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([2605:e000:100e:8c61:b0a2:2229:1cbe:53d2]) by smtp.gmail.com with ESMTPSA id u25sm7221103pfm.115.2020.07.01.21.30.24 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 01 Jul 2020 21:30:25 -0700 (PDT) To: Linus Torvalds Cc: "linux-kernel@vger.kernel.org" , io-uring From: Jens Axboe Subject: [GIT PULL] io_uring fixes for 5.8-rc4 Message-ID: Date: Wed, 1 Jul 2020 22:30:24 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.8.0 MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: io-uring-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org Hi Linus, One fix in here, for a regression in 5.7 where a task is waiting in the kernel for a condition, but that condition won't become true until task_work is run. The task_work can't be run exactly because the task is waiting in the kernel, so we'll never make any progress. One example of that is registering an eventfd and queueing io_uring work, and then the task goes and waits in eventfd read with the expectation that it'll get woken (and read an event) when the io_uring request completes. The io_uring request is finished through task_work, which won't get run while the task is looping in eventfd read. Please pull! The following changes since commit d60b5fbc1ce8210759b568da49d149b868e7c6d3: io_uring: fix current->mm NULL dereference on exit (2020-06-25 07:20:43 -0600) are available in the Git repository at: git://git.kernel.dk/linux-block.git tags/io_uring-5.8-2020-07-01 for you to fetch changes up to ce593a6c480a22acba08795be313c0c6d49dd35d: io_uring: use signal based task_work running (2020-06-30 12:39:05 -0600) ---------------------------------------------------------------- io_uring-5.8-2020-07-01 ---------------------------------------------------------------- Jens Axboe (1): io_uring: use signal based task_work running Oleg Nesterov (1): task_work: teach task_work_add() to do signal_wake_up() fs/io_uring.c | 32 ++++++++++++++++++++++++-------- include/linux/sched/jobctl.h | 4 +++- include/linux/task_work.h | 5 ++++- kernel/signal.c | 10 +++++++--- kernel/task_work.c | 16 ++++++++++++++-- 5 files changed, 52 insertions(+), 15 deletions(-) -- Jens Axboe