Re: [PATCH] powerpc/prom_init: Add memset as valid external symbol if CONFIG_KASAN=y

[Christophe Leroy]

Le 19/06/2022 à 08:45, Christophe Leroy a écrit :
> Le 19/06/2022 à 05:52, Guenter Roeck a écrit :
> > If CONFIG_KASAN=y, powerpc:allmodconfig fails to build with the following
> > error.
> >
> > Error: External symbol 'memset' referenced from prom_init.c
> >
> > The problem was introduced with commit 41b7a347bf14 ("powerpc: Book3S
> > 64-bit outline-only KASAN support"). So far, with CONFIG_KASAN=y, only
> > __memset was accepted as valid external symbol in prom_init_check.sh.
> > Add memset as well to fix the problem.
>
> No way. It is way too early to use the instrumented version of memset().

See commit 26deb04342e3 ("powerpc: prepare string/mem functions for 
KASAN") for more details

> Did you try with the patch I sent ?
>
> https://patchwork.ozlabs.org/project/linuxppc-dev/patch/3802811f7cf94f730be44688539c01bba3a3b5c0.1654875808.git.christophe.leroy@xxxxxxxxxx/
>
> Thanks
> Christophe
>
> > Fixes: 41b7a347bf14 ("powerpc: Book3S 64-bit outline-only KASAN support")
> > Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
> > Cc: Daniel Axtens <dja@xxxxxxxxxx>
> > Signed-off-by: Guenter Roeck <linux@xxxxxxxxxxxx>
> > ---
> >    arch/powerpc/kernel/prom_init_check.sh | 2 +-
> >    1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/arch/powerpc/kernel/prom_init_check.sh b/arch/powerpc/kernel/prom_init_check.sh
> > index b183ab9c5107..787142b5dd26 100644
> > --- a/arch/powerpc/kernel/prom_init_check.sh
> > +++ b/arch/powerpc/kernel/prom_init_check.sh
> > @@ -16,7 +16,7 @@
> >    grep "^CONFIG_KASAN=y$" .config >/dev/null
> >    if [ $? -eq 0 ]
> >    then
> > -	MEM_FUNCS="__memcpy __memset"
> > +	MEM_FUNCS="__memcpy __memset memset"
> >    else
> >    	MEM_FUNCS="memcpy memset"
> >    fi