[PATCH v4 2/5] string: Improve coverage in test-strcmp.c and test-strncmp.c

[Noah Goldstein]

On Mon, Feb 7, 2022 at 1:03 PM Noah Goldstein <goldstein.w.n@gmail.com> wrote:
>
> On Mon, Feb 7, 2022 at 8:08 AM Matheus Castanho <msc@linux.ibm.com> wrote:
> >
> >
> > Hi Noah,
> >
> > Noah Goldstein via Libc-alpha <libc-alpha@sourceware.org> writes:
> >
> > > Add additional test cases for small / medium sizes.
> > >
> > > Add tests in test-strncmp.c where `n` is near ULONG_MAX or LONG_MIN to
> > > test for overflow bugs in length handling.
> > >
> > > Signed-off-by: Noah Goldstein <goldstein.w.n@gmail.com>
> > > ---
> > >  string/test-strcmp.c  |  70 ++++++++++--
> > >  string/test-strncmp.c | 257 +++++++++++++++++++++++++++++++++++++++---
> > >  2 files changed, 306 insertions(+), 21 deletions(-)
> > >
> > > diff --git a/string/test-strcmp.c b/string/test-strcmp.c
> > > index 97d7bf5043..eacbdc8857 100644
> > > --- a/string/test-strcmp.c
> > > +++ b/string/test-strcmp.c
> > > @@ -16,6 +16,9 @@
> > >     License along with the GNU C Library; if not, see
> > >     <https://www.gnu.org/licenses/>.  */
> > >
> > > +#define TEST_LEN (4096 * 3)
> > > +#define MIN_PAGE_SIZE (TEST_LEN + 2 * getpagesize ())
> >
> > Is this change really necessary? It broke the tests on ppc64le because
> > the default page size is 64kB, which this new value is not a multiple
> > of, causing mprotect to fail with EINVAL in test_init.

Posted a patch I think fixes the issue at.
```
String: Ensure 'MIN_PAGE_SIZE' is factor of 'getpagesize'
```
>
> We can make MIN_PAGE_SIZE (8 * getpagesize ())?
> >
> > --
> > Matheus Castanho