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Wed, 15 Jan 2025 12:31:12 -0800 (PST) Message-ID: Date: Wed, 15 Jan 2025 13:31:11 -0700 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2] io_uring/rsrc: Simplify buffer cloning by locking both rings To: Jann Horn , Pavel Begunkov Cc: io-uring@vger.kernel.org, linux-kernel@vger.kernel.org References: <20250115-uring-clone-refactor-v2-1-7289ba50776d@google.com> Content-Language: en-US From: Jens Axboe In-Reply-To: <20250115-uring-clone-refactor-v2-1-7289ba50776d@google.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 1/15/25 1:26 PM, Jann Horn wrote: > The locking in the buffer cloning code is somewhat complex because it goes > back and forth between locking the source ring and the destination ring. > > Make it easier to reason about by locking both rings at the same time. > To avoid ABBA deadlocks, lock the rings in ascending kernel address order, > just like in lock_two_nondirectories(). I'm going to let this one sit for review for a day or two, and since it depends changes slated for 6.13, I'll queue it up in a post-merge branch for 6.14 if all goes well. Thanks! -- Jens Axboe