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imf01.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=KfXib73j; spf=pass (imf01.hostedemail.com: domain of david@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=david@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1778572670; a=rsa-sha256; cv=none; b=qeSqSnQqGAvVITJpIqLlEIqgyq9eiAZ0+9TKp48P6Vtoxo5BPg87QoSieXbIWDBBi0urqR yeB7zg3p15R8Tf9DNipft6rZRrAmVVrz8lWiGEGBtCPyxyG3UP8Alj5WOr8U+bf+ScJV18 a6tV0yD0tWWLyDo8OujyxH95ii6ZSHE= Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by sea.source.kernel.org (Postfix) with ESMTP id EF974407ED; Tue, 12 May 2026 07:57:48 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9E0C8C2BCB8; Tue, 12 May 2026 07:57:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1778572668; bh=ssGnryp0Yilk56LJoxUY5bwY6rU1fYkeibtaHfhOsT4=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=KfXib73jarYe2Lr4MOreoqXOU5BgAIHmuRo+D6yRfWhQ7dMNDXdrCKBJUDoxusY8k T8ErtVIZKfoG7ddAv0ooRdp49Cy6VbKilu4bzrOKb5iDWUyKf9wPJLNryvQu8UtDsl A7kNI9oyhtUHUSQY1RUViCf1FLnoKCj4UbKJJB+AXrz0G9101ufHdxsv+qv2aOuiWx Ty7Y1/o5I9cqayGNqRGgfWIi7NLl2Ii5NG5/fKFYFPsGzLOgdgSG3AloMWf1n7OxXV zVWzNnKrZe9G9jUFZNc1/cfyBMKR3l7w0RQSaE/64Zg1VPTGLrjSLP4hyQC6iwhrPj eyMenNlBdIy3g== Message-ID: Date: Tue, 12 May 2026 09:57:46 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] selftests/mm: check file initialization writes in split_huge_page_test To: Vineet Agarwal , akpm@linux-foundation.org Cc: ljs@kernel.org, linux-mm@kvack.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org References: <20260512074924.27721-1-agarwal.vineet2006@gmail.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: <20260512074924.27721-1-agarwal.vineet2006@gmail.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspam-User: X-Rspamd-Server: rspam10 X-Rspamd-Queue-Id: EEF214000D X-Stat-Signature: onkafpthrbenu8h1z4gdf3z4brxenqmp X-HE-Tag: 1778572669-123852 X-HE-Meta: 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 SX566f1m 5h0mcuTJn0GEQjjQd2rEPwGvN/a3Y1HcNmldqEw6v3KLOEz9i2KEr/RU3cIv51YQ5oDerXtwzFDkqPUUsKurQHYicdSgx6KZkG9/UkGQYRPrSHtPkQGrwLvI7mpc3LQt5oyXnsuDy8ydc4i1uwAMk/DIfTtazUFaHf0ECsJPnHWNvaL2rlhN2IyfI+CkcBwd/g3yiDcrCfnL7H9g2aHz/9azPp0qMyYZ+/mOwqiPD6EOJDkZyc/1r4bBeTYtCgPUmJUAe3xUQ425jjpmp9sGnM2HYq+2CLiCS5IgPlFc3sA1l3fvTEijIYx1YmjbjG1FzCQVqozTvy9osd1ogzMmSKC6PKn2w0XjE102AmC2GaGn0rU9NKPfO8BM6Ab3RhTVsGFVAgFWAN/Z2w9r+xYZjVySUdYC29FSipM9Mzt29bYLPBAM= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 5/12/26 09:49, Vineet Agarwal wrote: > create_pagecache_thp_and_fd() fills the backing file for the > pagecache THP tests using repeated write() calls, but the return > value is never checked. > > If a write fails or completes only partially, the test may continue > with an incompletely initialized file and produce misleading results. > > Check the result of write() and fail the test if the expected number > of bytes was not written. > > Signed-off-by: Vineet Agarwal > --- > tools/testing/selftests/mm/split_huge_page_test.c | 13 ++++++++++--- > 1 file changed, 10 insertions(+), 3 deletions(-) > > diff --git a/tools/testing/selftests/mm/split_huge_page_test.c b/tools/testing/selftests/mm/split_huge_page_test.c > index 500d07c4938b..eab69b0f59a0 100644 > --- a/tools/testing/selftests/mm/split_huge_page_test.c > +++ b/tools/testing/selftests/mm/split_huge_page_test.c > @@ -609,9 +609,16 @@ static int create_pagecache_thp_and_fd(const char *testfile, size_t fd_size, > assert(fd_size % sizeof(buf) == 0); > for (i = 0; i < sizeof(buf); i++) > buf[i] = (unsigned char)i; > - for (i = 0; i < fd_size; i += sizeof(buf)) > - write(*fd, buf, sizeof(buf)); > - > + for (i = 0; i < fd_size; i += sizeof(buf)) { > + ssize_t written; Do you really need the temporary variable? > + > + written = write(*fd, buf, sizeof(buf)); > + if (written != sizeof(buf)) { > + ksft_perror("write testfile"); > + close(*fd); > + goto err_out_unlink; > + } > + } > close(*fd); > sync(); > *fd = open("/proc/sys/vm/drop_caches", O_WRONLY); Apart from that LGTM Acked-by: David Hildenbrand (Arm) -- Cheers, David