Re: Build regressions/improvements in v6.2-rc4

Geert Uytterhoeven
2023-01-16T12:36:42Z

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