diff mbox series

[v2,12/31] x86: Fix fallback for wcsncmp_avx2 in strcmp-avx2.S [BZ #28896]

Message ID 20220324205033.3274646-1-goldstein.w.n@gmail.com
State Accepted, archived
Headers
Series None |

Commit Message

Noah Goldstein March 24, 2022, 8:50 p.m. UTC 
  Overflow case for __wcsncmp_avx2_rtm should be __wcscmp_avx2_rtm not
__wcscmp_avx2.

commit ddf0992cf57a93200e0c782e2a94d0733a5a0b87
Author: Noah Goldstein <goldstein.w.n@gmail.com>
Date:   Sun Jan 9 16:02:21 2022 -0600

    x86: Fix __wcsncmp_avx2 in strcmp-avx2.S [BZ# 28755]

Set the wrong fallback function for `__wcsncmp_avx2_rtm`. It was set
to fallback on to `__wcscmp_avx2` instead of `__wcscmp_avx2_rtm` which
can cause spurious aborts.

This change will need to be backported.

All string/memory tests pass.
---
 sysdeps/x86/tst-strncmp-rtm.c          | 15 +++++++++++++++
 sysdeps/x86_64/multiarch/strcmp-avx2.S |  2 +-
 2 files changed, 16 insertions(+), 1 deletion(-)

Comments

H.J. Lu March 24, 2022, 9:26 p.m. UTC | #1 
On Thu, Mar 24, 2022 at 1:50 PM Noah Goldstein <goldstein.w.n@gmail.com> wrote:
>
> Overflow case for __wcsncmp_avx2_rtm should be __wcscmp_avx2_rtm not
> __wcscmp_avx2.
>
> commit ddf0992cf57a93200e0c782e2a94d0733a5a0b87
> Author: Noah Goldstein <goldstein.w.n@gmail.com>
> Date:   Sun Jan 9 16:02:21 2022 -0600
>
>     x86: Fix __wcsncmp_avx2 in strcmp-avx2.S [BZ# 28755]
>
> Set the wrong fallback function for `__wcsncmp_avx2_rtm`. It was set
> to fallback on to `__wcscmp_avx2` instead of `__wcscmp_avx2_rtm` which
> can cause spurious aborts.
>
> This change will need to be backported.
>
> All string/memory tests pass.
> ---
>  sysdeps/x86/tst-strncmp-rtm.c          | 15 +++++++++++++++
>  sysdeps/x86_64/multiarch/strcmp-avx2.S |  2 +-
>  2 files changed, 16 insertions(+), 1 deletion(-)
>
> diff --git a/sysdeps/x86/tst-strncmp-rtm.c b/sysdeps/x86/tst-strncmp-rtm.c
> index 300bc8c281..a3b14e72ff 100644
> --- a/sysdeps/x86/tst-strncmp-rtm.c
> +++ b/sysdeps/x86/tst-strncmp-rtm.c
> @@ -70,6 +70,16 @@ function_overflow (void)
>      return 1;
>  }
>
> +__attribute__ ((noinline, noclone))
> +static int
> +function_overflow2 (void)
> +{
> +  if (STRNCMP (string1, string2, SIZE_MAX >> 4) == 0)
> +    return 0;
> +  else
> +    return 1;
> +}
> +
>  static int
>  do_test (void)
>  {
> @@ -77,5 +87,10 @@ do_test (void)
>    if (status != EXIT_SUCCESS)
>      return status;
>    status = do_test_1 (TEST_NAME, LOOP, prepare, function_overflow);
> +  if (status != EXIT_SUCCESS)
> +    return status;
> +  status = do_test_1 (TEST_NAME, LOOP, prepare, function_overflow2);
> +  if (status != EXIT_SUCCESS)
> +    return status;
>    return status;
>  }
> diff --git a/sysdeps/x86_64/multiarch/strcmp-avx2.S b/sysdeps/x86_64/multiarch/strcmp-avx2.S
> index 52ff5ad724..86a86b68e3 100644
> --- a/sysdeps/x86_64/multiarch/strcmp-avx2.S
> +++ b/sysdeps/x86_64/multiarch/strcmp-avx2.S
> @@ -122,7 +122,7 @@ ENTRY(STRCMP)
>            are cases where length is large enough that it can never be a
>            bound on valid memory so just use wcscmp.  */
>         shrq    $56, %rcx
> -       jnz     __wcscmp_avx2
> +       jnz     OVERFLOW_STRCMP
>
>         leaq    (, %rdx, 4), %rdx
>  #  endif
> --
> 2.25.1
>

LGTM.   Verified on AVX2 machine with RTM.  Without the fix,
the new testcase failed.

