On Mon, Feb 29, 2016 at 03:44:40PM +0100, Ard Biesheuvel wrote: > @@ -404,6 +404,12 @@ void __init mem_init(void) > BUILD_BUG_ON(TASK_SIZE_32 > TASK_SIZE_64); > #endif > > + /* > + * Make sure we chose the upper bound of sizeof(struct page) > + * correctly. > + */ > + BUILD_BUG_ON(sizeof(struct page) > (1 << STRUCT_PAGE_MAX_SHIFT)); Since with the vmemmap fix you already assume that PAGE_OFFSET is half of the VA space, we should add another check on PAGE_OFFSET != UL(0xffffffffffffffff) << (VA_BITS - 1), just in case someone thinks they could map a bit of extra RAM without going for a larger VA. -- Catalin -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>