On Fri, Jan 8, 2021 at 7:56 PM Andrey Konovalov <andreyknvl@xxxxxxxxxx> wrote: > On Fri, Jan 8, 2021 at 5:09 AM Walter Wu <walter-zh.wu@xxxxxxxxxxxx> wrote: > > @@ -2,6 +2,12 @@ > > CFLAGS_KASAN_NOSANITIZE := -fno-builtin > > KASAN_SHADOW_OFFSET ?= $(CONFIG_KASAN_SHADOW_OFFSET) > > > > +ifdef CONFIG_KASAN_STACK > > + stack_enable := 1 > > +else > > + stack_enable := 0 > > +endif > > + > > AFAIR, Arnd wanted to avoid having KASAN_STACK to be enabled by > default when compiling with Clang, since Clang instrumentation leads > to very large kernel stacks, which, in turn, lead to compile-time > warnings. What I don't remember is why there are two configs. > > Arnd, is that correct? What was the reason behind having two configs? I think I just considered it cleaner than defining the extra variable in the Makefile at the time, as this was the only place that referenced CONFIG_KASAN_STACK. The '#if CONFIG_KASAN_STACK' (rather than #ifdef) that got added later do make my version more confusing though, so I agree that Walter's second patch improves it. Acked-by: Arnd Bergmann <arnd@xxxxxxxx> On a related note: do you have any hope that clang will ever fix https://bugs.llvm.org/show_bug.cgi?id=38809 and KASAN_STACK can be enabled by default on clang without risking stack overflows? Arnd
