Merge tag 'mm-stable-2023-02-20-13-37' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull MM updates from Andrew Morton:

 - Daniel Verkamp has contributed a memfd series ("mm/memfd: add
   F_SEAL_EXEC") which permits the setting of the memfd execute bit at
   memfd creation time, with the option of sealing the state of the X
   bit.

 - Peter Xu adds a patch series ("mm/hugetlb: Make huge_pte_offset()
   thread-safe for pmd unshare") which addresses a rare race condition
   related to PMD unsharing.

 - Several folioification patch serieses from Matthew Wilcox, Vishal
   Moola, Sidhartha Kumar and Lorenzo Stoakes

 - Johannes Weiner has a series ("mm: push down lock_page_memcg()")
   which does perform some memcg maintenance and cleanup work.

 - SeongJae Park has added DAMOS filtering to DAMON, with the series
   "mm/damon/core: implement damos filter".

   These filters provide users with finer-grained control over DAMOS's
   actions. SeongJae has also done some DAMON cleanup work.

 - Kairui Song adds a series ("Clean up and fixes for swap").

 - Vernon Yang contributed the series "Clean up and refinement for maple
   tree".

 - Yu Zhao has contributed the "mm: multi-gen LRU: memcg LRU" series. It
   adds to MGLRU an LRU of memcgs, to improve the scalability of global
   reclaim.

 - David Hildenbrand has added some userfaultfd cleanup work in the
   series "mm: uffd-wp + change_protection() cleanups".

 - Christoph Hellwig has removed the generic_writepages() library
   function in the series "remove generic_writepages".

 - Baolin Wang has performed some maintenance on the compaction code in
   his series "Some small improvements for compaction".

 - Sidhartha Kumar is doing some maintenance work on struct page in his
   series "Get rid of tail page fields".

 - David Hildenbrand contributed some cleanup, bugfixing and
   generalization of pte management and of pte debugging in his series
   "mm: support __HAVE_ARCH_PTE_SWP_EXCLUSIVE on all architectures with
   swap PTEs".

 - Mel Gorman and Neil Brown have removed the __GFP_ATOMIC allocation
   flag in the series "Discard __GFP_ATOMIC".

 - Sergey Senozhatsky has improved zsmalloc's memory utilization with
   his series "zsmalloc: make zspage chain size configurable".

 - Joey Gouly has added prctl() support for prohibiting the creation of
   writeable+executable mappings.

   The previous BPF-based approach had shortcomings. See "mm: In-kernel
   support for memory-deny-write-execute (MDWE)".

 - Waiman Long did some kmemleak cleanup and bugfixing in the series
   "mm/kmemleak: Simplify kmemleak_cond_resched() & fix UAF".

 - T.J. Alumbaugh has contributed some MGLRU cleanup work in his series
   "mm: multi-gen LRU: improve".

 - Jiaqi Yan has provided some enhancements to our memory error
   statistics reporting, mainly by presenting the statistics on a
   per-node basis. See the series "Introduce per NUMA node memory error
   statistics".

 - Mel Gorman has a second and hopefully final shot at fixing a CPU-hog
   regression in compaction via his series "Fix excessive CPU usage
   during compaction".

 - Christoph Hellwig does some vmalloc maintenance work in the series
   "cleanup vfree and vunmap".

 - Christoph Hellwig has removed block_device_operations.rw_page() in
   ths series "remove ->rw_page".

 - We get some maple_tree improvements and cleanups in Liam Howlett's
   series "VMA tree type safety and remove __vma_adjust()".

 - Suren Baghdasaryan has done some work on the maintainability of our
   vm_flags handling in the series "introduce vm_flags modifier
   functions".

 - Some pagemap cleanup and generalization work in Mike Rapoport's
   series "mm, arch: add generic implementation of pfn_valid() for
   FLATMEM" and "fixups for generic implementation of pfn_valid()"

 - Baoquan He has done some work to make /proc/vmallocinfo and
   /proc/kcore better represent the real state of things in his series
   "mm/vmalloc.c: allow vread() to read out vm_map_ram areas".

