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Date:   Mon, 16 Jan 2023 13:36:34 +0100 (CET)
From:   Geert Uytterhoeven <geert@linux-m68k.org>
To:     linux-kernel@vger.kernel.org
cc:     linux-s390@vger.kernel.org
Subject: Re: Build regressions/improvements in v6.2-rc4
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On Mon, 16 Jan 2023, Geert Uytterhoeven wrote:
> JFYI, when comparing v6.2-rc4[1] to v6.2-rc3-8-g1fe4fd6f5cad346e[3], the summaries are:
>  - build errors: +1/-5

   + /kisskb/src/include/linux/fortify-string.h: error: '__builtin_memcpy' reading 128 bytes from a region of size 0 [-Werror=stringop-overread]:  => 57:33

s390x-gcc11/s390-allmodconfig

/kisskb/src/arch/s390/kernel/setup.c: In function 'setup_lowcore_dat_on':
/kisskb/src/include/linux/fortify-string.h:57:33: error: '__builtin_memcpy' reading 128 bytes from a region of size 0 [-Werror=stringop-overread]
    57 | #define __underlying_memcpy     __builtin_memcpy
       |                                 ^
/kisskb/src/include/linux/fortify-string.h:578:9: note: in expansion of macro '__underlying_memcpy'
   578 |         __underlying_##op(p, q, __fortify_size);                        \
       |         ^~~~~~~~~~~~~
/kisskb/src/include/linux/fortify-string.h:623:26: note: in expansion of macro '__fortify_memcpy_chk'
   623 | #define memcpy(p, q, s)  __fortify_memcpy_chk(p, q, s,                  \
       |                          ^~~~~~~~~~~~~~~~~~~~
/kisskb/src/arch/s390/kernel/setup.c:526:9: note: in expansion of macro 'memcpy'
   526 |         memcpy(abs_lc->cregs_save_area, S390_lowcore.cregs_save_area,
       |         ^~~~~~

Looks like this was "'__builtin_memcpy' offset [0, 127] is out of the bounds
[0, 0]" before.

Gr{oetje,eeting}s,

 						Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
 							    -- Linus Torvalds