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

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.comSigned-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
...@@ -190,11 +190,18 @@ static void print_track(struct kasan_track *track, const char *prefix) ...@@ -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); 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, pr_err("Object at %p, in cache %s size: %d\n", object, cache->name,
cache->object_size); cache->object_size);
...@@ -213,34 +220,32 @@ void kasan_report_double_free(struct kmem_cache *cache, void *object, ...@@ -213,34 +220,32 @@ void kasan_report_double_free(struct kmem_cache *cache, void *object,
kasan_start_report(&flags); kasan_start_report(&flags);
pr_err("BUG: Double free or freeing an invalid pointer\n"); pr_err("BUG: Double free or freeing an invalid pointer\n");
pr_err("Unexpected shadow byte: 0x%hhX\n", shadow); pr_err("Unexpected shadow byte: 0x%hhX\n", shadow);
kasan_object_err(cache, object); dump_stack();
describe_object(cache, object);
kasan_end_report(&flags); kasan_end_report(&flags);
} }
static void print_address_description(struct kasan_access_info *info) static void print_address_description(struct kasan_access_info *info)
{ {
const void *addr = info->access_addr; const void *addr = info->access_addr;
struct page *page = addr_to_page(addr);
if ((addr >= (void *)PAGE_OFFSET) && if (page)
(addr < high_memory)) {
struct page *page = virt_to_head_page(addr);
if (PageSlab(page)) {
void *object;
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"); dump_page(page, "kasan: bad access detected");
dump_stack();
if (page && PageSlab(page)) {
struct kmem_cache *cache = page->slab_cache;
void *object = nearest_obj(cache, page, (void *)addr);
describe_object(cache, object);
} }
if (kernel_or_module_addr(addr)) { if (kernel_or_module_addr(addr)) {
if (!init_task_stack_addr(addr)) if (!init_task_stack_addr(addr))
pr_err("Address belongs to variable %pS\n", addr); pr_err("Address belongs to variable %pS\n", addr);
} }
dump_stack();
} }
static bool row_is_guilty(const void *row, const void *guilty) static bool row_is_guilty(const void *row, const void *guilty)
......
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