizeof(*bits), GFP_KERNEL);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, bits);
 
-	KUNIT_EXPECT_KASAN_FAIL(test,
-		kasan_int_result =
-			test_bit(BITS_PER_LONG + BITS_PER_BYTE, bits));
+	/* Do the accesses past the 16 allocated bytes. */
+	kasan_bitops_modify(test, BITS_PER_LONG, &bits[1]);
+	kasan_bitops_test_and_modify(test, BITS_PER_LONG + BITS_PER_BYTE, &bits[1]);
 
-#if defined(clear_bit_unlock_is_negative_byte)
-	KUNIT_EXPECT_KASAN_FAIL(test,
-		kasan_int_result = clear_bit_unlock_is_negative_byte(
-			BITS_PER_LONG + BITS_PER_BYTE, bits));
-#endif
 	kfree(bits);
 }
 
@@ -728,6 +791,7 @@ static struct kunit_case kasan_kunit_test_cases[] = {
 	KUNIT_CASE(kmalloc_oob_krealloc_more),
 	KUNIT_CASE(kmalloc_oob_krealloc_less),
 	KUNIT_CASE(kmalloc_oob_16),
+	KUNIT_CASE(kmalloc_uaf_16),
 	KUNIT_CASE(kmalloc_oob_in_memset),
 	KUNIT_CASE(kmalloc_oob_memset_2),
 	KUNIT_CASE(kmalloc_oob_memset_4),
@@ -751,7 +815,8 @@ static struct kunit_case kasan_kunit_test_cases[] = {
 	KUNIT_CASE(kasan_memchr),
 	KUNIT_CASE(kasan_memcmp),
 	KUNIT_CASE(kasan_strings),
-	KUNIT_CASE(kasan_bitops),
+	KUNIT_CASE(kasan_bitops_generic),
+	KUNIT_CASE(kasan_bitops_tags),
 	KUNIT_CASE(kmalloc_double_kzfree),
 	KUNIT_CASE(vmalloc_oob),
 	{}

mm/hugetlb.c

@@ -648,6 +648,8 @@ static long region_del(struct resv_map *resv, long f, long t)
 			}
 
 			del += t - f;
+			hugetlb_cgroup_uncharge_file_region(
+				resv, rg, t - f);
 
 			/* New entry for end of split region */
 			nrg->from = t;
@@ -660,9 +662,6 @@ static long region_del(struct resv_map *resv, long f, long t)
 			/* Original entry is trimmed */
 			rg->to = f;
 
-			hugetlb_cgroup_uncharge_file_region(
-				resv, rg, nrg->to - nrg->from);
-
 			list_add(&nrg->link, &rg->link);
 			nrg = NULL;
 			break;
@@ -678,17 +677,17 @@ static long region_del(struct resv_map *resv, long f, long t)
 		}
 
 		if (f <= rg->from) {	/* Trim beginning of region */
-			del += t - rg->from;
-			rg->from = t;
-
 			hugetlb_cgroup_uncharge_file_region(resv, rg,
 							    t - rg->from);
-		} else {		/* Trim end of region */
-			del += rg->to - f;
-			rg->to = f;
 
+			del += t - rg->from;
+			rg->from = t;
+		} else {		/* Trim end of region */
 			hugetlb_cgroup_uncharge_file_region(resv, rg,
 							    rg->to - f);
+
+			del += rg->to - f;
+			rg->to = f;
 		}
 	}
 
