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Commit db429f16 authored by Andrey Konovalov's avatar Andrey Konovalov Committed by Linus Torvalds
Browse files

kasan: simplify address description logic 

Simplify logic for describing a memory address.  Add addr_to_page()
helper function.

Makes the code easier to follow.

Link: http://lkml.kernel.org/r/20170302134851.101218-5-andreyknvl@google.com


Signed-off-by: default avatarAndrey Konovalov <andreyknvl@google.com>
Acked-by: default avatarDmitry Vyukov <dvyukov@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Alexander Potapenko <glider@google.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent b6b72f49

mm/kasan/report.c

+21 −16
Original line number Diff line number Diff line
@@ -190,11 +190,18 @@ static void print_track(struct kasan_track *track, const char *prefix) 
	}

}



static void kasan_object_err(struct kmem_cache *cache, void *object)

static struct page *addr_to_page(const void *addr)

{

	if ((addr >= (void *)PAGE_OFFSET) &&

			(addr < high_memory))

		return virt_to_head_page(addr);

	return NULL;

}



static void describe_object(struct kmem_cache *cache, void *object)

{

	struct kasan_alloc_meta *alloc_info = get_alloc_info(cache, object);



	dump_stack();

	pr_err("Object at %p, in cache %s size: %d\n", object, cache->name,

		cache->object_size);
@@ -213,34 +220,32 @@ void kasan_report_double_free(struct kmem_cache *cache, void *object, 
	kasan_start_report(&flags);

	pr_err("BUG: Double free or freeing an invalid pointer\n");

	pr_err("Unexpected shadow byte: 0x%hhX\n", shadow);

	kasan_object_err(cache, object);

	dump_stack();

	describe_object(cache, object);

	kasan_end_report(&flags);

}



static void print_address_description(struct kasan_access_info *info)

{

	const void *addr = info->access_addr;

	struct page *page = addr_to_page(addr);



	if ((addr >= (void *)PAGE_OFFSET) &&

		(addr < high_memory)) {

		struct page *page = virt_to_head_page(addr);

	if (page)

		dump_page(page, "kasan: bad access detected");



		if (PageSlab(page)) {

			void *object;

	dump_stack();



	if (page && PageSlab(page)) {

		struct kmem_cache *cache = page->slab_cache;

			object = nearest_obj(cache, page,

						(void *)info->access_addr);

			kasan_object_err(cache, object);

			return;

		}

		dump_page(page, "kasan: bad access detected");

		void *object = nearest_obj(cache, page,	(void *)addr);



		describe_object(cache, object);

	}



	if (kernel_or_module_addr(addr)) {

		if (!init_task_stack_addr(addr))

			pr_err("Address belongs to variable %pS\n", addr);

	}

	dump_stack();

}



static bool row_is_guilty(const void *row, const void *guilty)