 - Jason Gunthorpe rationalized the GUP system's interface to the rest
   of the kernel in the series "Simplify the external interface for
   GUP".

 - SeongJae Park wishes to migrate people from DAMON's debugfs interface
   over to its sysfs interface. To support this, we'll temporarily be
   printing warnings when people use the debugfs interface. See the
   series "mm/damon: deprecate DAMON debugfs interface".

 - Andrey Konovalov provided the accurately named "lib/stackdepot: fixes
   and clean-ups" series.

 - Huang Ying has provided a dramatic reduction in migration's TLB flush
   IPI rates with the series "migrate_pages(): batch TLB flushing".

 - Arnd Bergmann has some objtool fixups in "objtool warning fixes".

* tag 'mm-stable-2023-02-20-13-37' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (505 commits)
  include/linux/migrate.h: remove unneeded externs
  mm/memory_hotplug: cleanup return value handing in do_migrate_range()
  mm/uffd: fix comment in handling pte markers
  mm: change to return bool for isolate_movable_page()
  mm: hugetlb: change to return bool for isolate_hugetlb()
  mm: change to return bool for isolate_lru_page()
  mm: change to return bool for folio_isolate_lru()
  objtool: add UACCESS exceptions for __tsan_volatile_read/write
  kmsan: disable ftrace in kmsan core code
  kasan: mark addr_has_metadata __always_inline
  mm: memcontrol: rename memcg_kmem_enabled()
  sh: initialize max_mapnr
  m68k/nommu: add missing definition of ARCH_PFN_OFFSET
  mm: percpu: fix incorrect size in pcpu_obj_full_size()
  maple_tree: reduce stack usage with gcc-9 and earlier
  mm: page_alloc: call panic() when memoryless node allocation fails
  mm: multi-gen LRU: avoid futile retries
  migrate_pages: move THP/hugetlb migration support check to simplify code
  migrate_pages: batch flushing TLB
  migrate_pages: share more code between _unmap and _move
  ...

10 files changed, 226 insertions, 33 deletions

diff --git a/mm/kasan/common.c b/mm/kasan/common.c
index 21e66d7f261d..b376a5d055e5 100644
--- a/mm/kasan/common.c
+++ b/mm/kasan/common.c
@@ -43,7 +43,7 @@ depot_stack_handle_t kasan_save_stack(gfp_t flags, bool can_alloc)
 	unsigned int nr_entries;
 
 	nr_entries = stack_trace_save(entries, ARRAY_SIZE(entries), 0);
-	return __stack_depot_save(entries, nr_entries, 0, flags, can_alloc);
+	return __stack_depot_save(entries, nr_entries, flags, can_alloc);
 }
 
 void kasan_set_track(struct kasan_track *track, gfp_t flags)
@@ -95,19 +95,24 @@ asmlinkage void kasan_unpoison_task_stack_below(const void *watermark)
 }
 #endif /* CONFIG_KASAN_STACK */
 
-void __kasan_unpoison_pages(struct page *page, unsigned int order, bool init)
+bool __kasan_unpoison_pages(struct page *page, unsigned int order, bool init)
 {
 	u8 tag;
 	unsigned long i;
 
 	if (unlikely(PageHighMem(page)))
-		return;
+		return false;
+
+	if (!kasan_sample_page_alloc(order))
+		return false;
 
 	tag = kasan_random_tag();
 	kasan_unpoison(set_tag(page_address(page), tag),
 		       PAGE_SIZE << order, init);
 	for (i = 0; i < (1 << order); i++)
 		page_kasan_tag_set(page + i, tag);
+
+	return true;
 }
 
 void __kasan_poison_pages(struct page *page, unsigned int order, bool init)
@@ -117,11 +122,6 @@ void __kasan_poison_pages(struct page *page, unsigned int order, bool init)
 			     KASAN_PAGE_FREE, init);
 }
 