Reviewed-by: H.J. Lu <hjl.tools@gmail.com>

Thanks.
Noah Goldstein March 24, 2022, 9:43 p.m. UTC | #2 
On Thu, Mar 24, 2022 at 4:26 PM H.J. Lu <hjl.tools@gmail.com> wrote:
>
> On Thu, Mar 24, 2022 at 1:50 PM Noah Goldstein <goldstein.w.n@gmail.com> wrote:
> >
> > Overflow case for __wcsncmp_avx2_rtm should be __wcscmp_avx2_rtm not
> > __wcscmp_avx2.
> >
> > commit ddf0992cf57a93200e0c782e2a94d0733a5a0b87
> > Author: Noah Goldstein <goldstein.w.n@gmail.com>
> > Date:   Sun Jan 9 16:02:21 2022 -0600
> >
> >     x86: Fix __wcsncmp_avx2 in strcmp-avx2.S [BZ# 28755]
> >
> > Set the wrong fallback function for `__wcsncmp_avx2_rtm`. It was set
> > to fallback on to `__wcscmp_avx2` instead of `__wcscmp_avx2_rtm` which
> > can cause spurious aborts.
> >
> > This change will need to be backported.
> >
> > All string/memory tests pass.
> > ---
> >  sysdeps/x86/tst-strncmp-rtm.c          | 15 +++++++++++++++
> >  sysdeps/x86_64/multiarch/strcmp-avx2.S |  2 +-
> >  2 files changed, 16 insertions(+), 1 deletion(-)
> >
> > diff --git a/sysdeps/x86/tst-strncmp-rtm.c b/sysdeps/x86/tst-strncmp-rtm.c
> > index 300bc8c281..a3b14e72ff 100644
> > --- a/sysdeps/x86/tst-strncmp-rtm.c
> > +++ b/sysdeps/x86/tst-strncmp-rtm.c
> > @@ -70,6 +70,16 @@ function_overflow (void)
> >      return 1;
> >  }
> >
> > +__attribute__ ((noinline, noclone))
> > +static int
> > +function_overflow2 (void)
> > +{
> > +  if (STRNCMP (string1, string2, SIZE_MAX >> 4) == 0)
> > +    return 0;
> > +  else
> > +    return 1;
> > +}
> > +
> >  static int
> >  do_test (void)
> >  {
> > @@ -77,5 +87,10 @@ do_test (void)
> >    if (status != EXIT_SUCCESS)
> >      return status;
> >    status = do_test_1 (TEST_NAME, LOOP, prepare, function_overflow);
> > +  if (status != EXIT_SUCCESS)
> > +    return status;
> > +  status = do_test_1 (TEST_NAME, LOOP, prepare, function_overflow2);
> > +  if (status != EXIT_SUCCESS)
> > +    return status;
> >    return status;
> >  }
> > diff --git a/sysdeps/x86_64/multiarch/strcmp-avx2.S b/sysdeps/x86_64/multiarch/strcmp-avx2.S
> > index 52ff5ad724..86a86b68e3 100644
> > --- a/sysdeps/x86_64/multiarch/strcmp-avx2.S
> > +++ b/sysdeps/x86_64/multiarch/strcmp-avx2.S
> > @@ -122,7 +122,7 @@ ENTRY(STRCMP)
> >            are cases where length is large enough that it can never be a
> >            bound on valid memory so just use wcscmp.  */
> >         shrq    $56, %rcx
> > -       jnz     __wcscmp_avx2
> > +       jnz     OVERFLOW_STRCMP
> >
> >         leaq    (, %rdx, 4), %rdx
> >  #  endif
> > --
> > 2.25.1
> >
>
> LGTM.   Verified on AVX2 machine with RTM.  Without the fix,
> the new testcase failed.

