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Sun, 04 Oct 2026 03:51:26 -0700 (PDT) From: Anshuman To: kees@kernel.org Cc: Frank.Li@kernel.org, James.Bottomley@HansenPartnership.com, airlied@gmail.com, akpm@linux-foundation.org, andriy.shevchenko@linux.intel.com, anton.ivanov@cambridgegreys.com, apparmor@lists.ubuntu.com, atomlin@atomlin.com, benjamin.berg@intel.com, bhelgaas@google.com, bp@alien8.de, bvanassche@acm.org, corey@minyard.net, da.gomez@kernel.org, daniel.lezcano@kernel.org, dave.hansen@linux.intel.com, david.e.box@linux.intel.com, dmaengine@vger.kernel.org, dri-devel@lists.freedesktop.org, dvyukov@google.com, elver@google.com, eperezma@redhat.com, georgia.garcia@canonical.com, glider@google.com, gor@linux.ibm.com, gregkh@linuxfoundation.org, hansg@kernel.org, hare@suse.de, hca@linux.ibm.com, hpa@zytor.com, ilpo.jarvinen@linux.intel.com, intel-gfx@lists.freedesktop.org, jani.nikula@linux.intel.com, jasowang@redhat.com, jbaron@akamai.com, jgg@ziepe.ca, jim.cromie@gmail.com, jirislaby@kernel.org, jmorris@namei.org, johannes@sipsolutions.net, john.johansen@canonical.com, joonas.lahtinen@linux.intel.com, kasan-dev@googlegroups.com, kvm@vger.kernel.org, laurent.pinchart@ideasonboard.com, lenb@kernel.org, leon@kernel.org, linux-acpi@vger.kernel.org, linux-arch@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-hardening@vger.kernel.org, linux-kernel@vger.kernel.org, linux-media@vger.kernel.org, linux-mm@kvack.org, linux-modules@vger.kernel.org, linux-pci@vger.kernel.org, linux-pm@vger.kernel.org, linux-rdma@vger.kernel.org, linux-scsi@vger.kernel.org, linux-security-module@vger.kernel.org, linux-serial@vger.kernel.org, linux-um@lists.infradead.org, linux-usb@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, lukasz.luba@arm.com, macro@orcam.me.uk, martin.petersen@oracle.com, mcgrof@kernel.org, mchehab@kernel.org, mingo@redhat.com, mst@redhat.com, netdev@vger.kernel.org, openipmi-developer@lists.sourceforge.net, paul@paul-moore.com, pbonzini@redhat.com, pengpeng@iscas.ac.cn, peterz@infradead.org, petr.pavlu@suse.com, qemu-devel@nongnu.org, rafael@kernel.org, richard@nod.at, rodrigo.vivi@intel.com, rui.zhang@intel.com, samitolvanen@google.com, seanjc@google.com, serge@hallyn.com, simona@ffwll.ch, somlo@cmu.edu, srinivas.pandruvada@linux.intel.com, stable@vger.kernel.org, stern@rowland.harvard.edu, tglx@kernel.org, tiwei.btw@antgroup.com, tursulin@ursulin.net, usb-storage@lists.one-eyed-alien.net, virtualization@lists.linux.dev, vkoul@kernel.org, x86@kernel.org, xuanzhuo@linux.alibaba.com Subject: Re: [PATCH 01/11] params: bound array element output to the caller's page buffer Date: Sun, 4 Oct 2026 16:17:41 +0530 Message-ID: <20261004104741.51238-1-anshumantewari123@gmail.com> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260521133326.2465264-1-kees@kernel.org> References: <20260521133326.2465264-1-kees@kernel.org> Precedence: bulk X-Mailing-List: linux-arch@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit On Thu, May 21, 2026 at 06:33:14AM -0700, Kees Cook wrote: > ret = min(ret, (int)(PAGE_SIZE - 1 - off)); > if (!ret) > break; One question about the truncation behavior here: when an element does not fully fit in the remaining buffer, this min() can cause only part of that element to be copied. For example, if the remaining space is 4 bytes and the next element produces "123456789\n", the resulting output could contain only "1234". This leaves the reader with no way to distinguish a genuinely short value from one that was truncated due to the PAGE_SIZE limit, while the array otherwise still looks like a normal comma-separated list. Is this partial-element truncation intentional for this patch, or is the expectation that it gets handled as part of the later seq_buf conversion? Would it be preferable to avoid copying an element unless it fits completely, and leave the larger-buffer case to be addressed later in the series?