Merge branch 'akpm' (patches from Andrew)

Merge misc fixes from Andrew Morton:
 "7 fixes"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
  mm: fix false-positive WARN_ON() in truncate/invalidate for hugetlb
  kasan: support use-after-scope detection
  kasan: update kasan_global for gcc 7
  lib/debugobjects: export for use in modules
  zram: fix unbalanced idr management at hot removal
  thp: fix corner case of munlock() of PTE-mapped THPs
  mm, thp: propagation of conditional compilation in khugepaged.c

11 files changed, 94 insertions, 14 deletions

diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index 04365b17ee67..5163c8f918cb 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -1403,7 +1403,8 @@ static ssize_t hot_remove_store(struct class *class,
 	zram = idr_find(&zram_index_idr, dev_id);
 	if (zram) {
 		ret = zram_remove(zram);
-		idr_remove(&zram_index_idr, dev_id);
+		if (!ret)
+			idr_remove(&zram_index_idr, dev_id);
 	} else {
 		ret = -ENODEV;
 	}
diff --git a/include/linux/compiler-gcc.h b/include/linux/compiler-gcc.h
index 432f5c97e18f..928e5ca0caee 100644
--- a/include/linux/compiler-gcc.h
+++ b/include/linux/compiler-gcc.h
@@ -263,7 +263,9 @@
 #endif
 #endif /* CONFIG_ARCH_USE_BUILTIN_BSWAP && !__CHECKER__ */
 
-#if GCC_VERSION >= 50000
+#if GCC_VERSION >= 70000
+#define KASAN_ABI_VERSION 5
+#elif GCC_VERSION >= 50000
 #define KASAN_ABI_VERSION 4
 #elif GCC_VERSION >= 40902
 #define KASAN_ABI_VERSION 3
diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index dd15d39e1985..7dbe9148b2f8 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -374,16 +374,13 @@ static inline struct page *read_mapping_page(struct address_space *mapping,
 }
 
 /*
- * Get the offset in PAGE_SIZE.
- * (TODO: hugepage should have ->index in PAGE_SIZE)
+ * Get index of the page with in radix-tree
+ * (TODO: remove once hugetlb pages will have ->index in PAGE_SIZE)
  */
-static inline pgoff_t page_to_pgoff(struct page *page)
+static inline pgoff_t page_to_index(struct page *page)
 {
 	pgoff_t pgoff;
 
-	if (unlikely(PageHeadHuge(page)))
-		return page->index << compound_order(page);
-
 	if (likely(!PageTransTail(page)))
 		return page->index;
 
@@ -397,6 +394,18 @@ static inline pgoff_t page_to_pgoff(struct page *page)
 }
 
 /*
+ * Get the offset in PAGE_SIZE.
+ * (TODO: hugepage should have ->index in PAGE_SIZE)
+ */
+static inline pgoff_t page_to_pgoff(struct page *page)
+{
+	if (unlikely(PageHeadHuge(page)))
+		return page->index << compound_order(page);
+
+	return page_to_index(page);
+}
+
+/*
  * Return byte-offset into filesystem object for page.
  */
 static inline loff_t page_offset(struct page *page)
diff --git a/lib/debugobjects.c b/lib/debugobjects.c
index a8e12601eb37..056052dc8e91 100644
--- a/lib/debugobjects.c
+++ b/lib/debugobjects.c
@@ -362,6 +362,7 @@ void debug_object_init(void *addr, struct debug_obj_descr *descr)
 
 	__debug_object_init(addr, descr, 0);
 }
+EXPORT_SYMBOL_GPL(debug_object_init);
 
 /**
  * debug_object_init_on_stack - debug checks when an object on stack is
@@ -376,6 +377,7 @@ void debug_object_init_on_stack(void *addr, struct debug_obj_descr *descr)
 
 	__debug_object_init(addr, descr, 1);
 }
+EXPORT_SYMBOL_GPL(debug_object_init_on_stack);
 
 /**
  * debug_object_activate - debug checks when an object is activated
@@ -449,6 +451,7 @@ int debug_object_activate(void *addr, struct debug_obj_descr *descr)
 	}
 	return 0;
 }
+EXPORT_SYMBOL_GPL(debug_object_activate);
 
 /**
  * debug_object_deactivate - debug checks when an object is deactivated
@@ -496,6 +499,7 @@ void debug_object_deactivate(void *addr, struct debug_obj_descr *descr)
 
 	raw_spin_unlock_irqrestore(&db->lock, flags);
 }
+EXPORT_SYMBOL_GPL(debug_object_deactivate);
 
