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 A08673F4DDC; Tue, 11 Aug 2026 16:11:11 +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=1786464673; cv=none; b=ewlsVLmCcZRGjRDsx96RKgV2xtYTM6DQC7Dd76fvzmog29AwgoHi9uOAbz2wVrBuNWJjl2FgJ9oD/3bsr6djVSAUNk9GFNcdgyMju0EnwFA2uceAYaeMaTF/RWaUIl/0V1OjavUyyE/kU9iOhw7jocKrVdAnAMHehPWs53w2Ua4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786464673; c=relaxed/simple; bh=Q7P5tdRF64kaESCPCVNKTW7zKQP1WTOuJUymFKeK1pk=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=okQH76wjaP3gTYWpzEpzoiwR1gF+07gb1QrKCw7lYKrLqAJKu2binG9DWchBVHSyHAUizOF05aAgLW3yBfqsYpvx8j/X+Z2giqppWdAhc5nPCB2gGm7W8hRBfbz8j0HijG0fjZ3A0VnhzVQ5wYdL6fqPN4NEnYdDdDQxLCiP88A= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=jMjLXqCO; 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="jMjLXqCO" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 728441F000E9; Tue, 11 Aug 2026 16:11:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1786464671; bh=Un/OfXb3LOyN540R6UlGcb5CTwWvA8koOuzxF4qHLao=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=jMjLXqCObthVZJds8KrwkJZ8tG5aCvdK6chypyAltVhQgquuxxqwD8Fzn2Ha2ux+4 xd0LOndlPKYnD5c8PUDY/IGJa+cfz9/5Fyq8j9gqBg5m52VYrBlpA6Ki04Xd8Rc2ZB Tkk5S0MIF1BwLc1xP5NMqtv0iEUG3YQEWIgfQr76LuiNTNGNcuJkoQGzNIXfTC7lBT tNbXExTKLQLJ5ITFP54eBbfdkefM32H8BOhQwfUmZKcEQOfCCU+jBU4EZNBWMfaIqi DfWC62ShGtIj2LNVrmfXfJ1Llhym9HpP/BVIPMIBc+Kay1xcjlexlcgvX5SC+xb2eo UaraW2d0LIuDw== Message-ID: Date: Tue, 11 Aug 2026 18:11:04 +0200 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 2/2] selftests/mm: Fix soft-dirty kselftest supported check To: Audra Mitchell Cc: jocolema@redhat.com, raquini@redhat.com, Andrew Morton , Lorenzo Stoakes , "Liam R. Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Shuah Khan , Colin Ian King , Muhammad Usama Anjum , Andrei Vagin , linux-mm@kvack.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org References: <7d6b4401-e230-4ca7-b64f-c1277fa643b8@kernel.org> <20260806181843.1839943-1-audra@redhat.com> <20260806181843.1839943-3-audra@redhat.com> From: "David Hildenbrand (Arm)" Content-Language: en-US Autocrypt: addr=david@kernel.org; keydata= xsFNBFXLn5EBEAC+zYvAFJxCBY9Tr1xZgcESmxVNI/0ffzE/ZQOiHJl6mGkmA1R7/uUpiCjJ dBrn+lhhOYjjNefFQou6478faXE6o2AhmebqT4KiQoUQFV4R7y1KMEKoSyy8hQaK1umALTdL QZLQMzNE74ap+GDK0wnacPQFpcG1AE9RMq3aeErY5tujekBS32jfC/7AnH7I0v1v1TbbK3Gp XNeiN4QroO+5qaSr0ID2sz5jtBLRb15RMre27E1ImpaIv2Jw8NJgW0k/D1RyKCwaTsgRdwuK Kx/Y91XuSBdz0uOyU/S8kM1+ag0wvsGlpBVxRR/xw/E8M7TEwuCZQArqqTCmkG6HGcXFT0V9 PXFNNgV5jXMQRwU0O/ztJIQqsE5LsUomE//bLwzj9IVsaQpKDqW6TAPjcdBDPLHvriq7kGjt WhVhdl0qEYB8lkBEU7V2Yb+SYhmhpDrti9Fq1EsmhiHSkxJcGREoMK/63r9WLZYI3+4W2rAc UucZa4OT27U5ZISjNg3Ev0rxU5UH2/pT4wJCfxwocmqaRr6UYmrtZmND89X0KigoFD/XSeVv jwBRNjPAubK9/k5NoRrYqztM9W6sJqrH8+UWZ1Idd/DdmogJh0gNC0+N42Za9yBRURfIdKSb