From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.5 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id AB059C4363D for ; Thu, 1 Oct 2020 03:03:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5708321D7D for ; Thu, 1 Oct 2020 03:03:24 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=kernel-dk.20150623.gappssmtp.com header.i=@kernel-dk.20150623.gappssmtp.com header.b="tIiRdS1e" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725799AbgJADDY (ORCPT ); Wed, 30 Sep 2020 23:03:24 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37016 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725372AbgJADDX (ORCPT ); Wed, 30 Sep 2020 23:03:23 -0400 Received: from mail-pj1-x1041.google.com (mail-pj1-x1041.google.com [IPv6:2607:f8b0:4864:20::1041]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6648DC061755 for ; Wed, 30 Sep 2020 20:03:22 -0700 (PDT) Received: by mail-pj1-x1041.google.com with SMTP id kk9so1079244pjb.2 for ; Wed, 30 Sep 2020 20:03:22 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20150623.gappssmtp.com; s=20150623; h=subject:to:references:from:message-id:date:user-agent:mime-version :in-reply-to:content-language:content-transfer-encoding; bh=MkpKYdGeIV3KJ3Wg+a4T20fK6l2XTaPtjSNc7YMEgjE=; b=tIiRdS1eQxWJA+2cevgTPbiwIVwaopZJwpT0ropg0Sn575Qw+o4f5BBkavjhnrxewH De4I9jTrX0tki8NolbHe3z4Xm2KvobLs0fIIDfQ+Yjnb01QtYFKUNYRiS7o+XHTwokn+ BT7TuD2EY+7SkXPlbQT7MtrHMga2kywmY1bRr5icsh9Yhl0nPe0grbsDGlsCbGM2Ii9T pGPNGgO/v+XPWs1rk4r/APyB+ilvxHmQwGLt2OJHAVybC7CcU6NXXdiNz51x11NN/9/y HT79CXaTOiLnZtT22IvHZv1qcH60vbsMBMi9PzD25/aIQGxGNCyn3+qIl8b+tLCj8mF1 luaA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=MkpKYdGeIV3KJ3Wg+a4T20fK6l2XTaPtjSNc7YMEgjE=; b=G0vq/LdK8Td9zyjgyUdE/F36vKh7mjSOPvK63dvRv6lUoLGJtN//IBLU8BHk+qa4Jm 9XpmX9+nkq1HvB2qW2qnzUq/lo7ivUgSbks5AsFUlun1k0r+N4LOLRlRmxar+f87aToP cY6x2n/BpPcdAARtF4FYs0Y6NmseuO45MeQWQ7REjrxTuXQiCWLzRlWX93lzCLg04Pxm 4ahuX3DKokkfVfQVK69kO4PANyhta95YuCYNWzZvTUDERVyr/kMxuUTz5axvAzRmQ5Lo gcu4+RJBgUcAKVjOnVvN3ds2BK+FSDCXXLzjH+N5kDbiVvK501AZPzJjCEKaEByFm0a6 OQYw== X-Gm-Message-State: AOAM533OUp4tbeY+hoMJ+PUG2CMgb2xBp0kvbKe7t201lGPGL+KS5pka NIUWgwVXhSe6m0RbmYKib3RsR6hIJBXG24dO X-Google-Smtp-Source: ABdhPJxIFQtAgS+jGmxD73kIQULJZlOXbhcJIvMMlvVWQMSpHZXhCJba9G5QSyL+921o2bn6w0dPGQ== X-Received: by 2002:a17:90a:aa90:: with SMTP id l16mr5104260pjq.0.1601521401486; Wed, 30 Sep 2020 20:03:21 -0700 (PDT) Received: from [192.168.1.134] ([66.219.217.173]) by smtp.gmail.com with ESMTPSA id 63sm3865485pfw.42.2020.09.30.20.03.20 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 30 Sep 2020 20:03:20 -0700 (PDT) Subject: Re: io_uring possibly the culprit for qemu hang (linux-5.4.y) To: Ju Hyung Park , io-uring@vger.kernel.org References: From: Jens Axboe Message-ID: <8de3b94a-042a-4b64-0458-e827ec5695d6@kernel.dk> Date: Wed, 30 Sep 2020 21:03:20 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org On 9/30/20 10:26 AM, Ju Hyung Park wrote: > Hi everyone. > > I have recently switched to a setup running QEMU 5.0(which supports > io_uring) for a Windows 10 guest on Linux v5.4.63. > The QEMU hosts /dev/nvme0n1p3 to the guest with virtio-blk with > discard/unmap enabled. > > I've been having a weird issue where the system would randomly hang > whenever I turn on or shutdown the guest. The host will stay up for a > bit and then just hang. No response on SSH, etc. Even ping doesn't > work. > > It's been hard to even get a log to debug the issue, but I've been > able to get a show-backtrace-all-active-cpus sysrq dmesg on the most > recent encounter with the issue and it's showing some io_uring > functions. > > Since I've been encountering the issue ever since I switched to QEMU > 5.0, I suspect io_uring may be the culprit to the issue. > > While I'd love to try out the mainline kernel, it's currently not > feasible at the moment as I have to stay in linux-5.4.y. Backporting > mainline's io_uring also seems to be a non-trivial job. > > Any tips would be appreciated. I can build my own kernel and I'm > willing to try out (backported) patches. I'll see if I can reproduce this, thanks for the report! -- Jens Axboe