1 files changed, 26 insertions, 0 deletions
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);