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

[Geert Uytterhoeven]

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@xxxxxxxxxxxxxx

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