@@ -2443,6 +2442,9 @@ struct page *alloc_huge_page(struct vm_area_struct *vma,
 
 		rsv_adjust = hugepage_subpool_put_pages(spool, 1);
 		hugetlb_acct_memory(h, -rsv_adjust);
+		if (deferred_reserve)
+			hugetlb_cgroup_uncharge_page_rsvd(hstate_index(h),
+					pages_per_huge_page(h), page);
 	}
 	return page;
 

mm/memcontrol.c

@@ -4110,11 +4110,17 @@ static int memcg_stat_show(struct seq_file *m, void *v)
 			   (u64)memsw * PAGE_SIZE);
 
 	for (i = 0; i < ARRAY_SIZE(memcg1_stats); i++) {
+		unsigned long nr;
+
 		if (memcg1_stats[i] == MEMCG_SWAP && !do_memsw_account())
 			continue;
+		nr = memcg_page_state(memcg, memcg1_stats[i]);
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+		if (memcg1_stats[i] == NR_ANON_THPS)
+			nr *= HPAGE_PMD_NR;
+#endif
 		seq_printf(m, "total_%s %llu\n", memcg1_stat_names[i],
-			   (u64)memcg_page_state(memcg, memcg1_stats[i]) *
-			   PAGE_SIZE);
+						(u64)nr * PAGE_SIZE);
 	}
 
 	for (i = 0; i < ARRAY_SIZE(memcg1_events); i++)
@@ -5339,17 +5345,22 @@ mem_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
 		memcg->swappiness = mem_cgroup_swappiness(parent);
 		memcg->oom_kill_disable = parent->oom_kill_disable;
 	}
-	if (parent && parent->use_hierarchy) {
+	if (!parent) {
+		page_counter_init(&memcg->memory, NULL);
+		page_counter_init(&memcg->swap, NULL);
+		page_counter_init(&memcg->kmem, NULL);
+		page_counter_init(&memcg->tcpmem, NULL);
+	} else if (parent->use_hierarchy) {
 		memcg->use_hierarchy = true;
 		page_counter_init(&memcg->memory, &parent->memory);
 		page_counter_init(&memcg->swap, &parent->swap);
 		page_counter_init(&memcg->kmem, &parent->kmem);
 		page_counter_init(&memcg->tcpmem, &parent->tcpmem);
 	} else {
-		page_counter_init(&memcg->memory, NULL);
-		page_counter_init(&memcg->swap, NULL);
-		page_counter_init(&memcg->kmem, NULL);
-		page_counter_init(&memcg->tcpmem, NULL);
+		page_counter_init(&memcg->memory, &root_mem_cgroup->memory);
+		page_counter_init(&memcg->swap, &root_mem_cgroup->swap);
+		page_counter_init(&memcg->kmem, &root_mem_cgroup->kmem);
+		page_counter_init(&memcg->tcpmem, &root_mem_cgroup->tcpmem);
 		/*
 		 * Deeper hierachy with use_hierarchy == false doesn't make
 		 * much sense so let cgroup subsystem know about this

mm/mempolicy.c

@@ -525,7 +525,7 @@ static int queue_pages_pte_range(pmd_t *pmd, unsigned long addr,
 	unsigned long flags = qp->flags;
 	int ret;
 	bool has_unmovable = false;
-	pte_t *pte;
+	pte_t *pte, *mapped_pte;
 	spinlock_t *ptl;
 
 	ptl = pmd_trans_huge_lock(pmd, vma);
@@ -539,7 +539,7 @@ static int queue_pages_pte_range(pmd_t *pmd, unsigned long addr,
 	if (pmd_trans_unstable(pmd))
 		return 0;
 
-	pte = pte_offset_map_lock(walk->mm, pmd, addr, &ptl);
+	mapped_pte = pte = pte_offset_map_lock(walk->mm, pmd, addr, &ptl);
 	for (; addr != end; pte++, addr += PAGE_SIZE) {
 		if (!pte_present(*pte))
 			continue;
@@ -571,7 +571,7 @@ static int queue_pages_pte_range(pmd_t *pmd, unsigned long addr,
 		} else
 			break;
 	}
-	pte_unmap_unlock(pte - 1, ptl);
+	pte_unmap_unlock(mapped_pte, ptl);
 	cond_resched();
 
 	if (has_unmovable)

mm/memremap.c

@@ -41,28 +41,24 @@ EXPORT_SYMBOL_GPL(memremap_compat_align);
 DEFINE_STATIC_KEY_FALSE(devmap_managed_key);
 EXPORT_SYMBOL(devmap_managed_key);
 