-void __kasan_cache_create_kmalloc(struct kmem_cache *cache)
-{
-	cache->kasan_info.is_kmalloc = true;
-}
-
 void __kasan_poison_slab(struct slab *slab)
 {
 	struct page *page = slab_page(slab);
@@ -324,7 +324,7 @@ void * __must_check __kasan_slab_alloc(struct kmem_cache *cache,
 	kasan_unpoison(tagged_object, cache->object_size, init);
 
 	/* Save alloc info (if possible) for non-kmalloc() allocations. */
-	if (kasan_stack_collection_enabled() && !cache->kasan_info.is_kmalloc)
+	if (kasan_stack_collection_enabled() && !is_kmalloc_cache(cache))
 		kasan_save_alloc_info(cache, tagged_object, flags);
 
 	return tagged_object;
@@ -370,7 +370,7 @@ static inline void *____kasan_kmalloc(struct kmem_cache *cache,
 	 * Save alloc info (if possible) for kmalloc() allocations.
 	 * This also rewrites the alloc info when called from kasan_krealloc().
 	 */
-	if (kasan_stack_collection_enabled() && cache->kasan_info.is_kmalloc)
+	if (kasan_stack_collection_enabled() && is_kmalloc_cache(cache))
 		kasan_save_alloc_info(cache, (void *)object, flags);
 
 	/* Keep the tag that was set by kasan_slab_alloc(). */
diff --git a/mm/kasan/generic.c b/mm/kasan/generic.c
index cb762982c8ba..e5eef670735e 100644
--- a/mm/kasan/generic.c
+++ b/mm/kasan/generic.c
@@ -172,10 +172,8 @@ static __always_inline bool check_region_inline(unsigned long addr,
 	if (unlikely(addr + size < addr))
 		return !kasan_report(addr, size, write, ret_ip);
 
-	if (unlikely((void *)addr <
-		kasan_shadow_to_mem((void *)KASAN_SHADOW_START))) {
+	if (unlikely(!addr_has_metadata((void *)addr)))
 		return !kasan_report(addr, size, write, ret_ip);
-	}
 
 	if (likely(!memory_is_poisoned(addr, size)))
 		return true;
diff --git a/mm/kasan/hw_tags.c b/mm/kasan/hw_tags.c
index b22c4f461cb0..d1bcb0205327 100644
--- a/mm/kasan/hw_tags.c
+++ b/mm/kasan/hw_tags.c
@@ -59,6 +59,24 @@ EXPORT_SYMBOL_GPL(kasan_mode);
 /* Whether to enable vmalloc tagging. */
 DEFINE_STATIC_KEY_TRUE(kasan_flag_vmalloc);
 
+#define PAGE_ALLOC_SAMPLE_DEFAULT	1
+#define PAGE_ALLOC_SAMPLE_ORDER_DEFAULT	3
+
+/*
+ * Sampling interval of page_alloc allocation (un)poisoning.
+ * Defaults to no sampling.
+ */
+unsigned long kasan_page_alloc_sample = PAGE_ALLOC_SAMPLE_DEFAULT;
+
+/*
+ * Minimum order of page_alloc allocations to be affected by sampling.
+ * The default value is chosen to match both
+ * PAGE_ALLOC_COSTLY_ORDER and SKB_FRAG_PAGE_ORDER.
+ */
+unsigned int kasan_page_alloc_sample_order = PAGE_ALLOC_SAMPLE_ORDER_DEFAULT;
+
+DEFINE_PER_CPU(long, kasan_page_alloc_skip);
+
 /* kasan=off/on */
 static int __init early_kasan_flag(char *arg)
 {
@@ -122,6 +140,48 @@ static inline const char *kasan_mode_info(void)
 		return "sync";
 }
 
