From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 49F643E6DD2; Tue, 25 Aug 2026 08:37:50 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787647072; cv=none; b=U9yDMra15DYDVRw3KTpGy7Wpr/+Y0Jr/hqN6Ev/YZxdOnoxCqZ1DNgjcISPa911RekXH0im5mu3p8lw9qKCN1803Hg4f1aON/kuHRwZ+ab9znAa4x67i34ELpDvHof4fiKRvM850k7ljGNrnHv+jsThYVnfM9k8n5mKMlF9rOcw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787647072; c=relaxed/simple; bh=+qGab7hN0sGivwq2mXB2sEMCzxrIrFtJf0CG8z91FvE=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=JPQejzF1mFvuV1BBtS2RZDplfQiSXxhejj0pKSdWINc6/2AiJ+TmqkFmsCoSLjzqqQn6CNvTt1izRgHctehulZqs60ZhGM8s3/uBx/e1rgpX4l1l8n7stpjHZllQyKlqQqa/TmeCZL8zfQ/+/47ox/qzyYJ8FJCWijg0W9woyEI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Z//QVUE1; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Z//QVUE1" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7C1B51F000E9; Tue, 25 Aug 2026 08:37:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1787647069; bh=9COt1w3P1MdstF38GuaEny+JKaDo98J8bEQBshdYhKo=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=Z//QVUE1GnHBGMaWgJTJyKF7qhlNX9G/P1wEgSjJPMjcxdPbi8Iv2wQVGKz5UUDdo 4zpFVmESnVz4I3S2DT764lLMxbRFjktGsFau54l92KImS2rU0NMZJv1hSdvybY0Xg5 DZUCgvw5u/4bEGE2kV5+9ea/ans6d0rYLQofsBg582EX2Okl+bfym5HF/DOgijOZTv Op8yakmihGw+NiVEkZPqyLHzxwYNl1nvPRghurehhDSdb4ngiZRWYbcOyYAqWRZCoM hwO2+QPg+mTQ4xZ7bJJsEtmTJScmBjnhbovLqbwVh8MaRIxAZTbprx7VPpwsdeCED9 pVLQy1kX0XuTw== Message-ID: Date: Tue, 25 Aug 2026 10:37:41 +0200 Precedence: bulk X-Mailing-List: linux-doc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 0/2] support kselftest on nommu platform To: Hajime Tazaki , linux-mm@kvack.org, liam@infradead.org, rbm@suse.com, akpm@linux-foundation.org, luto@amacapital.net, brendan.jackman@linux.dev, liuhangbin@gmail.com, corbet@lwn.net, kees@kernel.org, ljs@kernel.org, broonie@kernel.org, mhocko@suse.com, rppt@kernel.org, shuah@kernel.org, surenb@google.com, vbabka@kernel.org, wad@chromium.org, linux-doc@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-um@lists.infradead.org Cc: geert@linux-m68k.org, daniel@thingy.jp References: <20260825015945.141739-1-thehajime@gmail.com> From: "David Hildenbrand (Arm)" Content-Language: en-US Autocrypt: addr=david@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 7bit On 8/25/26 03:59, Hajime Tazaki wrote: > We add an ability to execute kselftest on nommu platforms. > > Currently there are several issues if we wish to run kselftests on nommu > targets: > > - it cannot compile/build test binaries because the current files mainly > assume to build with glibc, > - some of the tests are not able to run on nommu targets as there are no > fork(2) syscall. > > The first issue can be avoided if we can build static PIE binaries (if > targets support it), but in our case (build on ubuntu/glibc and run on > alpine/musl-libc), it fails to invoke due to lack of the GNU ifunc > mechanism. Thus, we need to cross-compile with musl toolchain, which > needs to be solved the first issue. > > The second issue is the lack of fork(2) syscall on those platforms. > Especially the test harness helper (kselftest_harness.h) uses the > syscall, which cannot be simply with vfork(2). `timeout` command used > in `runner.sh` never works for nommu platform as it uses fork(2). > > nommu component in the mm subsystem has several known issues and having > test cases should help this situation, thus this patchset is very first > step toward enriching test environment which has not been well tested > for a while. The test cases is implemented based on the document > (Documentation/admin-guide/mm/nommu-mmap.rst). > > So, for the first step, nommu targets only support low-level API of > kselftests (kselftest.h), and implement tests in a new target, > TARGETS=mm/nommu. Other targets are currently not even able to build > due to toolchain issues but will be addressed once the initial > introduction which mainly focuses on nommu test will be settled. > > The patch was initially combined with other patches but is decoupled to > only focus on test framework and testcases. > > - rfc: > https://lore.kernel.org/linux-mm/20260813063401.1786548-1-thehajime@gmail.com/ > > Hajime Tazaki (2): > selftests: run tests on nommu architecture > selftests/mm: add nommu mmap and mremap behavior tests > > Documentation/dev-tools/kselftest.rst | 14 + > tools/testing/selftests/Makefile | 1 + > tools/testing/selftests/kselftest/runner.sh | 9 +- > tools/testing/selftests/kselftest_harness.h | 4 + > tools/testing/selftests/lib.mk | 8 + > tools/testing/selftests/mm/nommu/Makefile | 7 + > .../selftests/mm/nommu/nommu_mmap_test.c | 265 +++++++++++++ > .../selftests/mm/nommu/nommu_mremap_test.c | 353 ++++++++++++++++++ That's odd. tools/testing/selftests/mm itself should know which tests can be built and ran on nommu. nommu-only tests can be placed in mm/nommu, but I would expect tools/testing/selftests/mm's Makefile and run script to compile and run only selftests that are supported on the given platform. -- Cheers, David