mm/kasan: get rid of ->alloc_size in struct kasan_alloc_meta

Size of slab object already stored in cache->object_size. Note, that kmalloc() internally rounds up size of allocation, so object_size may be not equal to alloc_size, but, usually we don't need to know the exact size of allocated object. In case if we need that information, we still can figure it out from the report. The dump of shadow memory allows to identify the end of allocated memory, and thereby the exact allocation size. Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Andrey Ryabinin <[email protected]> Cc: Alexander Potapenko <[email protected]> Cc: Dmitry Vyukov <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
arthurschreiber · Aug 2, 2016 · 47b5c2a · 47b5c2a
1 parent f7376ae
commit 47b5c2a
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Showing 3 changed files with 4 additions and 8 deletions.
diff --git a/mm/kasan/kasan.c b/mm/kasan/kasan.c
@@ -584,7 +584,6 @@ void kasan_kmalloc(struct kmem_cache *cache, const void *object, size_t size,
 			get_alloc_info(cache, object);
 
 		alloc_info->state = KASAN_STATE_ALLOC;
-		alloc_info->alloc_size = size;
 		set_track(&alloc_info->track, flags);
 	}
 }

diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h
@@ -75,8 +75,7 @@ struct kasan_track {
 
 struct kasan_alloc_meta {
 	struct kasan_track track;
-	u32 state : 2;	/* enum kasan_state */
-	u32 alloc_size : 30;
+	u32 state;
 };
 
 struct qlist_node {

diff --git a/mm/kasan/report.c b/mm/kasan/report.c
@@ -136,23 +136,21 @@ static void kasan_object_err(struct kmem_cache *cache, struct page *page,
 	struct kasan_free_meta *free_info;
 
 	dump_stack();
-	pr_err("Object at %p, in cache %s\n", object, cache->name);
+	pr_err("Object at %p, in cache %s size: %d\n", object, cache->name,
+		cache->object_size);
+
 	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:
 	case KASAN_STATE_QUARANTINE:
-		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);