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Wong" , SHAURYA RANE , akpm@linux-foundation.org, shakeel.butt@linux.dev, eddyz87@gmail.com, andrii@kernel.org, ast@kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-kernel-mentees@lists.linux.dev, skhan@linuxfoundation.org, david.hunter.linux@gmail.com, khalid@kernel.org, syzbot+09b7d050e4806540153d@syzkaller.appspotmail.com, bpf Subject: Re: [PATCH] mm/filemap: fix NULL pointer dereference in do_read_cache_folio() Message-ID: References: <20251114193729.251892-1-ssranevjti@gmail.com> <20251117164155.GB196362@frogsfrogsfrogs> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html X-Rspamd-Server: rspam09 X-Rspamd-Queue-Id: D729740009 X-Stat-Signature: cnywaoz99a5jme61xy9hdyt8qezatdxi X-Rspam-User: X-HE-Tag: 1763531461-621163 X-HE-Meta: U2FsdGVkX18+KZylsw4pdTiAU0IzWhBY+Rwf7BUCpP+ZUL6Fveu/JsX7LJub3aWR4FnR1KNJwthCXEE/ifXC+BhT2411mH+FEW3hA/Uzm3j4+hfjRVAhBCqzwgVV7DA+TzaA4pxmIBSTpsGjhEj/Rrmfs0qMfUS4vpDNm6tlpPs3C/fqmYEmWMTzeI337XZucQOYlQLFnFTnuS8UVpuf9nCfq5ngnOPMkGD6GT8uQ/PcUHyJmc9oUwF7lTpy1w1bds4I8MAO5nDQiBpPMgbWh4kxBkD9Uf9A/0QGr67W7gzVJ9XN330zlrzDHI6JpJbZ29G70pEnvKjCKNnwpB6fAmaMgGAzWdoJYf76l4qkZinj+UaWfgEfYD45SPHLUibk2HkLN5WkZ3eDSyUnterGn1veXcfyphRtifoLbf0erIiWIv4kZERV6yNeiMlIX6GEXXJcb6ei5cZLTsxEdB4vAiHlHHywI4j0/HXkROt6FwWYxY8tLSzy81WzbK+5iuYkKmPfLAZA51A9B+b6KNpR9/YxJEABI/DtE+S6bwZE06Mw1fpaPcYjJjuwffJggNcgvk8pZV+VBo/Y9RfhPhizs4jynXXDSFtsNGN2VL1cPi3ZZrm/8wvvqaGyG4lrEtw0Pdr/VJu/QMbUJhqa3bVdu6+2JeysjeFRAZ7JPNw2/xEbq1127sCfo8Pr84SOzW5o8Kdb5nv2fSogh/xaAcSm9bwDMcTOuzM2qB3pY4qZblBJ9EYnaEoFtVLM+VQO7blzvxXsh608vuimDRzVWCaHke7rQghsYQDvsmu/gVEwyf4mhK+2ZRaCcZXoVM0CrFxfE5wr9+nL8akyBGC+6mhmuffmqeTn+/2MHHvSPwL3zHrF5kCSleGlsPT+BsZtT7bvJBxFRNiZVzwVGVJZsfhjm5Rhi9w9l8JxtrX4j+zH0bm52ibDab8mamnQ4IVSiN6lOVy2Gm9VDjEHsZyDpR5 d59ZRi+p 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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: On Tue, Nov 18, 2025 at 11:27:47AM -0800, Andrii Nakryiko wrote: > Then please help make it better, give us interfaces you think are > appropriate. People do use this functionality in production, it's > important and we are not going to drop it. In non-sleepable mode it's > best-effort, if the requested part of the file is paged in, we'll > successfully read data (such as ELF's build ID), and if not, we'll > report that to the BPF program as -EFAULT. In sleepable mode, we'll > wait for that part of the file to be paged in before proceeding. > PROCMAP_QUERY ioctl() is always in sleepable mode, so it will wait for > file data to be read. That's pretty demanding: "If you don't give me the interface that I want I'll just poke into internals and do broken shit" isn't really the best way to make friends and win influence., > If you don't like the implementation, please help improve it, don't > just request dropping it "because BPF folks" or anything like that. Again, you're trying to put a lot of work you should have done on others. Everyone here is pretty helpful guiding when asking for help, but being asked at gunpoint to cleanup the mess your created is not going to get everyone drop their work and jump onto your project.