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b=lRf1OwtyxAECl+Eaa0182Si5tY+rpvdgdW7IC6u6c6Jg4pURVBtxi7oU8rqXZgFdG linyfrNplUxCtEvNjGwlGetPNAuoJeCwq/esuWIPehYSaJ8kGS0gwvRK76cc60SXEI iFwbMU5/NKYMJyQ9SICvxnoGXNDkRBEyHvlmDLAbghYwFvS+uNdOnnmsD2mJ+NsLrF nzdhFMKGkMwQkj7vnuhIfgrYZWpuAegrdB4UUzsTZ/bl28qylovIYP8KeC5hIPev8I 9CCPg6Ud1HTxwpXK4KPV/wvvtf9h2CXHbWwIuGqPzSvfLx3xZ1ZwqM9H0YoJoe+UwU 2QC9uHpCDYptw== Message-ID: Date: Mon, 19 Jan 2026 12:09:07 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 6/8] selftests/mm: fix faulting-in code in pagemap_ioctl test To: Kevin Brodsky , linux-mm@kvack.org, linux-kselftest@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Andrew Morton , Lorenzo Stoakes , Mark Brown , Ryan Roberts , Shuah Khan , Usama Anjum References: <20260107164842.3289559-1-kevin.brodsky@arm.com> <20260107164842.3289559-7-kevin.brodsky@arm.com> From: "David Hildenbrand (Red Hat)" 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 B3JfpUqcWwE7vUaYrHG1nw54pLUoPG6sAA7Mehl3nd4pZUALHwARAQABzSREYXZpZCBIaWxk ZW5icmFuZCA8ZGF2aWRAa2VybmVsLm9yZz7CwY0EEwEIADcWIQQb2cqtc1xMOkYN/MpN3hD3 AP+DWgUCaKYhwAIbAwUJJlgIpAILCQQVCgkIAhYCAh4FAheAAAoJEE3eEPcA/4Naa5EP/3a1 9sgS9m7oiR0uenlj+C6kkIKlpWKRfGH/WvtFaHr/y06TKnWn6cMOZzJQ+8S39GOteyCCGADh 6ceBx1KPf6/AvMktnGETDTqZ0N9roR4/aEPSMt8kHu/GKR3gtPwzfosX2NgqXNmA7ErU4puf zica1DAmTvx44LOYjvBV24JQG99bZ5Bm2gTDjGXV15/X159CpS6Tc2e3KvYfnfRvezD+alhF XIym8OvvGMeo97BCHpX88pHVIfBg2g2JogR6f0PAJtHGYz6M/9YMxyUShJfo0Df1SOMAbU1Q Op0Ij4PlFCC64rovjH38ly0xfRZH37DZs6kP0jOj4QdExdaXcTILKJFIB3wWXWsqLbtJVgjR YhOrPokd6mDA3gAque7481KkpKM4JraOEELg8pF6eRb3KcAwPRekvf/nYVIbOVyT9lXD5mJn IZUY0LwZsFN0YhGhQJ8xronZy0A59faGBMuVnVb3oy2S0fO1y/r53IeUDTF1wCYF+fM5zo14 5L8mE1GsDJ7FNLj5eSDu/qdZIKqzfY0/l0SAUAAt5yYYejKuii4kfTyLDF/j4LyYZD1QzxLC MjQl36IEcmDTMznLf0/JvCHlxTYZsF0OjWWj1ATRMk41/Q+PX07XQlRCRcE13a8neEz3F6we 08oWh2DnC4AXKbP+kuD9ZP6+5+x1H1zEzsFNBFXLn5EBEADn1959INH2cwYJv0tsxf5MUCgh Cj/CA/lc/LMthqQ773gauB9mN+F1rE9cyyXb6jyOGn+GUjMbnq1o121Vm0+neKHUCBtHyseB fDXHA6m4B3mUTWo13nid0e4AM71r0DS8+KYh6zvweLX/LL5kQS9GQeT+QNroXcC1NzWbitts 6TZ+IrPOwT1hfB4WNC+X2n4AzDqp3+ILiVST2DT4VBc11Gz6jijpC/KI5Al8ZDhRwG47LUiu Qmt3yqrmN63V9wzaPhC+xbwIsNZlLUvuRnmBPkTJwwrFRZvwu5GPHNndBjVpAfaSTOfppyKB Tccu2AXJXWAE1Xjh6GOC8mlFjZwLxWFqdPHR1n2aPVgoiTLk34LR/bXO+e0GpzFXT7enwyvF FFyAS0Nk1q/7EChPcbRbhJqEBpRNZemxmg55zC3GLvgLKd5A09MOM2BrMea+l0FUR+PuTenh 