+/* kasan.page_alloc.sample=<sampling interval> */
+static int __init early_kasan_flag_page_alloc_sample(char *arg)
+{
+	int rv;
+
+	if (!arg)
+		return -EINVAL;
+
+	rv = kstrtoul(arg, 0, &kasan_page_alloc_sample);
+	if (rv)
+		return rv;
+
+	if (!kasan_page_alloc_sample || kasan_page_alloc_sample > LONG_MAX) {
+		kasan_page_alloc_sample = PAGE_ALLOC_SAMPLE_DEFAULT;
+		return -EINVAL;
+	}
+
+	return 0;
+}
+early_param("kasan.page_alloc.sample", early_kasan_flag_page_alloc_sample);
+
+/* kasan.page_alloc.sample.order=<minimum page order> */
+static int __init early_kasan_flag_page_alloc_sample_order(char *arg)
+{
+	int rv;
+
+	if (!arg)
+		return -EINVAL;
+
+	rv = kstrtouint(arg, 0, &kasan_page_alloc_sample_order);
+	if (rv)
+		return rv;
+
+	if (kasan_page_alloc_sample_order > INT_MAX) {
+		kasan_page_alloc_sample_order = PAGE_ALLOC_SAMPLE_ORDER_DEFAULT;
+		return -EINVAL;
+	}
+
+	return 0;
+}
+early_param("kasan.page_alloc.sample.order", early_kasan_flag_page_alloc_sample_order);
+
 /*
  * kasan_init_hw_tags_cpu() is called for each CPU.
  * Not marked as __init as a CPU can be hot-plugged after boot.
diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h
index 71c15438afcf..9377b0789edc 100644
--- a/mm/kasan/kasan.h
+++ b/mm/kasan/kasan.h
@@ -42,6 +42,10 @@ enum kasan_mode {
 
 extern enum kasan_mode kasan_mode __ro_after_init;
 
+extern unsigned long kasan_page_alloc_sample;
+extern unsigned int kasan_page_alloc_sample_order;
+DECLARE_PER_CPU(long, kasan_page_alloc_skip);
+
 static inline bool kasan_vmalloc_enabled(void)
 {
 	return static_branch_likely(&kasan_flag_vmalloc);
@@ -57,6 +61,24 @@ static inline bool kasan_sync_fault_possible(void)
 	return kasan_mode == KASAN_MODE_SYNC || kasan_mode == KASAN_MODE_ASYMM;
 }
 
+static inline bool kasan_sample_page_alloc(unsigned int order)
+{
+	/* Fast-path for when sampling is disabled. */
+	if (kasan_page_alloc_sample == 1)
+		return true;
+
+	if (order < kasan_page_alloc_sample_order)
+		return true;
+
+	if (this_cpu_dec_return(kasan_page_alloc_skip) < 0) {
+		this_cpu_write(kasan_page_alloc_skip,
+			       kasan_page_alloc_sample - 1);
+		return true;
+	}
+
+	return false;
+}
+
 #else /* CONFIG_KASAN_HW_TAGS */
 
 static inline bool kasan_async_fault_possible(void)
@@ -69,6 +91,11 @@ static inline bool kasan_sync_fault_possible(void)
 	return true;
 }
 
+static inline bool kasan_sample_page_alloc(unsigned int order)
+{
+	return true;
+}
+
 #endif /* CONFIG_KASAN_HW_TAGS */
 
 #ifdef CONFIG_KASAN_GENERIC
@@ -180,6 +207,7 @@ struct kasan_report_info {
 	void *first_bad_addr;
 	struct kmem_cache *cache;
 	void *object;
+	size_t alloc_size;
 
 	/* Filled in by the mode-specific reporting code. */
 	const char *bug_type;
@@ -269,7 +297,7 @@ static inline const void *kasan_shadow_to_mem(const void *shadow_addr)
 		<< KASAN_SHADOW_SCALE_SHIFT);
 }
 
