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[5.186.115.188]) by smtp.gmail.com with ESMTPSA id k18sm4115867eds.93.2020.10.25.14.48.45 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 25 Oct 2020 14:48:46 -0700 (PDT) From: Rasmus Villemoes To: Shuah Khan , Kees Cook Cc: Petr Mladek , Willy Tarreau , linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org, Arpitha Raghunandan <98.arpi@gmail.com>, Andy Shevchenko , Brendan Higgins , Rasmus Villemoes Subject: [PATCH 0/4] deterministic random testing Date: Sun, 25 Oct 2020 22:48:38 +0100 Message-Id: <20201025214842.5924-1-linux@rasmusvillemoes.dk> X-Mailer: git-send-email 2.23.0 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org 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. [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