[PATCH v2] String: Ensure 'MIN_PAGE_SIZE' is multiple of 'getpagesize'

[Noah Goldstein]

On Tue, Feb 8, 2022 at 7:59 AM Matheus Castanho <msc@linux.ibm.com> wrote:
>
>
> string/test-strcmp and wcsmbs/test-wcscmp are passing with this new
> patch, but string/test-strncmp and wcsmbs/test-wcsncmp are failing to
> compile. With the fix below all tests pass.
>
> Tested on powerpc, powerpc64 and powerpc64le.
>
> Noah Goldstein via Libc-alpha <libc-alpha@sourceware.org> writes:
>
> > When 'TEST_LEN' was defined as (4096 * 3) the allocation size Would
> > not be a multiple of system page size if system page size > 4096.
> > ---
> >  string/test-strcmp.c  | 14 +++++++-------
> >  string/test-strncmp.c | 18 +++++++++---------
> >  2 files changed, 16 insertions(+), 16 deletions(-)
> >
> > diff --git a/string/test-strcmp.c b/string/test-strcmp.c
> > index eacbdc8857..0abce769d0 100644
> > --- a/string/test-strcmp.c
> > +++ b/string/test-strcmp.c
> > @@ -16,7 +16,7 @@
> >     License along with the GNU C Library; if not, see
> >     <https://www.gnu.org/licenses/>.  */
> >
> > -#define TEST_LEN (4096 * 3)
> > +#define TEST_LEN (getpagesize () * 3)
> >  #define MIN_PAGE_SIZE (TEST_LEN + 2 * getpagesize ())
> >
> >  #define TEST_MAIN
> > @@ -393,7 +393,7 @@ int
> >  test_main (void)
> >  {
> >    size_t i, j;
> > -
> > +  const size_t test_len = MIN(TEST_LEN, 3 * 4096);
> >    test_init ();
> >    check();
> >    check2 ();
> > @@ -435,7 +435,7 @@ test_main (void)
> >
> >    for (j = 0; j < 160; ++j)
> >      {
> > -      for (i = 0; i < TEST_LEN;)
> > +      for (i = 0; i < test_len;)
> >          {
> >            do_test (getpagesize () - j - 1, 0, i, 127, 0);
> >            do_test (getpagesize () - j - 1, 0, i, 127, 1);
> > @@ -461,17 +461,17 @@ test_main (void)
> >              {
> >                i += 7;
> >              }
> > -          else if (i + 161 < TEST_LEN)
> > +          else if (i + 161 < test_len)
> >              {
> >                i += 31;
> >                i *= 17;
> >                i /= 16;
> > -              if (i + 161 > TEST_LEN)
> > +              if (i + 161 > test_len)
> >                  {
> > -                  i = TEST_LEN - 160;
> > +                  i = test_len - 160;
> >                  }
> >              }
> > -          else if (i + 32 < TEST_LEN)
> > +          else if (i + 32 < test_len)
> >              {
> >                i += 7;
> >              }
> > diff --git a/string/test-strncmp.c b/string/test-strncmp.c
> > index 1a3cee1792..1966bde3fe 100644
> > --- a/string/test-strncmp.c
> > +++ b/string/test-strncmp.c
> > @@ -16,7 +16,7 @@
> >     License along with the GNU C Library; if not, see
> >     <https://www.gnu.org/licenses/>.  */
> >
> > -#define TEST_LEN (4096 * 3)
> > +#define TEST_LEN (getpagesize () * 3)
> >  #define MIN_PAGE_SIZE (TEST_LEN + 2 * getpagesize ())
> >
> >  #define TEST_MAIN
> > @@ -430,7 +430,7 @@ check_overflow (void)
> >    const size_t of_masks[]
> >        = { ULONG_MAX, LONG_MIN, ULONG_MAX - (ULONG_MAX >> 2),
> >            ((size_t)LONG_MAX) >> 1 };
> > -
> > +  const size_t test_len = MIN(test_len, 3 * 4096);
>
> Should be MIN(TEST_LEN, 3 * 4096)
>
> >    for (of_idx = 0; of_idx < sizeof (of_masks) / sizeof (of_masks[0]); ++of_idx)
> >      {
> >        of_mask = of_masks[of_idx];
> > @@ -484,7 +484,7 @@ check_overflow (void)
> >                           of_mask - j * 2, 0, 127, -1);
> >              }
> >
> > -          for (i = 1; i < TEST_LEN; i += i)
> > +          for (i = 1; i < test_len; i += i)
> >              {
> >                do_test_n (j, 0, i - 1, of_mask, 0, 127, 0);
> >                do_test_n (j, 0, i - 1, of_mask, 0, 127, 1);
> > @@ -540,7 +540,7 @@ int
> >  test_main (void)
> >  {
> >    size_t i, j;
> > -
> > +  const size_t test_len = MIN(test_len, 3 * 4096);
>
> Should be MIN(TEST_LEN, 3 * 4096)

Fixed in V3. Sorry about that.
>
> >    test_init ();
> >
> >    check1 ();
> > @@ -608,7 +608,7 @@ test_main (void)
> >
> >    for (j = 0; j < 160; ++j)
> >      {
> > -      for (i = 0; i < TEST_LEN;)
> > +      for (i = 0; i < test_len;)
> >          {
> >            do_test_n (getpagesize () - j - 1, 0, i, i + 1, 0, 127, 0);
> >            do_test_n (getpagesize () - j - 1, 0, i, i + 1, 0, 127, 1);
> > @@ -677,17 +677,17 @@ test_main (void)
> >              {
> >                i += 7;
> >              }
> > -          else if (i + 161 < TEST_LEN)
> > +          else if (i + 161 < test_len)
> >              {
> >                i += 31;
> >                i *= 17;
> >                i /= 16;
> > -              if (i + 161 > TEST_LEN)
> > +              if (i + 161 > test_len)
> >                  {
> > -                  i = TEST_LEN - 160;
> > +                  i = test_len - 160;
> >                  }
> >              }
> > -          else if (i + 32 < TEST_LEN)
> > +          else if (i + 32 < test_len)
> >              {
> >                i += 7;
> >              }
>
>
> --
> Matheus Castanho