-static inline bool addr_has_metadata(const void *addr)
+static __always_inline bool addr_has_metadata(const void *addr)
 {
 	return (kasan_reset_tag(addr) >=
 		kasan_shadow_to_mem((void *)KASAN_SHADOW_START));
@@ -288,7 +316,7 @@ bool kasan_check_range(unsigned long addr, size_t size, bool write,
 
 #else /* CONFIG_KASAN_GENERIC || CONFIG_KASAN_SW_TAGS */
 
-static inline bool addr_has_metadata(const void *addr)
+static __always_inline bool addr_has_metadata(const void *addr)
 {
 	return (is_vmalloc_addr(addr) || virt_addr_valid(addr));
 }
@@ -296,6 +324,7 @@ static inline bool addr_has_metadata(const void *addr)
 #endif /* CONFIG_KASAN_GENERIC || CONFIG_KASAN_SW_TAGS */
 
 void *kasan_find_first_bad_addr(void *addr, size_t size);
+size_t kasan_get_alloc_size(void *object, struct kmem_cache *cache);
 void kasan_complete_mode_report_info(struct kasan_report_info *info);
 void kasan_metadata_fetch_row(char *buffer, void *row);
 
diff --git a/mm/kasan/report.c b/mm/kasan/report.c
index 22598b20c7b7..89078f912827 100644
--- a/mm/kasan/report.c
+++ b/mm/kasan/report.c
@@ -231,33 +231,46 @@ static inline struct page *addr_to_page(const void *addr)
 	return NULL;
 }
 
-static void describe_object_addr(const void *addr, struct kmem_cache *cache,
-				 void *object)
+static void describe_object_addr(const void *addr, struct kasan_report_info *info)
 {
 	unsigned long access_addr = (unsigned long)addr;
-	unsigned long object_addr = (unsigned long)object;
-	const char *rel_type;
+	unsigned long object_addr = (unsigned long)info->object;
+	const char *rel_type, *region_state = "";
 	int rel_bytes;
 
 	pr_err("The buggy address belongs to the object at %px\n"
 	       " which belongs to the cache %s of size %d\n",
-		object, cache->name, cache->object_size);
+		info->object, info->cache->name, info->cache->object_size);
 
 	if (access_addr < object_addr) {
 		rel_type = "to the left";
 		rel_bytes = object_addr - access_addr;
-	} else if (access_addr >= object_addr + cache->object_size) {
+	} else if (access_addr >= object_addr + info->alloc_size) {
 		rel_type = "to the right";
-		rel_bytes = access_addr - (object_addr + cache->object_size);
+		rel_bytes = access_addr - (object_addr + info->alloc_size);
 	} else {
 		rel_type = "inside";
 		rel_bytes = access_addr - object_addr;
 	}
 
+	/*
+	 * Tag-Based modes use the stack ring to infer the bug type, but the
+	 * memory region state description is generated based on the metadata.
+	 * Thus, defining the region state as below can contradict the metadata.
+	 * Fixing this requires further improvements, so only infer the state
+	 * for the Generic mode.
+	 */
+	if (IS_ENABLED(CONFIG_KASAN_GENERIC)) {
+		if (strcmp(info->bug_type, "slab-out-of-bounds") == 0)
+			region_state = "allocated ";
+		else if (strcmp(info->bug_type, "slab-use-after-free") == 0)
+			region_state = "freed ";
+	}
+
 	pr_err("The buggy address is located %d bytes %s of\n"
-	       " %d-byte region [%px, %px)\n",
-		rel_bytes, rel_type, cache->object_size, (void *)object_addr,
-		(void *)(object_addr + cache->object_size));
+	       " %s%zu-byte region [%px, %px)\n",
+	       rel_bytes, rel_type, region_state, info->alloc_size,
+	       (void *)object_addr, (void *)(object_addr + info->alloc_size));
 }
 
 static void describe_object_stacks(struct kasan_report_info *info)
@@ -279,7 +292,7 @@ static void describe_object(const void *addr, struct kasan_report_info *info)
 {
 	if (kasan_stack_collection_enabled())
 		describe_object_stacks(info);
-	describe_object_addr(addr, info->cache, info->object);
+	describe_object_addr(addr, info);
 }
 