-static void devmap_managed_enable_put(void)
+static void devmap_managed_enable_put(struct dev_pagemap *pgmap)
 {
-	static_branch_dec(&devmap_managed_key);
+	if (pgmap->type == MEMORY_DEVICE_PRIVATE ||
+	    pgmap->type == MEMORY_DEVICE_FS_DAX)
+		static_branch_dec(&devmap_managed_key);
 }
 
-static int devmap_managed_enable_get(struct dev_pagemap *pgmap)
+static void devmap_managed_enable_get(struct dev_pagemap *pgmap)
 {
-	if (pgmap->type == MEMORY_DEVICE_PRIVATE &&
-	    (!pgmap->ops || !pgmap->ops->page_free)) {
-		WARN(1, "Missing page_free method\n");
-		return -EINVAL;
-	}
-
-	static_branch_inc(&devmap_managed_key);
-	return 0;
+	if (pgmap->type == MEMORY_DEVICE_PRIVATE ||
+	    pgmap->type == MEMORY_DEVICE_FS_DAX)
+		static_branch_inc(&devmap_managed_key);
 }
 #else
-static int devmap_managed_enable_get(struct dev_pagemap *pgmap)
+static void devmap_managed_enable_get(struct dev_pagemap *pgmap)
 {
-	return -EINVAL;
 }
-static void devmap_managed_enable_put(void)
+static void devmap_managed_enable_put(struct dev_pagemap *pgmap)
 {
 }
 #endif /* CONFIG_DEV_PAGEMAP_OPS */
@@ -169,7 +165,7 @@ void memunmap_pages(struct dev_pagemap *pgmap)
 		pageunmap_range(pgmap, i);
 
 	WARN_ONCE(pgmap->altmap.alloc, "failed to free all reserved pages\n");
-	devmap_managed_enable_put();
+	devmap_managed_enable_put(pgmap);
 }
 EXPORT_SYMBOL_GPL(memunmap_pages);
 
@@ -307,7 +303,6 @@ void *memremap_pages(struct dev_pagemap *pgmap, int nid)
 		.pgprot = PAGE_KERNEL,
 	};
 	const int nr_range = pgmap->nr_range;
-	bool need_devmap_managed = true;
 	int error, i;
 
 	if (WARN_ONCE(!nr_range, "nr_range must be specified\n"))
@@ -323,6 +318,10 @@ void *memremap_pages(struct dev_pagemap *pgmap, int nid)
 			WARN(1, "Missing migrate_to_ram method\n");
 			return ERR_PTR(-EINVAL);
 		}
+		if (!pgmap->ops->page_free) {
+			WARN(1, "Missing page_free method\n");
+			return ERR_PTR(-EINVAL);
+		}
 		if (!pgmap->owner) {
 			WARN(1, "Missing owner\n");
 			return ERR_PTR(-EINVAL);
@@ -336,11 +335,9 @@ void *memremap_pages(struct dev_pagemap *pgmap, int nid)
 		}
 		break;
 	case MEMORY_DEVICE_GENERIC:
-		need_devmap_managed = false;
 		break;
 	case MEMORY_DEVICE_PCI_P2PDMA:
 		params.pgprot = pgprot_noncached(params.pgprot);
-		need_devmap_managed = false;
 		break;
 	default:
 		WARN(1, "Invalid pgmap type %d\n", pgmap->type);
@@ -364,11 +361,7 @@ void *memremap_pages(struct dev_pagemap *pgmap, int nid)
 		}
 	}
 
-	if (need_devmap_managed) {
-		error = devmap_managed_enable_get(pgmap);
-		if (error)
-			return ERR_PTR(error);
-	}
+	devmap_managed_enable_get(pgmap);
 
 	/*
 	 * Clear the pgmap nr_range as it will be incremented for each

mm/truncate.c

@@ -528,7 +528,7 @@ void truncate_inode_pages_final(struct address_space *mapping)
 }
 EXPORT_SYMBOL(truncate_inode_pages_final);
 