 /**
  * debug_object_destroy - debug checks when an object is destroyed
@@ -542,6 +546,7 @@ void debug_object_destroy(void *addr, struct debug_obj_descr *descr)
 out_unlock:
 	raw_spin_unlock_irqrestore(&db->lock, flags);
 }
+EXPORT_SYMBOL_GPL(debug_object_destroy);
 
 /**
  * debug_object_free - debug checks when an object is freed
@@ -582,6 +587,7 @@ void debug_object_free(void *addr, struct debug_obj_descr *descr)
 out_unlock:
 	raw_spin_unlock_irqrestore(&db->lock, flags);
 }
+EXPORT_SYMBOL_GPL(debug_object_free);
 
 /**
  * debug_object_assert_init - debug checks when object should be init-ed
@@ -626,6 +632,7 @@ void debug_object_assert_init(void *addr, struct debug_obj_descr *descr)
 
 	raw_spin_unlock_irqrestore(&db->lock, flags);
 }
+EXPORT_SYMBOL_GPL(debug_object_assert_init);
 
 /**
  * debug_object_active_state - debug checks object usage state machine
@@ -673,6 +680,7 @@ debug_object_active_state(void *addr, struct debug_obj_descr *descr,
 
 	raw_spin_unlock_irqrestore(&db->lock, flags);
 }
+EXPORT_SYMBOL_GPL(debug_object_active_state);
 
 #ifdef CONFIG_DEBUG_OBJECTS_FREE
 static void __debug_check_no_obj_freed(const void *address, unsigned long size)
diff --git a/lib/test_kasan.c b/lib/test_kasan.c
index 5e51872b3fc1..fbdf87920093 100644
--- a/lib/test_kasan.c
+++ b/lib/test_kasan.c
@@ -20,6 +20,11 @@
 #include <linux/uaccess.h>
 #include <linux/module.h>
 
+/*
+ * Note: test functions are marked noinline so that their names appear in
+ * reports.
+ */
+
 static noinline void __init kmalloc_oob_right(void)
 {
 	char *ptr;
@@ -411,6 +416,29 @@ static noinline void __init copy_user_test(void)
 	kfree(kmem);
 }
 
+static noinline void __init use_after_scope_test(void)
+{
+	volatile char *volatile p;
+
+	pr_info("use-after-scope on int\n");
+	{
+		int local = 0;
+
+		p = (char *)&local;
+	}
+	p[0] = 1;
+	p[3] = 1;
+
+	pr_info("use-after-scope on array\n");
+	{
+		char local[1024] = {0};
+
+		p = local;
+	}
+	p[0] = 1;
+	p[1023] = 1;
+}
+
 static int __init kmalloc_tests_init(void)
 {
 	kmalloc_oob_right();
@@ -436,6 +464,7 @@ static int __init kmalloc_tests_init(void)
 	kasan_global_oob();
 	ksize_unpoisons_memory();
 	copy_user_test();
+	use_after_scope_test();
 	return -EAGAIN;
 }
 
diff --git a/mm/kasan/kasan.c b/mm/kasan/kasan.c
index 70c009741aab..0e9505f66ec1 100644
--- a/mm/kasan/kasan.c
+++ b/mm/kasan/kasan.c
@@ -764,6 +764,25 @@ EXPORT_SYMBOL(__asan_storeN_noabort);
 void __asan_handle_no_return(void) {}
 EXPORT_SYMBOL(__asan_handle_no_return);
 
+/* Emitted by compiler to poison large objects when they go out of scope. */
+void __asan_poison_stack_memory(const void *addr, size_t size)
+{
+	/*
+	 * Addr is KASAN_SHADOW_SCALE_SIZE-aligned and the object is surrounded
+	 * by redzones, so we simply round up size to simplify logic.
+	 */
+	kasan_poison_shadow(addr, round_up(size, KASAN_SHADOW_SCALE_SIZE),
+			    KASAN_USE_AFTER_SCOPE);
+}
+EXPORT_SYMBOL(__asan_poison_stack_memory);
+
+/* Emitted by compiler to unpoison large objects when they go into scope. */
+void __asan_unpoison_stack_memory(const void *addr, size_t size)
+{
+	kasan_unpoison_shadow(addr, size);
+}
+EXPORT_SYMBOL(__asan_unpoison_stack_memory);
+
 #ifdef CONFIG_MEMORY_HOTPLUG
 static int kasan_mem_notifier(struct notifier_block *nb,
 			unsigned long action, void *data)
diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h
index e5c2181fee6f..1c260e6b3b3c 100644
--- a/mm/kasan/kasan.h
+++ b/mm/kasan/kasan.h
@@ -21,6 +21,7 @@
 #define KASAN_STACK_MID         0xF2
 #define KASAN_STACK_RIGHT       0xF3
 #define KASAN_STACK_PARTIAL     0xF4
+#define KASAN_USE_AFTER_SCOPE   0xF8
 
