On 02/02/2016 08:34 AM, Andrew Morton wrote: > On Wed, 27 Jan 2016 19:25:06 +0100 Alexander Potapenko <[email protected]> > wrote: > >> depending on which allocator (SLAB or SLUB) is being used >> >> ... >> >> --- a/lib/test_kasan.c >> +++ b/lib/test_kasan.c >> @@ -68,7 +68,22 @@ static noinline void __init kmalloc_node_oob_right(void) >> static noinline void __init kmalloc_large_oob_right(void) >> { >> char *ptr; >> - size_t size = KMALLOC_MAX_CACHE_SIZE + 10; >> + size_t size; >> + >> + if (KMALLOC_MAX_CACHE_SIZE == KMALLOC_MAX_SIZE) { >> + /* >> + * We're using the SLAB allocator. Allocate a chunk that fits >> + * into a slab. >> + */ >> + size = KMALLOC_MAX_CACHE_SIZE - 256; >> + } else { >> + /* >> + * KMALLOC_MAX_SIZE > KMALLOC_MAX_CACHE_SIZE. >> + * We're using the SLUB allocator. Allocate a chunk that does >> + * not fit into a slab to trigger the page allocator. >> + */ >> + size = KMALLOC_MAX_CACHE_SIZE + 10; >> + } > > This seems a weird way of working out whether we're using SLAB or SLUB. > > Can't we use, umm, #ifdef CONFIG_SLAB? If not that then let's cook up > something standardized rather than a weird just-happens-to-work like > this. >
Actually it would be simpler to not use KMALLOC_MAX_CACHE_SIZE at all. Simply replace it with 2 or 3 PAGE_SIZEs.
