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

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

On Wed, Mar 8, 2023 at 1:16 AM caiyinyu <caiyinyu@loongson.cn> wrote:
>
>
> 在 2023/3/8 上午1:23, Noah Goldstein 写道:
> > On Tue, Mar 7, 2023 at 7:18 AM caiyinyu <caiyinyu@loongson.cn> wrote:
> >>
> >> 在 2023/3/7 下午9:02, Xi Ruoyao 写道:
> >>> On Tue, 2023-03-07 at 20:45 +0800, caiyinyu wrote:
> >>>> 在 2023/3/2 下午12:22, H.J. Lu 写道:
> >>>>> On Wed, Mar 1, 2023 at 6:36 PM caiyinyu <caiyinyu@loongson.cn>
> >>>>> wrote:
> >>>>>> Recorded in [BZ #30183]:
> >>>>>>
> >>>>>> 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
> >>>>>>
> >>>>> OK.
> >>>>>
> >>>>> Thanks.
> >>>> Could you help to push this patch?
> >>> I guess you can push it yourself.  A port maintainer has write access to
> >>> the entire Git repository, just use it carefully (i. e. always get a
> >>> permission before changing other subsystems).
> >>>
> >> OK, thanks.
> > did you add the tests HJ asked for?
>
> Not yet.
It also doesn't have the BZ number in the commit message. In the future please
wait for approval before pushing.

>
>