On 01/19/2018 08:58 PM, Andrey Konovalov wrote: > With KASAN enabled the kernel has two different memset() functions, one > with KASAN checks (memset) and one without (__memset). KASAN uses some > macro tricks to use the proper version where required. For example memset() > calls in mm/slub.c are without KASAN checks, since they operate on poisoned > slab object metadata. > > The issue is that clang emits memset() calls even when there is no memset() > in the source code. They get linked with improper memset() implementation > and the kernel fails to boot due to a huge amount of KASAN reports during > early boot stages. > So how did you observe this? Why am I not seeing this problem? > The solution is to add -fno-builtin flag for files with KASAN_SANITIZE := n > marker. > I'm not sure I understand how is this solves the problem. And what clang does instead of memset()? Does it inlines memset()? But according to GCC's man (clang's man is very vague about this) -fno-builtin should do exactly the opposite - prevent inlining builtin functions and always generate a function call. -- To unsubscribe from this list: send the line "unsubscribe linux-kbuild" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