-unsigned long __invalidate_mapping_pages(struct address_space *mapping,
+static unsigned long __invalidate_mapping_pages(struct address_space *mapping,
 		pgoff_t start, pgoff_t end, unsigned long *nr_pagevec)
 {
 	pgoff_t indices[PAGEVEC_SIZE];

tools/testing/selftests/filesystems/epoll/epoll_wakeup_test.c

@@ -3282,4 +3282,99 @@ TEST(epoll60)
 	close(ctx.epfd);
 }
 
+struct epoll61_ctx {
+	int epfd;
+	int evfd;
+};
+
+static void *epoll61_write_eventfd(void *ctx_)
+{
+	struct epoll61_ctx *ctx = ctx_;
+	int64_t l = 1;
+
+	usleep(10950);
+	write(ctx->evfd, &l, sizeof(l));
+	return NULL;
+}
+
+static void *epoll61_epoll_with_timeout(void *ctx_)
+{
+	struct epoll61_ctx *ctx = ctx_;
+	struct epoll_event events[1];
+	int n;
+
+	n = epoll_wait(ctx->epfd, events, 1, 11);
+	/*
+	 * If epoll returned the eventfd, write on the eventfd to wake up the
+	 * blocking poller.
+	 */
+	if (n == 1) {
+		int64_t l = 1;
+
+		write(ctx->evfd, &l, sizeof(l));
+	}
+	return NULL;
+}
+
+static void *epoll61_blocking_epoll(void *ctx_)
+{
+	struct epoll61_ctx *ctx = ctx_;
+	struct epoll_event events[1];
+
+	epoll_wait(ctx->epfd, events, 1, -1);
+	return NULL;
+}
+
+TEST(epoll61)
+{
+	struct epoll61_ctx ctx;
+	struct epoll_event ev;
+	int i, r;
+
+	ctx.epfd = epoll_create1(0);
+	ASSERT_GE(ctx.epfd, 0);
+	ctx.evfd = eventfd(0, EFD_NONBLOCK);
+	ASSERT_GE(ctx.evfd, 0);
+
+	ev.events = EPOLLIN | EPOLLET | EPOLLERR | EPOLLHUP;
+	ev.data.ptr = NULL;
+	r = epoll_ctl(ctx.epfd, EPOLL_CTL_ADD, ctx.evfd, &ev);
+	ASSERT_EQ(r, 0);
+
+	/*
+	 * We are testing a race.  Repeat the test case 1000 times to make it
+	 * more likely to fail in case of a bug.
+	 */
+	for (i = 0; i < 1000; i++) {
+		pthread_t threads[3];
+		int n;
+
+		/*
+		 * Start 3 threads:
+		 * Thread 1 sleeps for 10.9ms and writes to the evenfd.
+		 * Thread 2 calls epoll with a timeout of 11ms.
+		 * Thread 3 calls epoll with a timeout of -1.
+		 *
+		 * The eventfd write by Thread 1 should either wakeup Thread 2
+		 * or Thread 3.  If it wakes up Thread 2, Thread 2 writes on the
+		 * eventfd to wake up Thread 3.
+		 *
+		 * If no events are missed, all three threads should eventually
+		 * be joinable.
+		 */
+		ASSERT_EQ(pthread_create(&threads[0], NULL,
+					 epoll61_write_eventfd, &ctx), 0);
+		ASSERT_EQ(pthread_create(&threads[1], NULL,
+					 epoll61_epoll_with_timeout, &ctx), 0);
+		ASSERT_EQ(pthread_create(&threads[2], NULL,
+					 epoll61_blocking_epoll, &ctx), 0);
+
+		for (n = 0; n < ARRAY_SIZE(threads); ++n)
+			ASSERT_EQ(pthread_join(threads[n], NULL), 0);
+	}
+
+	close(ctx.epfd);
+	close(ctx.evfd);
+}
+
 TEST_HARNESS_MAIN