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[2a02:3100:b2ac:9b01:21dd:e5b3:2a30:2e97]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-48e3ecd35c2sm24338968f8f.39.2026.10.27.13.45.51 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 27 Oct 2026 13:45:51 -0700 (PDT) Date: Tue, 27 Oct 2026 21:45:50 +0100 From: Karl Mehltretter To: Jens Axboe Cc: io-uring@vger.kernel.org, regressions@lists.linux.dev, linux-kernel@vger.kernel.org Subject: Re: [REGRESSION] io_uring: final close can hang on a stopped submitter Message-ID: References: <20261027043521.99446-1-kmehltretter@gmail.com> X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Tue, Oct 27, 2026 at 12:04:59PM +0100, Jens Axboe wrote: > > 3. A unmaps the ring but keeps its fd. B drops its fd and mappings, > > then stops itself with SIGSTOP. > > 4. After confirming that B is stopped, controller P tells A to close > > the final ring fd. > > 5. P resumes B after two seconds so the test can finish. > > > > B keeps both pipe ends open and remains alive until close returns. This > > excludes pipe HUP and process exit as completion sources. > > This is working as intended. With the change, close() waits for > requests still in flight, as otherwise they keep files pinned after > the ring is gone. If you SIGSTOP a task, then that task can't run > the required work to complete it. A fatal signal will still kill > it. > > Unsurprisingly, sending SIGSTOP to something may prevent it from > doing work... > Good point. This is not a real regression. Thanks, Karl