On Tue, Dec 08, 2020 at 11:01:57PM +1100, Stephen Rothwell wrote:
> Hi Stephen,
>
> On Fri, 4 Dec 2020 21:00:00 +1100 Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx> wrote:
> >
> > Hi all,
> >
> > After merging the akpm tree, today's linux-next build (powerpc
> > allyesconfig) produced warnings like this:
> >
> > ld: warning: orphan section `.data..Lubsan_data177' from `arch/powerpc/oprofile/op_model_pa6t.o' being placed in section `.data..Lubsan_data177'
> >
> > (lots of these latter ones)
>
> 781584 of them today!
>
> > I don't know what produced these, but it is in the akpm-current or
> > akpm trees.
>
> Presumably the result of commit
>
> 186c3e18dba3 ("ubsan: enable for all*config builds")
>
> from the akpm-current tree.
>
> arch/powerpc/kernel/vmlinux.lds.S has:
>
> #ifdef CONFIG_PPC32
> .data : AT(ADDR(.data) - LOAD_OFFSET) {
> DATA_DATA
> #ifdef CONFIG_UBSAN
> *(.data..Lubsan_data*)
> *(.data..Lubsan_type*)
> #endif
> *(.data.rel*)
> *(SDATA_MAIN)
>
> added by commit
>
> beba24ac5913 ("powerpc/32: Add .data..Lubsan_data*/.data..Lubsan_type* sections explicitly")
>
> in 2018, but no equivalent for 64 bit.
>
> I will try the following patch tomorrow:
>
> From: Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx>
> Date: Tue, 8 Dec 2020 22:58:24 +1100
> Subject: [PATCH] powerpc: Add .data..Lubsan_data*/.data..Lubsan_type* sections explicitly
>
> Similarly to commit
>
> beba24ac5913 ("powerpc/32: Add .data..Lubsan_data*/.data..Lubsan_type* sections explicitly")
>
> since CONFIG_UBSAN bits can now be enabled for all*config.
>
> Signed-off-by: Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx>
> ---
> arch/powerpc/kernel/vmlinux.lds.S | 4 ++++
> 1 file changed, 4 insertions(+)
>
> diff --git a/arch/powerpc/kernel/vmlinux.lds.S b/arch/powerpc/kernel/vmlinux.lds.S
> index 3b4c26e94328..0318ba436f34 100644
> --- a/arch/powerpc/kernel/vmlinux.lds.S
> +++ b/arch/powerpc/kernel/vmlinux.lds.S
> @@ -296,6 +296,10 @@ SECTIONS
> #else
> .data : AT(ADDR(.data) - LOAD_OFFSET) {
> DATA_DATA
> +#ifdef CONFIG_UBSAN
> + *(.data..Lubsan_data*)
> + *(.data..Lubsan_type*)
> +#endif
> *(.data.rel*)
> *(.toc1)
> *(.branch_lt)
> --
> 2.29.2
>
> --
> Cheers,
> Stephen Rothwell
Reviewed-by: Kees Cook <keescook@xxxxxxxxxxxx>
Thanks for figuring this one out. :) Andrew, can you add this to your
ubsan patch stack, or do you want me to resend it to you directly?
--
Kees Cook
