From: "H.J. Lu" <hjl.tools@gmail.com>
To: Stable GNU C Library <libc-stable@sourceware.org>
Subject: [Backport PATCH 1/2] x86: Fallback {str|wcs}cmp RTM in the ncmp overflow case [BZ #28896]
Date: Fri, 18 Feb 2022 14:55:24 -0800 [thread overview]
Message-ID: <YhAj3J0SlF2DJHkv@gmail.com> (raw)
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.
Co-authored-by: H.J. Lu <hjl.tools@gmail.com>
(cherry picked from commit c6272098323153db373f2986c67786ea8c85f1cf)
---
sysdeps/x86/Makefile | 2 +-
sysdeps/x86/tst-strncmp-rtm.c | 17 ++++++++++++++++-
sysdeps/x86_64/multiarch/strcmp-avx2.S | 2 +-
sysdeps/x86_64/multiarch/strncmp-avx2-rtm.S | 1 +
sysdeps/x86_64/multiarch/strncmp-avx2.S | 1 +
sysdeps/x86_64/multiarch/wcsncmp-avx2-rtm.S | 2 +-
sysdeps/x86_64/multiarch/wcsncmp-avx2.S | 2 +-
7 files changed, 22 insertions(+), 5 deletions(-)
diff --git a/sysdeps/x86/Makefile b/sysdeps/x86/Makefile
index 6cf708335c..d110f7b7f2 100644
--- a/sysdeps/x86/Makefile
+++ b/sysdeps/x86/Makefile
@@ -109,7 +109,7 @@ CFLAGS-tst-memset-rtm.c += -mrtm
CFLAGS-tst-strchr-rtm.c += -mrtm
CFLAGS-tst-strcpy-rtm.c += -mrtm
CFLAGS-tst-strlen-rtm.c += -mrtm
-CFLAGS-tst-strncmp-rtm.c += -mrtm
+CFLAGS-tst-strncmp-rtm.c += -mrtm -Wno-error
CFLAGS-tst-strrchr-rtm.c += -mrtm
endif
diff --git a/sysdeps/x86/tst-strncmp-rtm.c b/sysdeps/x86/tst-strncmp-rtm.c
index 09ed6fa0d6..9e20abaacc 100644
--- a/sysdeps/x86/tst-strncmp-rtm.c
+++ b/sysdeps/x86/tst-strncmp-rtm.c
@@ -16,6 +16,7 @@
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
+#include <stdint.h>
#include <tst-string-rtm.h>
#define LOOP 3000
@@ -45,8 +46,22 @@ function (void)
return 1;
}
+__attribute__ ((noinline, noclone))
+static int
+function_overflow (void)
+{
+ if (strncmp (string1, string2, SIZE_MAX) == 0)
+ return 0;
+ else
+ return 1;
+}
+
static int
do_test (void)
{
- return do_test_1 ("strncmp", LOOP, prepare, function);
+ int status = do_test_1 ("strncmp", LOOP, prepare, function);
+ if (status != EXIT_SUCCESS)
+ return status;
+ status = do_test_1 ("strncmp", LOOP, prepare, function_overflow);
+ return status;
}
diff --git a/sysdeps/x86_64/multiarch/strcmp-avx2.S b/sysdeps/x86_64/multiarch/strcmp-avx2.S
index 9c73b5899d..cdcb3c5a26 100644
--- a/sysdeps/x86_64/multiarch/strcmp-avx2.S
+++ b/sysdeps/x86_64/multiarch/strcmp-avx2.S
@@ -95,7 +95,7 @@ ENTRY (STRCMP)
length to bound a valid memory region. In these cases just use
'wcscmp'. */
shrq $56, %rcx
- jnz __wcscmp_avx2
+ jnz OVERFLOW_STRCMP
# endif
/* Convert units: from wide to byte char. */
shl $2, %RDX_LP
diff --git a/sysdeps/x86_64/multiarch/strncmp-avx2-rtm.S b/sysdeps/x86_64/multiarch/strncmp-avx2-rtm.S
index 37d1224bb9..68bad365ba 100644
--- a/sysdeps/x86_64/multiarch/strncmp-avx2-rtm.S
+++ b/sysdeps/x86_64/multiarch/strncmp-avx2-rtm.S
@@ -1,3 +1,4 @@
#define STRCMP __strncmp_avx2_rtm
#define USE_AS_STRNCMP 1
+#define OVERFLOW_STRCMP __strcmp_avx2_rtm
#include "strcmp-avx2-rtm.S"
diff --git a/sysdeps/x86_64/multiarch/strncmp-avx2.S b/sysdeps/x86_64/multiarch/strncmp-avx2.S
index 1678bcc235..f138e9f1fd 100644
--- a/sysdeps/x86_64/multiarch/strncmp-avx2.S
+++ b/sysdeps/x86_64/multiarch/strncmp-avx2.S
@@ -1,3 +1,4 @@
#define STRCMP __strncmp_avx2
#define USE_AS_STRNCMP 1
+#define OVERFLOW_STRCMP __strcmp_avx2
#include "strcmp-avx2.S"
diff --git a/sysdeps/x86_64/multiarch/wcsncmp-avx2-rtm.S b/sysdeps/x86_64/multiarch/wcsncmp-avx2-rtm.S
index 4e88c70cc6..f467582cbe 100644
--- a/sysdeps/x86_64/multiarch/wcsncmp-avx2-rtm.S
+++ b/sysdeps/x86_64/multiarch/wcsncmp-avx2-rtm.S
@@ -1,5 +1,5 @@
#define STRCMP __wcsncmp_avx2_rtm
#define USE_AS_STRNCMP 1
#define USE_AS_WCSCMP 1
-
+#define OVERFLOW_STRCMP __wcscmp_avx2_rtm
#include "strcmp-avx2-rtm.S"
diff --git a/sysdeps/x86_64/multiarch/wcsncmp-avx2.S b/sysdeps/x86_64/multiarch/wcsncmp-avx2.S
index 4fa1de4d3f..e9ede522b8 100644
--- a/sysdeps/x86_64/multiarch/wcsncmp-avx2.S
+++ b/sysdeps/x86_64/multiarch/wcsncmp-avx2.S
@@ -1,5 +1,5 @@
#define STRCMP __wcsncmp_avx2
#define USE_AS_STRNCMP 1
#define USE_AS_WCSCMP 1
-
+#define OVERFLOW_STRCMP __wcscmp_avx2
#include "strcmp-avx2.S"
--
2.35.1
next reply other threads:[~2022-02-18 22:55 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-18 22:55 H.J. Lu [this message]
2022-02-18 22:56 ` Noah Goldstein
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