 /* Don't break randconfig/all*config builds */
 #ifndef KASAN_ABI_VERSION
@@ -53,6 +54,9 @@ struct kasan_global {
 #if KASAN_ABI_VERSION >= 4
 	struct kasan_source_location *location;
 #endif
+#if KASAN_ABI_VERSION >= 5
+	char *odr_indicator;
+#endif
 };
 
 /**
diff --git a/mm/kasan/report.c b/mm/kasan/report.c
index 24c1211fe9d5..073325aedc68 100644
--- a/mm/kasan/report.c
+++ b/mm/kasan/report.c
@@ -90,6 +90,9 @@ static void print_error_description(struct kasan_access_info *info)
 	case KASAN_KMALLOC_FREE:
 		bug_type = "use-after-free";
 		break;
+	case KASAN_USE_AFTER_SCOPE:
+		bug_type = "use-after-scope";
+		break;
 	}
 
 	pr_err("BUG: KASAN: %s in %pS at addr %p\n",
diff --git a/mm/khugepaged.c b/mm/khugepaged.c
index 728d7790dc2d..87e1a7ca3846 100644
--- a/mm/khugepaged.c
+++ b/mm/khugepaged.c
@@ -103,6 +103,7 @@ static struct khugepaged_scan khugepaged_scan = {
 	.mm_head = LIST_HEAD_INIT(khugepaged_scan.mm_head),
 };
 
+#ifdef CONFIG_SYSFS
 static ssize_t scan_sleep_millisecs_show(struct kobject *kobj,
 					 struct kobj_attribute *attr,
 					 char *buf)
@@ -295,6 +296,7 @@ struct attribute_group khugepaged_attr_group = {
 	.attrs = khugepaged_attr,
 	.name = "khugepaged",
 };
+#endif /* CONFIG_SYSFS */
 
 #define VM_NO_KHUGEPAGED (VM_SPECIAL | VM_HUGETLB)
 
diff --git a/mm/mlock.c b/mm/mlock.c
index 145a4258ddbc..cdbed8aaa426 100644
--- a/mm/mlock.c
+++ b/mm/mlock.c
@@ -190,10 +190,13 @@ unsigned int munlock_vma_page(struct page *page)
 	 */
 	spin_lock_irq(zone_lru_lock(zone));
 
-	nr_pages = hpage_nr_pages(page);
-	if (!TestClearPageMlocked(page))
+	if (!TestClearPageMlocked(page)) {
+		/* Potentially, PTE-mapped THP: do not skip the rest PTEs */
+		nr_pages = 1;
 		goto unlock_out;
+	}
 
+	nr_pages = hpage_nr_pages(page);
 	__mod_zone_page_state(zone, NR_MLOCK, -nr_pages);
 
 	if (__munlock_isolate_lru_page(page, true)) {
diff --git a/mm/truncate.c b/mm/truncate.c
index a01cce450a26..8d8c62d89e6d 100644
--- a/mm/truncate.c
+++ b/mm/truncate.c
@@ -283,7 +283,7 @@ void truncate_inode_pages_range(struct address_space *mapping,
 
 			if (!trylock_page(page))
 				continue;
-			WARN_ON(page_to_pgoff(page) != index);
+			WARN_ON(page_to_index(page) != index);
 			if (PageWriteback(page)) {
 				unlock_page(page);
 				continue;
@@ -371,7 +371,7 @@ void truncate_inode_pages_range(struct address_space *mapping,
 			}
 
 			lock_page(page);
-			WARN_ON(page_to_pgoff(page) != index);
+			WARN_ON(page_to_index(page) != index);
 			wait_on_page_writeback(page);
 			truncate_inode_page(mapping, page);
 			unlock_page(page);
@@ -492,7 +492,7 @@ unsigned long invalidate_mapping_pages(struct address_space *mapping,
 			if (!trylock_page(page))
 				continue;
 
-			WARN_ON(page_to_pgoff(page) != index);
+			WARN_ON(page_to_index(page) != index);
 
 			/* Middle of THP: skip */
 			if (PageTransTail(page)) {
@@ -612,7 +612,7 @@ int invalidate_inode_pages2_range(struct address_space *mapping,
 			}
 
 			lock_page(page);
-			WARN_ON(page_to_pgoff(page) != index);
+			WARN_ON(page_to_index(page) != index);
 			if (page->mapping != mapping) {
 				unlock_page(page);
 				continue;