public inbox for libc-alpha@sourceware.org
 help / color / mirror / Atom feed
* [PATCH] x86: Fix bug about glibc.cpu.hwcaps.
@ 2023-03-02  2:33 caiyinyu
  2023-03-02  4:22 ` H.J. Lu
  0 siblings, 1 reply; 16+ messages in thread
From: caiyinyu @ 2023-03-02  2:33 UTC (permalink / raw)
  To: libc-alpha; +Cc: goldstein.w.n, caiyinyu

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


^ permalink raw reply	[flat|nested] 16+ messages in thread
* [PATCH] x86: Fix bug about glibc.cpu.hwcaps.
@ 2023-03-01  3:22 caiyinyu
  2023-03-01  4:19 ` Noah Goldstein
  0 siblings, 1 reply; 16+ messages in thread
From: caiyinyu @ 2023-03-01  3:22 UTC (permalink / raw)
  To: libc-alpha; +Cc: adhemerval.zanella, hjl.tools, carlos, caiyinyu

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


^ permalink raw reply	[flat|nested] 16+ messages in thread

end of thread, other threads:[~2023-03-09  3:25 UTC | newest]

Thread overview: 16+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2023-03-02  2:33 [PATCH] x86: Fix bug about glibc.cpu.hwcaps caiyinyu
2023-03-02  4:22 ` H.J. Lu
2023-03-07 12:45   ` caiyinyu
2023-03-07 13:02     ` Xi Ruoyao
2023-03-07 13:18       ` caiyinyu
2023-03-07 17:23         ` Noah Goldstein
2023-03-08  7:16           ` caiyinyu
2023-03-08 16:56             ` Noah Goldstein
2023-03-09  1:26               ` caiyinyu
2023-03-09  3:25                 ` Xi Ruoyao
  -- strict thread matches above, loose matches on Subject: below --
2023-03-01  3:22 caiyinyu
2023-03-01  4:19 ` Noah Goldstein
2023-03-01  9:10   ` caiyinyu
2023-03-01 16:42     ` Noah Goldstein
2023-03-01 17:33       ` H.J. Lu
2023-03-02  2:37       ` caiyinyu

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).