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Thu, 24 Sep 2026 07:19:23 -0700 (PDT) Message-ID: Date: Thu, 24 Sep 2026 08:19:22 -0600 Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3 12/17] exec: cancel io_uring requests before de_thread() To: Christian Brauner , Oleg Nesterov , Chris Mason , linux-fsdevel@vger.kernel.org Cc: Alexander Viro , Jan Kara , NeilBrown , Ingo Molnar , Peter Zijlstra , linux-mm@kvack.org, io-uring@vger.kernel.org, stable@vger.kernel.org References: <20260921-work-coredump-fixes-v3-0-8e4adb1619e6@kernel.org> <20260921-work-coredump-fixes-v3-12-8e4adb1619e6@kernel.org> Content-Language: en-US From: Jens Axboe In-Reply-To: <20260921-work-coredump-fixes-v3-12-8e4adb1619e6@kernel.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 9/21/26 7:45 AM, Christian Brauner wrote: > begin_new_exec() cancels the exec'ing thread's io_uring requests after > de_thread() made it the only thread in the thread-group. Now > io_uring_task_cancel() runs task work after. If it runs a > create_worker_cb() item then a io-wq queued on the thread before the > exec creates a new io-wq worker thread. > > Said thread joins the thread-group which de_thread() just took down. The > io-iwq sticks around until it notices that its workqueue is dying. But > code after de_thread() relies on being single-threaded. > > Move io_uring_task_cancel() before de_thread() but behind the point of > no return. Any worker created during task work run from > io_uring_task_cancel() is just a sibling thread that de_thread() will > take down and reap. > > Once io_uring_task_cancel() returned the thread has neither a task > context nor a workqueue left so nothing can add a thread behind > de_thread()'s back anymore. Reviewed-by: Jens Axboe -- Jens Axboe