 static inline bool kernel_or_module_addr(const void *addr)
@@ -436,6 +449,12 @@ static void complete_report_info(struct kasan_report_info *info)
 	if (slab) {
 		info->cache = slab->slab_cache;
 		info->object = nearest_obj(info->cache, slab, addr);
+
+		/* Try to determine allocation size based on the metadata. */
+		info->alloc_size = kasan_get_alloc_size(info->object, info->cache);
+		/* Fallback to the object size if failed. */
+		if (!info->alloc_size)
+			info->alloc_size = info->cache->object_size;
 	} else
 		info->cache = info->object = NULL;
 
diff --git a/mm/kasan/report_generic.c b/mm/kasan/report_generic.c
index 043c94b04605..87d39bc0a673 100644
--- a/mm/kasan/report_generic.c
+++ b/mm/kasan/report_generic.c
@@ -43,6 +43,34 @@ void *kasan_find_first_bad_addr(void *addr, size_t size)
 	return p;
 }
 
+size_t kasan_get_alloc_size(void *object, struct kmem_cache *cache)
+{
+	size_t size = 0;
+	u8 *shadow;
+
+	/*
+	 * Skip the addr_has_metadata check, as this function only operates on
+	 * slab memory, which must have metadata.
+	 */
+
+	/*
+	 * The loop below returns 0 for freed objects, for which KASAN cannot
+	 * calculate the allocation size based on the metadata.
+	 */
+	shadow = (u8 *)kasan_mem_to_shadow(object);
+	while (size < cache->object_size) {
+		if (*shadow == 0)
+			size += KASAN_GRANULE_SIZE;
+		else if (*shadow >= 1 && *shadow <= KASAN_GRANULE_SIZE - 1)
+			return size + *shadow;
+		else
+			return size;
+		shadow++;
+	}
+
+	return cache->object_size;
+}
+
 static const char *get_shadow_bug_type(struct kasan_report_info *info)
 {
 	const char *bug_type = "unknown-crash";
@@ -79,9 +107,11 @@ static const char *get_shadow_bug_type(struct kasan_report_info *info)
 		bug_type = "stack-out-of-bounds";
 		break;
 	case KASAN_PAGE_FREE:
+		bug_type = "use-after-free";
+		break;
 	case KASAN_SLAB_FREE:
 	case KASAN_SLAB_FREETRACK:
-		bug_type = "use-after-free";
+		bug_type = "slab-use-after-free";
 		break;
 	case KASAN_ALLOCA_LEFT:
 	case KASAN_ALLOCA_RIGHT:
diff --git a/mm/kasan/report_hw_tags.c b/mm/kasan/report_hw_tags.c
index f3d3be614e4b..32e80f78de7d 100644
--- a/mm/kasan/report_hw_tags.c
+++ b/mm/kasan/report_hw_tags.c
@@ -17,10 +17,43 @@
 
 void *kasan_find_first_bad_addr(void *addr, size_t size)
 {
-	/* Return the same value regardless of whether addr_has_metadata(). */
+	/*
+	 * Hardware Tag-Based KASAN only calls this function for normal memory
+	 * accesses, and thus addr points precisely to the first bad address
+	 * with an invalid (and present) memory tag. Therefore:
+	 * 1. Return the address as is without walking memory tags.
+	 * 2. Skip the addr_has_metadata check.
+	 */
 	return kasan_reset_tag(addr);
 }
 