And that w/ the fix it passes?
>
> Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
>
> Thanks.
>
> --
> H.J.
H.J. Lu March 24, 2022, 9:58 p.m. UTC | #3 
On Thu, Mar 24, 2022 at 2:43 PM Noah Goldstein <goldstein.w.n@gmail.com> wrote:
>
> On Thu, Mar 24, 2022 at 4:26 PM H.J. Lu <hjl.tools@gmail.com> wrote:
> >
> > On Thu, Mar 24, 2022 at 1:50 PM Noah Goldstein <goldstein.w.n@gmail.com> wrote:
> > >
> > > Overflow case for __wcsncmp_avx2_rtm should be __wcscmp_avx2_rtm not
> > > __wcscmp_avx2.
> > >
> > > commit ddf0992cf57a93200e0c782e2a94d0733a5a0b87
> > > Author: Noah Goldstein <goldstein.w.n@gmail.com>
> > > Date:   Sun Jan 9 16:02:21 2022 -0600
> > >
> > >     x86: Fix __wcsncmp_avx2 in strcmp-avx2.S [BZ# 28755]
> > >
> > > Set the wrong fallback function for `__wcsncmp_avx2_rtm`. It was set
> > > to fallback on to `__wcscmp_avx2` instead of `__wcscmp_avx2_rtm` which
> > > can cause spurious aborts.
> > >
> > > This change will need to be backported.
> > >
> > > All string/memory tests pass.
> > > ---
> > >  sysdeps/x86/tst-strncmp-rtm.c          | 15 +++++++++++++++
> > >  sysdeps/x86_64/multiarch/strcmp-avx2.S |  2 +-
> > >  2 files changed, 16 insertions(+), 1 deletion(-)
> > >
> > > diff --git a/sysdeps/x86/tst-strncmp-rtm.c b/sysdeps/x86/tst-strncmp-rtm.c
> > > index 300bc8c281..a3b14e72ff 100644
> > > --- a/sysdeps/x86/tst-strncmp-rtm.c
> > > +++ b/sysdeps/x86/tst-strncmp-rtm.c
> > > @@ -70,6 +70,16 @@ function_overflow (void)
> > >      return 1;
> > >  }
> > >
> > > +__attribute__ ((noinline, noclone))
> > > +static int
> > > +function_overflow2 (void)
> > > +{
> > > +  if (STRNCMP (string1, string2, SIZE_MAX >> 4) == 0)
> > > +    return 0;
> > > +  else
> > > +    return 1;
> > > +}
> > > +
> > >  static int
> > >  do_test (void)
> > >  {
> > > @@ -77,5 +87,10 @@ do_test (void)
> > >    if (status != EXIT_SUCCESS)
> > >      return status;
> > >    status = do_test_1 (TEST_NAME, LOOP, prepare, function_overflow);
> > > +  if (status != EXIT_SUCCESS)
> > > +    return status;
> > > +  status = do_test_1 (TEST_NAME, LOOP, prepare, function_overflow2);
> > > +  if (status != EXIT_SUCCESS)
> > > +    return status;
> > >    return status;
> > >  }
> > > diff --git a/sysdeps/x86_64/multiarch/strcmp-avx2.S b/sysdeps/x86_64/multiarch/strcmp-avx2.S
> > > index 52ff5ad724..86a86b68e3 100644
> > > --- a/sysdeps/x86_64/multiarch/strcmp-avx2.S
> > > +++ b/sysdeps/x86_64/multiarch/strcmp-avx2.S
> > > @@ -122,7 +122,7 @@ ENTRY(STRCMP)
> > >            are cases where length is large enough that it can never be a
> > >            bound on valid memory so just use wcscmp.  */
> > >         shrq    $56, %rcx
> > > -       jnz     __wcscmp_avx2
> > > +       jnz     OVERFLOW_STRCMP
> > >
> > >         leaq    (, %rdx, 4), %rdx
> > >  #  endif
> > > --
> > > 2.25.1
> > >
> >
> > LGTM.   Verified on AVX2 machine with RTM.  Without the fix,
> > the new testcase failed.
>
> And that w/ the fix it passes?

Yes.

