On Sun, Oct 25, 2020 at 10:48:38PM +0100, Rasmus Villemoes wrote: > This is a bit of a mixed bag. > > The background is that I have some sort() and list_sort() rework > planned, but as part of that series I want to extend their their test > suites somewhat to make sure I don't goof up - and I want to use lots > of random list lengths with random contents to increase the chance of > somebody eventually hitting "hey, sort() is broken when the length is > 3 less than a power of 2 and only the last two elements are out of > order". But when such a case is hit, it's vitally important that the > developer can reproduce the exact same test case, which means using a > deterministic sequence of random numbers. > > Since Petr noticed [1] the non-determinism in test_printf in > connection with Arpitha's work on rewriting it to kunit, this prompted > me to use test_printf as a first place to apply that principle, and > get the infrastructure in place that will avoid repeating the "module > parameter/seed the rnd_state/report the seed used" boilerplate in each > module. > > Shuah, assuming the kselftest_module.h changes are ok, I think it's > most natural if you carry these patches, though I'd be happy with any > other route as well. Completely in favour of this. Reviewed-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx> One note though. AFAIU the global variables are always being used in the modules that include the corresponding header. Otherwise we might have an extra warning(s). I believe you have compiled with W=1 to exclude other cases. > [1] https://lore.kernel.org/lkml/20200821113710.GA26290@alley/ > > > Rasmus Villemoes (4): > prandom.h: add *_state variant of prandom_u32_max > kselftest_module.h: unconditionally expand the KSTM_MODULE_GLOBALS() > macro > kselftest_module.h: add struct rnd_state and seed parameter > lib/test_printf.c: use deterministic sequence of random numbers > > Documentation/dev-tools/kselftest.rst | 2 -- > include/linux/prandom.h | 29 ++++++++++++++++ > lib/test_bitmap.c | 3 -- > lib/test_printf.c | 13 ++++--- > lib/test_strscpy.c | 2 -- > tools/testing/selftests/kselftest_module.h | 40 ++++++++++++++++++---- > 6 files changed, 72 insertions(+), 17 deletions(-) > > -- > 2.23.0 > -- With Best Regards, Andy Shevchenko
