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=-3.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 76896C43460 for ; Tue, 20 Apr 2021 08:35:32 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id C6FAB60FE3 for ; Tue, 20 Apr 2021 08:35:31 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C6FAB60FE3 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=bugs.launchpad.net Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:48736 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lYlr0-0006qK-LG for qemu-devel@archiver.kernel.org; Tue, 20 Apr 2021 04:35:30 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:48278) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lYlit-0004nC-25 for qemu-devel@nongnu.org; Tue, 20 Apr 2021 04:27:07 -0400 Received: from indium.canonical.com ([91.189.90.7]:59000) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1lYlin-0002a6-Hv for qemu-devel@nongnu.org; Tue, 20 Apr 2021 04:27:06 -0400 Received: from loganberry.canonical.com ([91.189.90.37]) by indium.canonical.com with esmtp (Exim 4.86_2 #2 (Debian)) id 1lYlik-00028H-Mg for ; Tue, 20 Apr 2021 08:26:58 +0000 Received: from loganberry.canonical.com (localhost [127.0.0.1]) by loganberry.canonical.com (Postfix) with ESMTP id 587862E816D for ; Tue, 20 Apr 2021 08:26:57 +0000 (UTC) MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Date: Tue, 20 Apr 2021 08:04:48 -0000 From: Thomas Huth <1813045@bugs.launchpad.net> To: qemu-devel@nongnu.org X-Launchpad-Notification-Type: bug X-Launchpad-Bug: product=qemu; status=Incomplete; importance=Undecided; assignee=None; X-Launchpad-Bug-Information-Type: Public X-Launchpad-Bug-Private: no X-Launchpad-Bug-Security-Vulnerability: no X-Launchpad-Bug-Commenters: michele.schillaci th-huth X-Launchpad-Bug-Reporter: Michele Schillaci (michele.schillaci) X-Launchpad-Bug-Modifier: Thomas Huth (th-huth) References: <154826325670.29740.8985180444326228276.malonedeb@soybean.canonical.com> Message-Id: <161890588843.10588.14617999131761737402.malone@chaenomeles.canonical.com> Subject: [Bug 1813045] Re: qemu-ga fsfreeze crashes the kernel X-Launchpad-Message-Rationale: Subscriber (QEMU) @qemu-devel-ml X-Launchpad-Message-For: qemu-devel-ml Precedence: bulk X-Generated-By: Launchpad (canonical.com); Revision="8932ab84469600dc3d8b3344fb7135c702d5179e"; Instance="production" X-Launchpad-Hash: 9f2b0f0d8b057ccdcba5b75e104ffa03ba4ecdcb Received-SPF: none client-ip=91.189.90.7; envelope-from=bounces@canonical.com; helo=indium.canonical.com X-Spam_score_int: -65 X-Spam_score: -6.6 X-Spam_bar: ------ X-Spam_report: (-6.6 / 5.0 requ) BAYES_00=-1.9, HEADER_FROM_DIFFERENT_DOMAINS=0.249, RCVD_IN_DNSWL_HI=-5, RCVD_IN_MSPIKE_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_NONE=0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: Bug 1813045 <1813045@bugs.launchpad.net> Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" The QEMU project is currently considering to move its bug tracking to anoth= er system. For this we need to know which bugs are still valid and which co= uld be closed already. Thus we are setting older bugs to "Incomplete" now. If you still think this bug report here is valid, then please switch the st= ate back to "New" within the next 60 days, otherwise this report will be ma= rked as "Expired". Or mark it as "Fix Released" if the problem has been sol= ved with a newer version of QEMU already. Thank you and sorry for the incon= venience. ** Changed in: qemu Status: New =3D> Incomplete -- = You received this bug notification because you are a member of qemu- devel-ml, which is subscribed to QEMU. https://bugs.launchpad.net/bugs/1813045 Title: qemu-ga fsfreeze crashes the kernel Status in QEMU: Incomplete Bug description: We use mainly Cloudlinux, Debian and Centos. We experienced many crashes on our qemu instances based on Cloudlinux dur= ing a snapshot. The issue is not related to CloudLinux directly, but to Qemu agent, which= does not freeze the file system(s) correctly. What is actually happening: When VM backup is invoked, Qemu agent freezes the file systems, so no sin= gle change will be made during the backup. But Qemu agent does not respect = the loop* devices in freezing order (we have checked its sources), which le= ads to the next situation: = 1) freeze loopback fs ---> send async reqs to loopback thread 2) freeze main fs 3) loopback thread wakes up and trying to write data to the main fs, whic= h is still frozen, and this finally leads to the hung task and kernel crash= . = I believe this is the culprit: /dev/loop0 /tmp ext3 rw,nosuid,noexec,relatime,data=3Dordered 0 0 /dev/loop0 /var/tmp ext3 rw,nosuid,noexec,relatime,data=3Dordered 0 0 To manage notifications about this bug go to: https://bugs.launchpad.net/qemu/+bug/1813045/+subscriptions