2YmnmLRTro6eZ/qYwWkCu8FFIw4pT0OUDMyLgi+GI1aMpVogTZJ70FgV0pUAlpmrzk/bLbRk F3TwgucpyPtcpmQtTkWSgDS50QG9DR/1As3LLLcNkwJBZzBG6PWbvcOyrwMQUF1nl4SSPV0L LH63+BrrHasfJzxKXzqgrW28CTAE2x8qi7e/6M/+XXhrsMYG+uaViM7n2je3qKe7ofum3s4v q7oFCPsOgwARAQABwsF8BBgBCAAmAhsMFiEEG9nKrXNcTDpGDfzKTd4Q9wD/g1oFAmic2qsF CSZYCKEACgkQTd4Q9wD/g1oq0xAAsAnw/OmsERdtdwRfAMpC74/++2wh9RvVQ0x8xXvoGJwZ rk0Jmck1ABIM//5sWDo7eDHk1uEcc95pbP9XGU6ZgeiQeh06+0vRYILwDk8Q/y06TrTb1n4n 7FRwyskKU1UWnNW86lvWUJuGPABXjrkfL41RJttSJHF3M1C0u2BnM5VnDuPFQKzhRRktBMK4 GkWBvXlsHFhn8Ev0xvPE/G99RAg9ufNAxyq2lSzbUIwrY918KHlziBKwNyLoPn9kgHD3hRBa Yakz87WKUZd17ZnPMZiXriCWZxwPx7zs6cSAqcfcVucmdPiIlyG1K/HIk2LX63T6oO2Libzz 7/0i4+oIpvpK2X6zZ2cu0k2uNcEYm2xAb+xGmqwnPnHX/ac8lJEyzH3lh+pt2slI4VcPNnz+ vzYeBAS1S+VJc1pcJr3l7PRSQ4bv5sObZvezRdqEFB4tUIfSbDdEBCCvvEMBgoisDB8ceYxO cFAM8nBWrEmNU2vvIGJzjJ/NVYYIY0TgOc5bS9wh6jKHL2+chrfDW5neLJjY2x3snF8q7U9G EIbBfNHDlOV8SyhEjtX0DyKxQKioTYPOHcW9gdV5fhSz5tEv+ipqt4kIgWqBgzK8ePtDTqRM qZq457g1/SXSoSQi4jN+gsneqvlTJdzaEu1bJP0iv6ViVf15+qHuY5iojCz8fa0= In-Reply-To: <20260107164842.3289559-7-kevin.brodsky@arm.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Rspamd-Queue-Id: 6F4DDA0007 X-Stat-Signature: psyhdmih9k3phm9cscdt74edxcwuksy8 X-Rspam-User: X-Rspamd-Server: rspam05 X-HE-Tag: 1768820953-915625 X-HE-Meta: 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 nuSm2LLC rItnvT/H8EGCV9SUta+4xdgDLorfGV60nl2OqR5rkDWkb4bUEOWr5vTnhjciQAUSOQHYloV0z3t/2tPrq1qaWpTlJzUWSuSTmhJR1VKN2+ehhVh6TtPFOsXgpMlk9VCdjz2n2+tpGbswEAWAaxNm+Dy6gB3dEdH43ictLMme+iD3aDZj+j3dSJsyVaQr4YkxGm2vKYXO8bHdmZFAK0lnbbBjTvGbY2ExIt+LYBwOsFuzIypHBCxcMx4rc3oD8SPkL7dTNFfH9T+SE5UQW+pV9RrUJnpuLWDyim+uX+/ld+rVsPaGnOZyVHGaReKZ8LPDqYc+dcemHYrIJDAw= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 1/7/26 17:48, Kevin Brodsky wrote: > One of the pagemap_ioctl tests attempts to fault in pages by > memcpy()'ing them to an unused buffer. This probably worked > originally, but since commit 46036188ea1f ("selftests/mm: build with > -O2") the compiler is free to optimise away that unused buffer and > the memcpy() with it. As a result there might not be any resident > page in the mapping and the test may fail. Yes, I assume so. Using FORCE_READ() etc is the way to go. Should we add Fixes: 46036188ea1f ("selftests/mm: build with -O2") ? Acked-by: David Hildenbrand (Red Hat) -- Cheers David