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b=PmqFbsFUTG/9rSVRaADA2eVRe0zrojnWiuS374tRO6aCxI/ZVdQLX8e1K4i/nLlqN lIr6CMk1lESf0eWaX/A081nMU48DMCkU88urF9KIsBgowmy7H18VGxqIVfJsBXN6pn H28DoxSdOnPYxlU25pS0exa50Iph12eSYIJlEjUhTBijblJ2y4ZXFockuXxtRIe0Ag qTd/vWY+GZ/XvYlcvUreNQKnj7hp8muwIJRIEwIy3k03JqjI1wDW/ft3SzxkbBgmHo R4jLl9AG6Q1fNpjkfjYQ8m/d+Zo6P38xoFm2psivujM/hFsHbTNXSXkSBXJyfsiPGf 3M4Ix9DDhC7DA== Message-ID: <7f729e75-dd66-49ea-ab5f-408fdc1a5c81@kernel.org> Date: Tue, 28 Apr 2026 12:06:14 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2] selftests/mm: khugepaged: initialize file contents via mmap To: Vineet Agarwal Cc: akpm@linux-foundation.org, ljs@kernel.org, shuah@kernel.org, linux-mm@kvack.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org References: <3abf09d8-a98e-4f1b-b8d9-77879a8a2733@kernel.org> <20260428094356.60415-1-agarwal.vineet2006@gmail.com> <548dc617-ca19-45f6-852f-adebcf8d3a11@kernel.org> From: "David Hildenbrand (Arm)" Content-Language: en-US Autocrypt: addr=david@kernel.org; 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Without resizing it first, mapping > and accessing the full range can go beyond EOF. Ah, that makes sense, worth spelling it out. Indeed, we otherwise get $ sudo ./khugepaged madvise:file . Save THP and khugepaged settings... OK Allocate huge page on fault... OK Split huge PMD on MADV_DONTNEED... OK Run test: collapse_full (madvise:file) Creating ./collapse_test_file for collapse...Bus error -- Cheers, David