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x86: Fix fallback for wcsncmp_avx2 in strcmp-avx2.S [BZ #28896]

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Overflow case for __wcsncmp_avx2_rtm should be __wcscmp_avx2_rtm not
__wcscmp_avx2.

commit ddf0992cf5
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.
Reviewed-by: H.J. Lu <hjl.tools@gmail.com>

(cherry picked from commit 9fef7039a7)
This commit is contained in:
Noah Goldstein 2022-03-24 15:50:33 -05:00 committed by Sunil K Pandey
parent 676f7bcf11
commit 059e36d9ed
2 changed files with 16 additions and 1 deletions
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15
sysdeps/x86/tst-strncmp-rtm.c
View File

@ -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;
}

2
sysdeps/x86_64/multiarch/strcmp-avx2.S
View File

@ -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