Re: [Backport PATCH 2/2] x86: Test wcscmp RTM in the wcsncmp overflow case [BZ #28896]

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

On Fri, Feb 18, 2022 at 4:56 PM H.J. Lu <hjl.tools@gmail.com> wrote:
>
> In the overflow fallback strncmp-avx2-rtm and wcsncmp-avx2-rtm would
> call strcmp-avx2 and wcscmp-avx2 respectively. This would have
> not checks around vzeroupper and would trigger spurious
> aborts. This commit fixes that.
>
> test-strcmp, test-strncmp, test-wcscmp, and test-wcsncmp all pass on
> AVX2 machines with and without RTM.
> Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
>
> (cherry picked from commit 7835d611af0854e69a0c71e3806f8fe379282d6f)
> ---
>  sysdeps/x86/Makefile          |  5 ++++-
>  sysdeps/x86/tst-strncmp-rtm.c | 32 +++++++++++++++++++++++---------
>  sysdeps/x86/tst-wcsncmp-rtm.c | 21 +++++++++++++++++++++
>  3 files changed, 48 insertions(+), 10 deletions(-)
>  create mode 100644 sysdeps/x86/tst-wcsncmp-rtm.c
>
> diff --git a/sysdeps/x86/Makefile b/sysdeps/x86/Makefile
> index d110f7b7f2..c6bee981f8 100644
> --- a/sysdeps/x86/Makefile
> +++ b/sysdeps/x86/Makefile
> @@ -99,7 +99,9 @@ tests += \
>    tst-strcpy-rtm \
>    tst-strlen-rtm \
>    tst-strncmp-rtm \
> -  tst-strrchr-rtm
> +  tst-strrchr-rtm \
> +  tst-wcsncmp-rtm \
> +# tests
>
>  CFLAGS-tst-memchr-rtm.c += -mrtm
>  CFLAGS-tst-memcmp-rtm.c += -mrtm
> @@ -111,6 +113,7 @@ CFLAGS-tst-strcpy-rtm.c += -mrtm
>  CFLAGS-tst-strlen-rtm.c += -mrtm
>  CFLAGS-tst-strncmp-rtm.c += -mrtm -Wno-error
>  CFLAGS-tst-strrchr-rtm.c += -mrtm
> +CFLAGS-tst-wcsncmp-rtm.c += -mrtm -Wno-error
>  endif
>
>  ifneq ($(enable-cet),no)
> diff --git a/sysdeps/x86/tst-strncmp-rtm.c b/sysdeps/x86/tst-strncmp-rtm.c
> index 9e20abaacc..b50c11e8d4 100644
> --- a/sysdeps/x86/tst-strncmp-rtm.c
> +++ b/sysdeps/x86/tst-strncmp-rtm.c
> @@ -19,18 +19,32 @@
>  #include <stdint.h>
>  #include <tst-string-rtm.h>
>
> +#ifdef WIDE
> +# define CHAR wchar_t
> +# define MEMSET wmemset
> +# define STRNCMP wcsncmp
> +# define TEST_NAME wcsncmp

This is not a string
> +#else /* !WIDE */
> +# define CHAR char
> +# define MEMSET memset
> +# define STRNCMP strncmp
> +# define TEST_NAME strncmp

This is not a string

Please apply:
https://patchwork.sourceware.org/project/glibc/patch/20220218230025.3505625-1-goldstein.w.n@gmail.com/
> +#endif /* !WIDE */
> +
> +
> +
>  #define LOOP 3000
>  #define STRING_SIZE 1024
> -char string1[STRING_SIZE];
> -char string2[STRING_SIZE];
> +CHAR string1[STRING_SIZE];
> +CHAR string2[STRING_SIZE];
>
>  __attribute__ ((noinline, noclone))
>  static int
>  prepare (void)
>  {
> -  memset (string1, 'a', STRING_SIZE - 1);
> -  memset (string2, 'a', STRING_SIZE - 1);
> -  if (strncmp (string1, string2, STRING_SIZE) == 0)
> +  MEMSET (string1, 'a', STRING_SIZE - 1);
> +  MEMSET (string2, 'a', STRING_SIZE - 1);
> +  if (STRNCMP (string1, string2, STRING_SIZE) == 0)
>      return EXIT_SUCCESS;
>    else
>      return EXIT_FAILURE;
> @@ -40,7 +54,7 @@ __attribute__ ((noinline, noclone))
>  static int
>  function (void)
>  {
> -  if (strncmp (string1, string2, STRING_SIZE) == 0)
> +  if (STRNCMP (string1, string2, STRING_SIZE) == 0)
>      return 0;
>    else
>      return 1;
> @@ -50,7 +64,7 @@ __attribute__ ((noinline, noclone))
>  static int
>  function_overflow (void)
>  {
> -  if (strncmp (string1, string2, SIZE_MAX) == 0)
> +  if (STRNCMP (string1, string2, SIZE_MAX) == 0)
>      return 0;
>    else
>      return 1;
> @@ -59,9 +73,9 @@ function_overflow (void)
>  static int
>  do_test (void)
>  {
> -  int status = do_test_1 ("strncmp", LOOP, prepare, function);
> +  int status = do_test_1 (TEST_NAME, LOOP, prepare, function);
>    if (status != EXIT_SUCCESS)
>      return status;
> -  status = do_test_1 ("strncmp", LOOP, prepare, function_overflow);
> +  status = do_test_1 (TEST_NAME, LOOP, prepare, function_overflow);
>    return status;
>  }
> diff --git a/sysdeps/x86/tst-wcsncmp-rtm.c b/sysdeps/x86/tst-wcsncmp-rtm.c
> new file mode 100644
> index 0000000000..bad3b86378
> --- /dev/null
> +++ b/sysdeps/x86/tst-wcsncmp-rtm.c
> @@ -0,0 +1,21 @@
> +/* Test case for wcsncmp inside a transactionally executing RTM region.
> +   Copyright (C) 2022 Free Software Foundation, Inc.
> +   This file is part of the GNU C Library.
> +
> +   The GNU C Library is free software; you can redistribute it and/or
> +   modify it under the terms of the GNU Lesser General Public
> +   License as published by the Free Software Foundation; either
> +   version 2.1 of the License, or (at your option) any later version.
> +
> +   The GNU C Library is distributed in the hope that it will be useful,
> +   but WITHOUT ANY WARRANTY; without even the implied warranty of
> +   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> +   Lesser General Public License for more details.
> +
> +   You should have received a copy of the GNU Lesser General Public
> +   License along with the GNU C Library; if not, see
> +   <https://www.gnu.org/licenses/>.  */
> +
> +#define WIDE 1
> +#include <wchar.h>
> +#include "tst-strncmp-rtm.c"
> --
> 2.35.1
>