On Fri, Mar 3, 2017 at 2:50 PM, Andrey Ryabinin <aryabinin@xxxxxxxxxxxxx> wrote: > > > On 03/02/2017 07:38 PM, Arnd Bergmann wrote: >> When CONFIG_KASAN is set, we can run into some code that uses incredible >> amounts of kernel stack: >> >> drivers/staging/dgnc/dgnc_neo.c:1056:1: error: the frame size of 11112 bytes is larger than 2048 bytes [-Werror=frame-larger-than=] >> drivers/media/i2c/cx25840/cx25840-core.c:4960:1: error: the frame size of 94000 bytes is larger than 2048 bytes [-Werror=frame-larger-than=] >> drivers/media/dvb-frontends/stv090x.c:3430:1: error: the frame size of 5312 bytes is larger than 3072 bytes [-Werror=frame-larger-than=] >> >> This happens when a sanitizer uses stack memory each time an inline function >> gets called. This introduces a new annotation for those functions to make >> them either 'inline' or 'noinline' dependning on the CONFIG_KASAN symbol. >> >> Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx> >> --- >> include/linux/compiler.h | 11 +++++++++++ >> 1 file changed, 11 insertions(+) >> >> diff --git a/include/linux/compiler.h b/include/linux/compiler.h >> index f8110051188f..56b90897a459 100644 >> --- a/include/linux/compiler.h >> +++ b/include/linux/compiler.h >> @@ -416,6 +416,17 @@ static __always_inline void __write_once_size(volatile void *p, void *res, int s >> */ >> #define noinline_for_stack noinline >> >> +/* >> + * CONFIG_KASAN can lead to extreme stack usage with certain patterns when >> + * one function gets inlined many times and each instance requires a stack >> + * ckeck. >> + */ >> +#ifdef CONFIG_KASAN >> +#define noinline_for_kasan noinline __maybe_unused > > > noinline_iff_kasan might be a better name. noinline_for_kasan gives the impression > that we always noinline function for the sake of kasan, while noinline_iff_kasan > clearly indicates that function is noinline only if kasan is used. FWIW we may be facing the same problem with other compiler-based tools, e.g. KMSAN (which isn't there yet). So it might be better to choose a macro name that doesn't use the name "KASAN". E.g. noinline_iff_memtool (or noinline_iff_memory_tool if that's not too long). WDYT? >> +#else >> +#define noinline_for_kasan inline >> +#endif >> + >> #ifndef __always_inline >> #define __always_inline inline >> #endif >> > > -- > You received this message because you are subscribed to the Google Groups "kasan-dev" group. > To unsubscribe from this group and stop receiving emails from it, send an email to kasan-dev+unsubscribe@xxxxxxxxxxxxxxxx. > To post to this group, send email to kasan-dev@xxxxxxxxxxxxxxxx. > To view this discussion on the web visit https://groups.google.com/d/msgid/kasan-dev/7e7a62de-3b79-6044-72fa-4ade418953d1%40virtuozzo.com. > For more options, visit https://groups.google.com/d/optout. -- Alexander Potapenko Software Engineer Google Germany GmbH Erika-Mann-Straße, 33 80636 München Geschäftsführer: Matthew Scott Sucherman, Paul Terence Manicle Registergericht und -nummer: Hamburg, HRB 86891 Sitz der Gesellschaft: Hamburg