> >
> > Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
> >
> > Thanks.
> >
> > --
> > H.J.
Sunil Pandey May 4, 2022, 6:05 a.m. UTC | #4 
On Thu, Mar 24, 2022 at 2:59 PM H.J. Lu via Libc-alpha
<libc-alpha@sourceware.org> wrote:
>
> On Thu, Mar 24, 2022 at 2:43 PM Noah Goldstein <goldstein.w.n@gmail.com> wrote:
> >
> > On Thu, Mar 24, 2022 at 4:26 PM H.J. Lu <hjl.tools@gmail.com> wrote:
> > >
> > > On Thu, Mar 24, 2022 at 1:50 PM Noah Goldstein <goldstein.w.n@gmail.com> wrote:
> > > >
> > > > Overflow case for __wcsncmp_avx2_rtm should be __wcscmp_avx2_rtm not
> > > > __wcscmp_avx2.
> > > >
> > > > commit ddf0992cf57a93200e0c782e2a94d0733a5a0b87
> > > > Author: Noah Goldstein <goldstein.w.n@gmail.com>
> > > > Date:   Sun Jan 9 16:02:21 2022 -0600
> > > >
> > > >     x86: Fix __wcsncmp_avx2 in strcmp-avx2.S [BZ# 28755]
> > > >
> > > > Set the wrong fallback function for `__wcsncmp_avx2_rtm`. It was set
> > > > to fallback on to `__wcscmp_avx2` instead of `__wcscmp_avx2_rtm` which
> > > > can cause spurious aborts.
> > > >
> > > > This change will need to be backported.
> > > >
> > > > All string/memory tests pass.
> > > > ---
> > > >  sysdeps/x86/tst-strncmp-rtm.c          | 15 +++++++++++++++
> > > >  sysdeps/x86_64/multiarch/strcmp-avx2.S |  2 +-
> > > >  2 files changed, 16 insertions(+), 1 deletion(-)
> > > >
> > > > diff --git a/sysdeps/x86/tst-strncmp-rtm.c b/sysdeps/x86/tst-strncmp-rtm.c
> > > > index 300bc8c281..a3b14e72ff 100644
> > > > --- a/sysdeps/x86/tst-strncmp-rtm.c
> > > > +++ b/sysdeps/x86/tst-strncmp-rtm.c
> > > > @@ -70,6 +70,16 @@ function_overflow (void)
> > > >      return 1;
> > > >  }
> > > >
> > > > +__attribute__ ((noinline, noclone))
> > > > +static int
> > > > +function_overflow2 (void)
> > > > +{
> > > > +  if (STRNCMP (string1, string2, SIZE_MAX >> 4) == 0)
> > > > +    return 0;
> > > > +  else
> > > > +    return 1;
> > > > +}
> > > > +
> > > >  static int
> > > >  do_test (void)
> > > >  {
> > > > @@ -77,5 +87,10 @@ do_test (void)
> > > >    if (status != EXIT_SUCCESS)
> > > >      return status;
> > > >    status = do_test_1 (TEST_NAME, LOOP, prepare, function_overflow);
> > > > +  if (status != EXIT_SUCCESS)
> > > > +    return status;
> > > > +  status = do_test_1 (TEST_NAME, LOOP, prepare, function_overflow2);
> > > > +  if (status != EXIT_SUCCESS)
> > > > +    return status;
> > > >    return status;
> > > >  }
> > > > diff --git a/sysdeps/x86_64/multiarch/strcmp-avx2.S b/sysdeps/x86_64/multiarch/strcmp-avx2.S
> > > > index 52ff5ad724..86a86b68e3 100644
> > > > --- a/sysdeps/x86_64/multiarch/strcmp-avx2.S
> > > > +++ b/sysdeps/x86_64/multiarch/strcmp-avx2.S
> > > > @@ -122,7 +122,7 @@ ENTRY(STRCMP)
> > > >            are cases where length is large enough that it can never be a
> > > >            bound on valid memory so just use wcscmp.  */
> > > >         shrq    $56, %rcx
> > > > -       jnz     __wcscmp_avx2
> > > > +       jnz     OVERFLOW_STRCMP
> > > >
> > > >         leaq    (, %rdx, 4), %rdx
> > > >  #  endif
> > > > --
> > > > 2.25.1
> > > >
> > >
> > > LGTM.   Verified on AVX2 machine with RTM.  Without the fix,
> > > the new testcase failed.
> >
> > And that w/ the fix it passes?
>
> Yes.
>
> > >
> > > Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
> > >
> > > Thanks.
> > >
> > > --
> > > H.J.
>
>
>
> --
> H.J.

I would like to backport this patch to release branches.
Any comments or objections?

--Sunil
diff mbox series

Patch

diff --git a/sysdeps/x86/tst-strncmp-rtm.c b/sysdeps/x86/tst-strncmp-rtm.c
index 300bc8c281..a3b14e72ff 100644
--- a/sysdeps/x86/tst-strncmp-rtm.c
+++ b/sysdeps/x86/tst-strncmp-rtm.c
@@ -70,6 +70,16 @@  function_overflow (void)
     return 1;
 }
 
+__attribute__ ((noinline, noclone))
+static int
+function_overflow2 (void)
+{
+  if (STRNCMP (string1, string2, SIZE_MAX >> 4) == 0)
+    return 0;
+  else
+    return 1;
+}
+
 static int
 do_test (void)
 {
@@ -77,5 +87,10 @@  do_test (void)
   if (status != EXIT_SUCCESS)
     return status;
   status = do_test_1 (TEST_NAME, LOOP, prepare, function_overflow);
+  if (status != EXIT_SUCCESS)
+    return status;
+  status = do_test_1 (TEST_NAME, LOOP, prepare, function_overflow2);
+  if (status != EXIT_SUCCESS)
+    return status;
   return status;
 }
diff --git a/sysdeps/x86_64/multiarch/strcmp-avx2.S b/sysdeps/x86_64/multiarch/strcmp-avx2.S
index 52ff5ad724..86a86b68e3 100644
--- a/sysdeps/x86_64/multiarch/strcmp-avx2.S
+++ b/sysdeps/x86_64/multiarch/strcmp-avx2.S
@@ -122,7 +122,7 @@  ENTRY(STRCMP)
 	   are cases where length is large enough that it can never be a
 	   bound on valid memory so just use wcscmp.  */
 	shrq	$56, %rcx
-	jnz	__wcscmp_avx2
+	jnz	OVERFLOW_STRCMP
 
 	leaq	(, %rdx, 4), %rdx
 #  endif