mm, kasan: SLAB support

Add KASAN hooks to SLAB allocator.

This patch is based on the "mm: kasan: unified support for SLUB and SLAB
allocators" patch originally prepared by Dmitry Chernenkov.

Signed-off-by: Alexander Potapenko <glider@google.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Andrey Konovalov <adech.fo@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Konstantin Serebryany <kcc@google.com>
Cc: Dmitry Chernenkov <dmitryc@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 43 insertions, 11 deletions

diff --git a/mm/kasan/report.c b/mm/kasan/report.c
index 745aa8f36028..3e3385cc97ac 100644
--- a/mm/kasan/report.c
+++ b/mm/kasan/report.c
@@ -115,6 +115,46 @@ static inline bool init_task_stack_addr(const void *addr)
 			sizeof(init_thread_union.stack));
 }
 
+#ifdef CONFIG_SLAB
+static void print_track(struct kasan_track *track)
+{
+	pr_err("PID = %u, CPU = %u, timestamp = %lu\n", track->pid,
+	       track->cpu, (unsigned long)track->when);
+}
+
+static void object_err(struct kmem_cache *cache, struct page *page,
+			void *object, char *unused_reason)
+{
+	struct kasan_alloc_meta *alloc_info = get_alloc_info(cache, object);
+	struct kasan_free_meta *free_info;
+
+	dump_stack();
+	pr_err("Object at %p, in cache %s\n", object, cache->name);
+	if (!(cache->flags & SLAB_KASAN))
+		return;
+	switch (alloc_info->state) {
+	case KASAN_STATE_INIT:
+		pr_err("Object not allocated yet\n");
+		break;
+	case KASAN_STATE_ALLOC:
+		pr_err("Object allocated with size %u bytes.\n",
+		       alloc_info->alloc_size);
+		pr_err("Allocation:\n");
+		print_track(&alloc_info->track);
+		break;
+	case KASAN_STATE_FREE:
+		pr_err("Object freed, allocated with size %u bytes\n",
+		       alloc_info->alloc_size);
+		free_info = get_free_info(cache, object);
+		pr_err("Allocation:\n");
+		print_track(&alloc_info->track);
+		pr_err("Deallocation:\n");
+		print_track(&free_info->track);
+		break;
+	}
+}
+#endif
+
 static void print_address_description(struct kasan_access_info *info)
 {
 	const void *addr = info->access_addr;
@@ -126,17 +166,10 @@ static void print_address_description(struct kasan_access_info *info)
 		if (PageSlab(page)) {
 			void *object;
 			struct kmem_cache *cache = page->slab_cache;
-			void *last_object;
-
-			object = virt_to_obj(cache, page_address(page), addr);
-			last_object = page_address(page) +
-				page->objects * cache->size;
-
-			if (unlikely(object > last_object))
-				object = last_object; /* we hit into padding */
-
+			object = nearest_obj(cache, page,
+						(void *)info->access_addr);
 			object_err(cache, page, object,
-				"kasan: bad access detected");
+					"kasan: bad access detected");
 			return;
 		}
 		dump_page(page, "kasan: bad access detected");
@@ -146,7 +179,6 @@ static void print_address_description(struct kasan_access_info *info)
 		if (!init_task_stack_addr(addr))
 			pr_err("Address belongs to variable %pS\n", addr);
 	}
-
 	dump_stack();
 }