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Mon, 17 Nov 2025 09:31:35 -0800 (PST) MIME-Version: 1.0 References: <20251113034623.3127012-1-cmllamas@google.com> <4a60a703-d9c2-46a8-83b4-a7ecff7f6ba2@lucifer.local> <20251113153205.6507ecb308e7d09362905da7@linux-foundation.org> <9d30836b-9ddb-4432-aa39-85e32c2ea645@kernel.org> <20251114143909.14ecee31b88f179bc2858e30@linux-foundation.org> In-Reply-To: <20251114143909.14ecee31b88f179bc2858e30@linux-foundation.org> From: Ujwal Kundur Date: Mon, 17 Nov 2025 23:01:22 +0530 X-Gm-Features: AWmQ_blYT_0n6-EoSgb5vkK1TfvHayH6Eh8aX8bnaH1niORp_lD21yGSPt8taXc Message-ID: Subject: Re: [PATCH] selftests/mm: fix division-by-zero in uffd-unit-tests To: Andrew Morton Cc: "David Hildenbrand (Red Hat)" , Lorenzo Stoakes , Carlos Llamas , Peter Xu , "Liam R. Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Shuah Khan , Brendan Jackman , kernel-team@android.com, linux-kernel@vger.kernel.org, stable@vger.kernel.org, "open list:MEMORY MANAGEMENT - USERFAULTFD" , "open list:KERNEL SELFTEST FRAMEWORK" Content-Type: text/plain; charset="UTF-8" X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: 636791C001B X-Stat-Signature: szg71k1t8xydk1zbrx79t7uk17nnn5m7 X-Rspam-User: X-HE-Tag: 1763400697-989136 X-HE-Meta: U2FsdGVkX18+a0D3x7e53mzZOPOEHQ8yJ8UVwJqV3knDnr0ODTJxhtu3OtZKBXuyousclAy2ghyyYvHbYG4M0PFVXfp6+HPHGReNJXN9+Jebn8ae00nY3XCSD+IejDG3++SfqfHjF/M1jT9fL0tyWNEaS6kqgzXNGE2rcqcMF7exJ6nXg7dPXSQjIrxVoMz+I8Ui+JoRxOliCiMS24ijdIUifb2kGJYjoHEaxt1MoMI1DpEAW7cRQk2FuF8Feq7eGGBRi6UcZe+YQnp6rEBAtVFWOc46VgHtDFsxLBRc2EUmYeZIsfDudswJ5mH69uhZgsmQB0UvPc9YmUV5/Pbm0eygd9NE3mQf6l16mO/P0BnqS9vvvHDnjQE5fCSIdyyGfH+3ERMaCwW06y8YAwjAcHlkvv0zG1R1ZagqTISipqJKYCbiBQhqDAsH9+VydLEr2A5E2b049Z2aVVzCRBqe/4wWm/bSDJZjjOVTHvlS0reAZJIjn2duxcoI4bO/XpMsZt583nPos+Ygi9EYiD+cncS1Fe4sNEgDWUnBp9ARBSNNr474Ei+WTi7Q5UDrTq98hBFpXOzPiaeKRsB28C2y9QzpHW6rpICCGy3pWXTLjxuOfcaHdlvOz736TgeU3hZY3eq7RvayF50JDDhqrEzX1l8NyxuOHyAS6R/UFpauuQDN3to0uAby7IJIfNOAaRR2T2tA37hbfqjxJtWCSegx7/VQtdN1yVjU8ccmaGaV/xYibE0Qv7R9Z8RI0EL61aOaursRZY1Cz8OXdR5EvEb7jUWku3aTOeAeUMffSyoVaUUKcnaToV9pVVxtfozfzWxMBo1EvjI1SkwmztQvKvW5oVCpCGQG01EEMD0gCmr3Y8ZBvU1Ha928iWYNGT6QLdjWtWStkSdbmlVQj3/J1Hwrg9SsBMsFHezlfvIONfukq0PYTkns56eT2DU61CgxX5heDNwYhLPgOUWv4famTFX 1pSamvzx 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 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: > Commit 4dfd4bba8578 ("selftests/mm/uffd: refactor non-composite global > vars into struct") moved some of the operations previously implemented > in uffd_setup_environment() earlier in the main test loop. > The calculation of nr_pages, which involves a division by page_size, now > occurs before checking that default_huge_page_size() returns a non-zero > This leads to a division-by-zero error on systems with !CONFIG_HUGETLB. > Fix this by relocating the non-zero page_size check before the nr_pages > calculation, as it was originally implemented. Thanks for the fix! I never tested with CONFIG_HUGETLB turned off. We now need tests for tests :) Reviewed-by: Ujwal Kundur