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[209.85.208.48]) by smtp.gmail.com with ESMTPSA id 4fb4d7f45d1cf-5dc723cff72sm5080052a12.15.2025.02.01.16.58.43 for (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sat, 01 Feb 2025 16:58:44 -0800 (PST) Received: by mail-ed1-f48.google.com with SMTP id 4fb4d7f45d1cf-5d3e9a88793so4947784a12.1 for ; Sat, 01 Feb 2025 16:58:43 -0800 (PST) X-Forwarded-Encrypted: i=1; AJvYcCW5/r9jlFqNxs1oRNcQmI/p92pATIkc5Hmqtkx3fG1fkz231bT5CxJPkh/QcDcInnFosPEG0nyHnw==@kvack.org X-Received: by 2002:a05:6402:50ca:b0:5d9:a55:42ef with SMTP id 4fb4d7f45d1cf-5dc5efc4586mr20023222a12.17.1738457922880; Sat, 01 Feb 2025 16:58:42 -0800 (PST) MIME-Version: 1.0 References: <9035b82cff08a3801cef3d06bbf2778b2e5a4dba.1731684329.git.josef@toxicpanda.com> <20250131121703.1e4d00a7.alex.williamson@redhat.com> <20250201-legehennen-klopfen-2ab140dc0422@brauner> In-Reply-To: <20250201-legehennen-klopfen-2ab140dc0422@brauner> From: Linus Torvalds Date: Sat, 1 Feb 2025 16:58:26 -0800 X-Gmail-Original-Message-ID: X-Gm-Features: AWEUYZkrc1rbpsukghJrnBMXjfiiupnnm33djYsyEN114ENNjNC4tG_tthCj53k Message-ID: Subject: Re: [REGRESSION] Re: [PATCH v8 15/19] mm: don't allow huge faults for files with pre content watches To: Christian Brauner Cc: Peter Xu , Alex Williamson , Josef Bacik , kernel-team@fb.com, linux-fsdevel@vger.kernel.org, jack@suse.cz, amir73il@gmail.com, viro@zeniv.linux.org.uk, linux-xfs@vger.kernel.org, linux-btrfs@vger.kernel.org, linux-mm@kvack.org, linux-ext4@vger.kernel.org, "linux-kernel@vger.kernel.org" , "kvm@vger.kernel.org" Content-Type: text/plain; charset="UTF-8" X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: AC7CD180003 X-Stat-Signature: otuq5tc6yuwpn58qcdj88ztxpa384y9y X-Rspam-User: X-HE-Tag: 1738457926-97515 X-HE-Meta: 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 0cETdCWN 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.316233, 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 Sat, 1 Feb 2025 at 06:38, Christian Brauner wrote: > > Ok, but those "device fds" aren't really device fds in the sense that > they are character fds. They are regular files afaict from: > > vfio_device_open_file(struct vfio_device *device) > > (Well, it's actually worse as anon_inode_getfile() files don't have any > mode at all but that's beside the point.)? > > In any case, I think you're right that such files would (accidently?) > qualify for content watches afaict. So at least that should probably get > FMODE_NONOTIFY. Hmm. Can we just make all anon_inodes do that? I don't think you can sanely have pre-content watches on anon-inodes, since you can't really have access to them to _set_ the content watch from outside anyway.. In fact, maybe do it in alloc_file_pseudo()? Amir / Josef? Linus