On Mon, Dec 4, 2017 at 8:14 AM, Andrey Ryabinin <aryabinin@virtuozzo.com>
wrote:

>
> On 12/02/2017 12:36 AM, Paul Lawrence wrote:
> >
>
> Missing:
>         From: Andrey Ryabinin <aryabinin@virtuozzo.com>
>
> Please, don't change authorship of the patches.


​Sorry - I'll fix this when I next upload.​

>
> > LLVM doesn't understand GCC-style paramters ("--param asan-foo=bar"),
> > thus we currently we don't use inline/globals/stack instrumentation
> > when building the kernel with clang.
> >
> > Add support for LLVM-style parameters ("-mllvm -asan-foo=bar") to
> > enable all KASAN features.
> >
> > Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
> > ---
> >  scripts/Makefile.kasan | 29 ++++++++++++++++++-----------
> >  1 file changed, 18 insertions(+), 11 deletions(-)
> >
> > diff --git a/scripts/Makefile.kasan b/scripts/Makefile.kasan
> > index 1ce7115aa499..7c00be9216f4 100644
> > --- a/scripts/Makefile.kasan
> > +++ b/scripts/Makefile.kasan
> > @@ -10,10 +10,7 @@ KASAN_SHADOW_OFFSET ?= $(CONFIG_KASAN_SHADOW_OFFSET)
> >
>
>
>
> > +   # -fasan-shadow-offset fails without -fsanitize
> > +   CFLAGS_KASAN_SHADOW := $(call cc-option, -fsanitize=kernel-address \
> > +                     -fasan-shadow-offset=$(KASAN_SHADOW_OFFSET), \
> > +                     $(call cc-option, -fsanitize=kernel-address \
> > +                     -mllvm -asan-mapping-offset=$(KASAN_
> SHADOW_OFFSET)))
> > +
> > +   ifeq ("$(CFLAGS_KASAN_SHADOW)"," ")
>
> This not how it was in my original patch. Why you changed this?
> Condition is always false now, so it breaks kasan with 4.9.x gcc.
>

​I had the opposite problem - CFLAGS_KASAN_SHADOW is always at least a
space, and the
original condition would always be false, which is why I changed it.​ On
investigation, I found
that if the line was split it would always be a space -
$(false,whatever,empty-string) would be
truly empty, but if the line was split after the second comma it would be
one space. Is this a
difference in our make systems?


> > +      CFLAGS_KASAN := $(CFLAGS_KASAN_MINIMAL)
> > +   else
> > +      # Now add all the compiler specific options that are valid
> standalone
> > +      CFLAGS_KASAN := $(CFLAGS_KASAN_SHADOW) \
> > +     $(call cc-param,asan-globals=1) \
>