B3JfpUqcWwE7vUaYrHG1nw54pLUoPG6sAA7Mehl3nd4pZUALHwARAQABzS5EYXZpZCBIaWxk ZW5icmFuZCAoQ3VycmVudCkgPGRhdmlkQGtlcm5lbC5vcmc+wsGQBBMBCAA6AhsDBQkmWAik AgsJBBUKCQgCFgICHgUCF4AWIQQb2cqtc1xMOkYN/MpN3hD3AP+DWgUCaYJt/AIZAQAKCRBN 3hD3AP+DWriiD/9BLGEKG+N8L2AXhikJg6YmXom9ytRwPqDgpHpVg2xdhopoWdMRXjzOrIKD g4LSnFaKneQD0hZhoArEeamG5tyo32xoRsPwkbpIzL0OKSZ8G6mVbFGpjmyDLQCAxteXCLXz ZI0VbsuJKelYnKcXWOIndOrNRvE5eoOfTt2XfBnAapxMYY2IsV+qaUXlO63GgfIOg8RBaj7x 3NxkI3rV0SHhI4GU9K6jCvGghxeS1QX6L/XI9mfAYaIwGy5B68kF26piAVYv/QZDEVIpo3t7 /fjSpxKT8plJH6rhhR0epy8dWRHk3qT5tk2P85twasdloWtkMZ7FsCJRKWscm1BLpsDn6EQ4 jeMHECiY9kGKKi8dQpv3FRyo2QApZ49NNDbwcR0ZndK0XFo15iH708H5Qja/8TuXCwnPWAcJ DQoNIDFyaxe26Rx3ZwUkRALa3iPcVjE0//TrQ4KnFf+lMBSrS33xDDBfevW9+Dk6IISmDH1R HFq2jpkN+FX/PE8eVhV68B2DsAPZ5rUwyCKUXPTJ/irrCCmAAb5Jpv11S7hUSpqtM/6oVESC 3z/7CzrVtRODzLtNgV4r5EI+wAv/3PgJLlMwgJM90Fb3CB2IgbxhjvmB1WNdvXACVydx55V7 LPPKodSTF29rlnQAf9HLgCphuuSrrPn5VQDaYZl4N/7zc2wcWM7BTQRVy5+RARAA59fefSDR 9nMGCb9LbMX+TFAoIQo/wgP5XPyzLYakO+94GrgfZjfhdaxPXMsl2+o8jhp/hlIzG56taNdt VZtPp3ih1AgbR8rHgXw1xwOpuAd5lE1qNd54ndHuADO9a9A0vPimIes78Hi1/yy+ZEEvRkHk /kDa6F3AtTc1m4rbbOk2fiKzzsE9YXweFjQvl9p+AMw6qd/iC4lUk9g0+FQXNdRs+o4o6Qvy iOQJfGQ4UcBuOy1IrkJrd8qq5jet1fcM2j4QvsW8CLDWZS1L7kZ5gT5EycMKxUWb8LuRjxzZ 3QY1aQH2kkzn6acigU3HLtgFyV1gBNV44ehjgvJpRY2cC8VhanTx0dZ9mj1YKIky5N+C0f21 zvntBqcxV0+3p8MrxRRcgEtDZNav+xAoT3G0W4SahAaUTWXpsZoOecwtxi74CyneQNPTDjNg azHmvpdBVEfj7k3p4dmJp5i0U66Onmf6mMFpArvBRSMOKU9DlAzMi4IvhiNWjKVaIE2Se9BY FdKVAJaZq85P2y20ZBd08ILnKcj7XKZkLU5FkoA0udEBvQ0f9QLNyyy3DZMCQWcwRuj1m73D sq8DEFBdZ5eEkj1dCyx+t/ga6x2rHyc8Sl86oK1tvAkwBNsfKou3v+jP/l14a7DGBvrmlYjO 59o3t6inu6H7pt7OL6u6BQj7DoMAEQEAAcLBfAQYAQgAJgIbDBYhBBvZyq1zXEw6Rg38yk3e EPcA/4NaBQJonNqrBQkmWAihAAoJEE3eEPcA/4NaKtMQALAJ8PzprBEXbXcEXwDKQu+P/vts IfUb1UNMfMV76BicGa5NCZnJNQASDP/+bFg6O3gx5NbhHHPeaWz/VxlOmYHokHodOvtL0WCC 8A5PEP8tOk6029Z+J+xUcMrJClNVFpzVvOpb1lCbhjwAV465Hy+NUSbbUiRxdzNQtLtgZzOV Zw7jxUCs4UUZLQTCuBpFgb15bBxYZ/BL9MbzxPxvfUQIPbnzQMcqtpUs21CMK2PdfCh5c4gS sDci6D5/ZIBw94UQWmGpM/O1ilGXde2ZzzGYl64glmccD8e87OnEgKnH3FbnJnT4iJchtSvx yJNi1+t0+qDti4m88+/9IuPqCKb6Stl+s2dnLtJNrjXBGJtsQG/sRpqsJz5x1/2nPJSRMsx9 5YfqbdrJSOFXDzZ8/r82HgQEtUvlSXNaXCa95ez0UkOG7+bDm2b3s0XahBQeLVCH0mw3RAQg r7xDAYKIrAwfHHmMTnBQDPJwVqxJjVNr7yBic4yfzVWGCGNE4DnOW0vcIeoyhy9vnIa3w1uZ 3iyY2Nsd7JxfKu1PRhCGwXzRw5TlfEsoRI7V9A8isUCoqE2Dzh3FvYHVeX4Us+bRL/oqareJ CIFqgYMyvHj7Q06kTKmauOe4Nf0l0qEkIuIzfoLJ3qr5UyXc2hLtWyT9Ir+lYlX9efqh7mOY qIws/H2t In-Reply-To: <20260806181843.1839943-3-audra@redhat.