Re: [PATCH] x86: Fix bug about glibc.cpu.hwcaps.

[Noah Goldstein <goldstein.w.n@gmail.com>]

On Wed, Mar 1, 2023 at 3:11 AM caiyinyu <caiyinyu@loongson.cn> wrote:
>
>
> 在 2023/3/1 下午12:19, Noah Goldstein 写道:
> > On Tue, Feb 28, 2023 at 9:22 PM caiyinyu <caiyinyu@loongson.cn> wrote:
> >> 1. export GLIBC_TUNABLES=glibc.cpu.hwcaps=-AVX512
> >> 2. Add  _dl_printf("p -- %s\n", p); just before switch(nl) in
> >>     sysdeps/x86/cpu-tunables.c
> >> 3. compiled and run ./testrun.sh /usr/bin/ls
> >> you will get:
> >>
> >> p -- -AVX512
> >> p -- LC_ADDRESS=en_US.UTF-8
> >> p -- LC_NUMERIC=C
> >> ...
> >>
> >> The function, TUNABLE_CALLBACK (set_hwcaps)
> >> (tunable_val_t *valp), checks far more than it should and it
> >> should stop at end of "-AVX512".
> >> ---
> >>   sysdeps/x86/cpu-tunables.c | 6 +++---
> >>   1 file changed, 3 insertions(+), 3 deletions(-)
> >>
> >> diff --git a/sysdeps/x86/cpu-tunables.c b/sysdeps/x86/cpu-tunables.c
> >> index d3e1367bda..772fb0c4c2 100644
> >> --- a/sysdeps/x86/cpu-tunables.c
> >> +++ b/sysdeps/x86/cpu-tunables.c
> >> @@ -107,13 +107,13 @@ TUNABLE_CALLBACK (set_hwcaps) (tunable_val_t *valp)
> >>        NOTE: the IFUNC selection may change over time.  Please check all
> >>        multiarch implementations when experimenting.  */
> >>
> >> -  const char *p = valp->strval;
> >> +  const char *p = valp->strval, *c;
> >>     struct cpu_features *cpu_features = &GLRO(dl_x86_cpu_features);
> >>     size_t len;
> >>
> >>     do
> >>       {
> >> -      const char *c, *n;
> >> +      const char *n;
> >>         bool disable;
> >>         size_t nl;
> >>
> >> @@ -283,7 +283,7 @@ TUNABLE_CALLBACK (set_hwcaps) (tunable_val_t *valp)
> >>          }
> >>         p += len + 1;
> >>       }
> >> -  while (*p != '\0');
> >> +  while (*c != '\0');
> >>   }
> >>
> >>   # if CET_ENABLED
> >> --
> >> 2.31.1
> >>
> > Can you make a bugzilla for this?
> bugzilla:
>
> https://sourceware.org/bugzilla/show_bug.cgi?id=30183
>
>
Can you append '[BZ #30183]' to the commit message.
Otherwise looks good.