+size_t kasan_get_alloc_size(void *object, struct kmem_cache *cache)
+{
+	size_t size = 0;
+	int i = 0;
+	u8 memory_tag;
+
+	/*
+	 * Skip the addr_has_metadata check, as this function only operates on
+	 * slab memory, which must have metadata.
+	 */
+
+	/*
+	 * The loop below returns 0 for freed objects, for which KASAN cannot
+	 * calculate the allocation size based on the metadata.
+	 */
+	while (size < cache->object_size) {
+		memory_tag = hw_get_mem_tag(object + i * KASAN_GRANULE_SIZE);
+		if (memory_tag != KASAN_TAG_INVALID)
+			size += KASAN_GRANULE_SIZE;
+		else
+			return size;
+		i++;
+	}
+
+	return cache->object_size;
+}
+
 void kasan_metadata_fetch_row(char *buffer, void *row)
 {
 	int i;
diff --git a/mm/kasan/report_sw_tags.c b/mm/kasan/report_sw_tags.c
index 7a26397297ed..8b1f5a73ee6d 100644
--- a/mm/kasan/report_sw_tags.c
+++ b/mm/kasan/report_sw_tags.c
@@ -45,6 +45,32 @@ void *kasan_find_first_bad_addr(void *addr, size_t size)
 	return p;
 }
 
+size_t kasan_get_alloc_size(void *object, struct kmem_cache *cache)
+{
+	size_t size = 0;
+	u8 *shadow;
+
+	/*
+	 * Skip the addr_has_metadata check, as this function only operates on
+	 * slab memory, which must have metadata.
+	 */
+
+	/*
+	 * The loop below returns 0 for freed objects, for which KASAN cannot
+	 * calculate the allocation size based on the metadata.
+	 */
+	shadow = (u8 *)kasan_mem_to_shadow(object);
+	while (size < cache->object_size) {
+		if (*shadow != KASAN_TAG_INVALID)
+			size += KASAN_GRANULE_SIZE;
+		else
+			return size;
+		shadow++;
+	}
+
+	return cache->object_size;
+}
+
 void kasan_metadata_fetch_row(char *buffer, void *row)
 {
 	memcpy(buffer, kasan_mem_to_shadow(row), META_BYTES_PER_ROW);
diff --git a/mm/kasan/report_tags.c b/mm/kasan/report_tags.c
index ecede06ef374..8b8bfdb3cfdb 100644
--- a/mm/kasan/report_tags.c
+++ b/mm/kasan/report_tags.c
@@ -89,7 +89,7 @@ void kasan_complete_mode_report_info(struct kasan_report_info *info)
 			 * a use-after-free.
 			 */
 			if (!info->bug_type)
-				info->bug_type = "use-after-free";
+				info->bug_type = "slab-use-after-free";
 		} else {
 			/* Second alloc of the same object. Give up. */
 			if (alloc_found)
diff --git a/mm/kasan/sw_tags.c b/mm/kasan/sw_tags.c
index a3afaf2ad1b1..30da65fa02a1 100644
--- a/mm/kasan/sw_tags.c
+++ b/mm/kasan/sw_tags.c
@@ -106,10 +106,8 @@ bool kasan_check_range(unsigned long addr, size_t size, bool write,
 		return true;
 
 	untagged_addr = kasan_reset_tag((const void *)addr);
-	if (unlikely(untagged_addr <
-			kasan_shadow_to_mem((void *)KASAN_SHADOW_START))) {
+	if (unlikely(!addr_has_metadata(untagged_addr)))
 		return !kasan_report(addr, size, write, ret_ip);
-	}
 	shadow_first = kasan_mem_to_shadow(untagged_addr);
 	shadow_last = kasan_mem_to_shadow(untagged_addr + size - 1);
 	for (shadow = shadow_first; shadow <= shadow_last; shadow++) {
@@ -127,7 +125,7 @@ bool kasan_byte_accessible(const void *addr)
 	void *untagged_addr = kasan_reset_tag(addr);
 	u8 shadow_byte;
 
-	if (untagged_addr < kasan_shadow_to_mem((void *)KASAN_SHADOW_START))
+	if (!addr_has_metadata(untagged_addr))
 		return false;
 
 	shadow_byte = READ_ONCE(*(u8 *)kasan_mem_to_shadow(untagged_addr));