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Fri, 05 Dec 2025 08:51:51 -0800 (PST) Message-ID: <27273a89-d4bb-4b64-9fa3-5edc3ff493dd@kernel.dk> Date: Fri, 5 Dec 2025 09:51:51 -0700 Precedence: bulk X-Mailing-List: io-uring@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v1] io_uring/kbuf: use WRITE_ONCE() for userspace-shared buffer ring fields To: Joanne Koong Cc: csander@purestorage.com, io-uring@vger.kernel.org References: <20251204235450.1219662-1-joannelkoong@gmail.com> Content-Language: en-US From: Jens Axboe In-Reply-To: <20251204235450.1219662-1-joannelkoong@gmail.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 12/4/25 4:54 PM, Joanne Koong wrote: > buf->addr and buf->len reside in memory shared with userspace. They > should be written with WRITE_ONCE() to guarantee atomic stores and > prevent tearing or other unsafe compiler optimizations. It's not a real concern, but I think we should still do it purely for documentation purposes. But because of that, I think we should drop: > Fixes: ae98dbf43d75 ("io_uring/kbuf: add support for incremental buffer consumption") to save me the trouble of ensuring older stable kernels get this applied. -- Jens Axboe