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[80.187.86.54]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-4bb4e2538b9sm244439965e9.1.2026.11.13.02.25.58 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 13 Nov 2026 02:25:59 -0800 (PST) Message-ID: Subject: Re: [PATCH RFC 38/41] fuse: refuse files on pseudo filesystems as passthrough backing files From: Alexander Mikhalitsyn To: Christoph Hellwig , Christian Brauner Cc: linux-fsdevel@vger.kernel.org, Jann Horn , Chris Mason , Josef Bacik , linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, linux-nvme@lists.infradead.org, Alexander Viro , Jan Kara , linux-scsi@vger.kernel.org, target-devel@vger.kernel.org, driver-core@lists.linux.dev, linux-mm@kvack.org, bpf@vger.kernel.org, linux-security-module@vger.kernel.org, selinux@vger.kernel.org, apparmor@lists.ubuntu.com, linux-nfs@vger.kernel.org, netdev@vger.kernel.org, fuse-devel@lists.linux.dev, linux-efi@vger.kernel.org, xen-devel@lists.xenproject.org, ocfs2-devel@lists.linux.dev, linux-s390@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-usb@vger.kernel.org, Amir Goldstein , linux-erofs@lists.ozlabs.org, linux-kselftest@vger.kernel.org Date: Fri, 13 Nov 2026 11:25:57 +0100 In-Reply-To: <20261111151202.GA11391@lst.de> References: <20261110-work-loop-pseudo-v1-0-4c998976c6c7@kernel.org> <20261110-work-loop-pseudo-v1-38-4c998976c6c7@kernel.org> <20261111151202.GA11391@lst.de> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.56.2-0+deb13u1 X-Archived-By: MIME-Version: 1.0 X-Rspamd-Queue-Id: 996EB140002 X-Rspamd-Server: rspam12 X-Stat-Signature: 9aknqjkosiaaktqtt7hcqnyut6fd7nq6 X-Rspam-User: X-Spam-Status: No, score=-3.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_PASS,SPF_PASS autolearn=no autolearn_force=no version=4.0.1 X-HE-Tag: 1794565561-764408 X-HE-Meta: U2FsdGVkX1+M8emqz4aU9LcpZ7LsPyWcmRUpRYUt7UCah7gwxHsbjUqf80TLeLFyhQBL4h44dJQpWy69Qr7wS0aXEcBwx2rwXdzvGeYT5rIs/YnGpnuqACPgIozwdetWiF6M6mQyFeeDveVL/2Daq1JXBIOElxHvKmjb3j4lT8vAwlmw7mpxyE7IqEsVZ14YRm/3IWSghkCAYlbLeB/vTtjooDVSPFcbvBR91uGhKem2ZB7uKwAIoCzpEV9qzm6Tn4PZQVjnyAO5JvrrshUMUj92AaiSpmxMgdKdlhR9AbWAhu7nUgXZXKhU2G/jleNa6qTRjTD73oEBY1vKf798TOSQcKiN7Ok8ATv+LqXHQdGrxWoUuYqY4/yYbnUAudeNLLKAZP6zGp85eyv8Q8IbDjtRYYxktT5EF4Mxmt/fkmpFl/Qb1/tng49y+qnbnNGSDioYlodm/zvR6xEAxhxBVD/560agqMkG1X4KWfQLUphaC/bX2iJLvktaQrbDMvoqZIuaRoXf4pnll/qSECzvhJiVXkTIRYX3IGOjJl6ZchMKv748i2Y44Qskfds5lEUngntcfVP/8sryZvp+aa5UgCHBxWkxCFw82gkbEEQIeIchNrMxlSQUxkQ1a8B9xCuUI8GjFm2/+k4dPyrArjhW+xTdmpAKp6Hj27quM5SlmH6Sdkaw6ZJbpEAc5clEXrk3Pe2FxK4LX7lWV+iMDDcKpCJxRCzB/y5vtdoi7QzC2bWRXuYK+auzBCbOdrRfK3DM2Jrj0u2kyVTHabrGzgv+7pAdZSzUgGXi+PEtywW0150zTWu9hkTQlGQNW172L1I2sYV8BxrfDYcnFL+L9I480n2hyhEk4Qa6jyTvUjJdccebbSJtCCRndB+Y6zmwBl05Q1rfCgQGSjyEX9nxcWen75HL+mzK8FWAO6QY05xiBIE8xJmf1C0+MsnJR3TMEkMx87kQB5mU8+KRCob/ELU zS8KUP7w yzm72Uiw55mt/oAmMGlsUIte0/uQhxPPRt/I6VgfNKdsQoG8kAWxB/DmSyfuAo7sxh55OiRteAxIQfqt6ke1A7hWBEejPbS14qWK4/FXazY1meVnARL5zC9cOJd71w+ZgPieYDghizm5ddBeCZ5x/CK0zh92WFWcY3NHzTd1/h6b+M5E7N2wjvZzq7xI373xIzDRw62tvlkjsirZaNSZNwzrd/awXxmM8zzb8RK/toDyFsDGNZIIScFjVyxoEC2JK6MJ9UrvIKhk5s4ZsywqCtEDzjTGkRhXXd11Mx328cGZ1TIE1fwPoNmsKKsfI2fn8gfoPHKDOKP1DdAD3dhSu1bu3ZYY3X2Lq7/CJGSqjkT6iHYh8Szl73WBDNyLDCOu4nunoSpEhXovdumZNh4Psp7PUUOlMsQPqbr2BRgS8XpRrWxvPFRg9mRQezzRZQVKTVst4HWjeNhx+/cw= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 Hi Christoph, On Wed, 2026-11-11 at 16:12 +0100, Christoph Hellwig wrote: > I've seen setups where people use fuse to mediate access to sysfs > sysfs in odd ways.=C2=A0 No idea if that's still around, but if so, this > patch will break it. Oh, that's painful. Do they use backing files for that? It's a relatively new feature in FUSE... Kind regards, Alex