From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pf1-f175.google.com (mail-pf1-f175.google.com [209.85.210.175]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 430E528E0 for ; Mon, 2 May 2022 13:59:49 +0000 (UTC) Received: by mail-pf1-f175.google.com with SMTP id a11so12369965pff.1 for ; Mon, 02 May 2022 06:59:49 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20210112.gappssmtp.com; s=20210112; h=message-id:date:mime-version:user-agent:subject:content-language:to :cc:references:from:in-reply-to:content-transfer-encoding; bh=hn6D/1mqsOpZCb0UXXalBcsMMDA5nsOG2XFxL4M3FKo=; b=OxSrCcWoV2/rXEc6h151zY/qeO1X7dtWA9CugimCewGit5D5A4IuMRCiGXyidVeV6l 3812vCWntOXN1sP5c48z5i5HoWOkTRvGONajtLg53LYaCjT/qd1vnBvrx8veSBXEYLnr 2wKLCEC1o9H++kbF8zEQp9qq9W337Wpsy44u7wWH1qRSzv6jNTM0NitUxFJevAdqy0c0 MyPslOJpkoFTmDeiARvhzcL9L/JvniGGm+wX3+8jWiz96rzO6ieki7yDV0KkqI7CATSK ulSDjmKVrsSRhiF/jQeGkcRJg/KYcNPYxOeUTg/DkeMEhRlH//OLk8qE5Nyjmy0WD8ro ngqQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:message-id:date:mime-version:user-agent:subject :content-language:to:cc:references:from:in-reply-to :content-transfer-encoding; bh=hn6D/1mqsOpZCb0UXXalBcsMMDA5nsOG2XFxL4M3FKo=; b=lliw4gCaSdmD2YGxwRpMcP81OZ4LU4cbBkQElt55jFIqxGZaUX7zffz8OGjhpL8xRO 94V2Yr3GdpBgwLd7vOVINT0e+J9uwaCHxFdqK4GIaC7pFJ3w4MJpvU+2PX5fCV/3m4fq Q6jNxsFrqxvkgq7eHWYAeRxmqkRWr/sJd124ObcR90LwSCqvW/s079mYzyQSr7ALu+GV jdNEdlj/qaENfrk6UX7N2J3WPjc+YoE9j70UXDB77ZuAyGEfqnLKWbNdw9UuN5UNzy4O uY2XApj0b9GI0BwsTfhotHUhdFDDjrJn8wpGG3a0K+iwOuYc8ILYLsM8mVpLyxLquFdF yCYw== X-Gm-Message-State: AOAM533hY3QM68X+CkfXd6NwC9u3Yykpi9ueKXpJ+T+ySXdrgGttHDaO T2nhcN//T86v/w8sO1XdSRrcJg== X-Google-Smtp-Source: ABdhPJxjx8WuzrEbZdVN+JUHo6GpAlTb6LBcVDFNfVOhcRgFUPo/c8ggfXBLEvDX2E8e3plRhWZwfA== X-Received: by 2002:a63:4a09:0:b0:382:597:3d0d with SMTP id x9-20020a634a09000000b0038205973d0dmr10027753pga.18.1651499989469; Mon, 02 May 2022 06:59:49 -0700 (PDT) Received: from [192.168.4.166] (cpe-72-132-29-68.dc.res.rr.com. [72.132.29.68]) by smtp.gmail.com with ESMTPSA id u4-20020aa78484000000b0050dc762813dsm2176532pfn.23.2022.05.02.06.59.48 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 02 May 2022 06:59:49 -0700 (PDT) Message-ID: Date: Mon, 2 May 2022 07:59:47 -0600 Precedence: bulk X-Mailing-List: regressions@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux aarch64; rv:91.0) Gecko/20100101 Thunderbird/91.8.1 Subject: Re: [REGRESSION] lxc-stop hang on 5.17.x kernels Content-Language: en-US To: Daniel Harding , Pavel Begunkov Cc: regressions@lists.linux.dev, io-uring@vger.kernel.org, linux-kernel@vger.kernel.org References: <7925e262-e0d4-6791-e43b-d37e9d693414@living180.net> <6ad38ecc-b2a9-f0e9-f7c7-f312a2763f97@kernel.dk> From: Jens Axboe In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 5/2/22 7:36 AM, Daniel Harding wrote: > On 5/2/22 16:26, Jens Axboe wrote: >> On 5/2/22 7:17 AM, Daniel Harding wrote: >>> I use lxc-4.0.12 on Gentoo, built with io-uring support >>> (--enable-liburing), targeting liburing-2.1. My kernel config is a >>> very lightly modified version of Fedora's generic kernel config. After >>> moving from the 5.16.x series to the 5.17.x kernel series, I started >>> noticed frequent hangs in lxc-stop. It doesn't happen 100% of the >>> time, but definitely more than 50% of the time. Bisecting narrowed >>> down the issue to commit aa43477b040251f451db0d844073ac00a8ab66ee: >>> io_uring: poll rework. Testing indicates the problem is still present >>> in 5.18-rc5. Unfortunately I do not have the expertise with the >>> codebases of either lxc or io-uring to try to debug the problem >>> further on my own, but I can easily apply patches to any of the >>> involved components (lxc, liburing, kernel) and rebuild for testing or >>> validation. I am also happy to provide any further information that >>> would be helpful with reproducing or debugging the problem. >> Do you have a recipe to reproduce the hang? That would make it >> significantly easier to figure out. > > I can reproduce it with just the following: > > sudo lxc-create --n lxc-test --template download --bdev dir --dir /var/lib/lxc/lxc-test/rootfs -- -d ubuntu -r bionic -a amd64 > sudo lxc-start -n lxc-test > sudo lxc-stop -n lxc-test > > The lxc-stop command never exits and the container continues running. > If that isn't sufficient to reproduce, please let me know. Thanks, that's useful! I'm at a conference this week and hence have limited amount of time to debug, hopefully Pavel has time to take a look at this. -- Jens Axboe