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 8/6/26 20:17, Audra Mitchell wrote: > On architectures with separate user address space, such as s390 or > those without an MMU, the soft-dirty kselftest may fail when checking > to see if the feature is supported. > > # -------------------- > # running ./soft-dirty > # -------------------- > # TAP version 13 > # 1..15 > # Bail out! PAGEMAP_SCAN succeeded unexpectedly > # # Totals: pass:0 fail:0 xfail:0 xpass:0 skip:0 error:0 > # [FAIL] > not ok 1 soft-dirty # exit=1 > # SUMMARY: PASS=0 SKIP=0 FAIL=1 > > The soft-dirty test will initate an ioctl with the PAGEMAP_SCAN flag with > an invalid address for the page_region. This is done intentionally to > have the ioctl return with an expected EFAULT and with the correct > categories returned. > > However, on architectures with separate user address space, such as s390 or > those without an MMU, the call to __access_ok (used to validate the > variables provided with the ioctl) will always return true and we will not > fail as expected. > > if (IS_ENABLED(CONFIG_ALTERNATE_USER_ADDRESS_SPACE) || > !IS_ENABLED(CONFIG_MMU)) > return true; > > Let's simplify the check for PAGEMAP_SCAN and provide a valid page_region > address so that we get a non-errno return if it is supported. > > Fixes: 600bca580579 ("selftests/mm: check that PAGEMAP_SCAN returns correct categories") > > Signed-off-by: Audra Mitchell > --- > tools/testing/selftests/mm/vm_util.c | 23 ++++++++++++++--------- > 1 file changed, 14 insertions(+), 9 deletions(-) > > diff --git a/tools/testing/selftests/mm/vm_util.c b/tools/testing/selftests/mm/vm_util.c > index 6b65bd0a1e0b..4a8e339a7403 100644 > --- a/tools/testing/selftests/mm/vm_util.c > +++ b/tools/testing/selftests/mm/vm_util.c > @@ -66,20 +66,25 @@ static uint64_t pagemap_scan_get_categories(int fd, char *start) > } > > /* `start` is any valid address. */ Acked to dropping that. > -static bool pagemap_scan_supported(int fd, char *start) > +static bool pagemap_scan_supported(int fd) > { > + const size_t pagesize = getpagesize(); > static int supported = -1; > - int ret; > + struct page_region r; > + void *test_area; > > if (supported != -1) > return supported; > > - /* Provide an invalid address in order to trigger EFAULT. */ > - ret = __pagemap_scan_get_categories(fd, start, (struct page_region *) ~0UL); > - if (ret == 0) > - ksft_exit_fail_msg("PAGEMAP_SCAN succeeded unexpectedly\n"); > - > - supported = errno == EFAULT; > + test_area = mmap(0, pagesize, PROT_READ | PROT_WRITE, > + MAP_ANONYMOUS | MAP_PRIVATE, -1, 0); > + if (test_area == MAP_FAILED) { > + ksft_print_msg("WARN: mmap() failed: %s\n", strerror(errno)); > + supported = 0; You can really just ksft_exit_fail_msg("mmap() failed\n"); here, because this is one of the things that really should never fail. Which leaves us with: test_area = mmap(0, pagesize, PROT_READ | PROT_WRITE, MAP_ANONYMOUS | MAP_PRIVATE, -1, 0); if (test_area == MAP_FAILED) ksft_print_msg("WARN: mmap() failed: %s\n", strerror(errno)); supported = __pagemap_scan_get_categories(fd, test_area, &r) >= 0; munmap(test_area, pagesize); -- Cheers, David