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Wed, 27 May 2020 15:20:55 +0000 (UTC) MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Date: Wed, 27 May 2020 15:11:47 -0000 From: Christian Schoenebeck <1877688@bugs.launchpad.net> To: qemu-devel@nongnu.org X-Launchpad-Notification-Type: bug X-Launchpad-Bug: product=qemu; status=Fix Committed; importance=Undecided; assignee=qemu_oss@crudebyte.com; X-Launchpad-Bug-Tags: 9p virtfs X-Launchpad-Bug-Information-Type: Public X-Launchpad-Bug-Private: no X-Launchpad-Bug-Security-Vulnerability: no X-Launchpad-Bug-Commenters: c3bacd17 schoenebeck X-Launchpad-Bug-Reporter: A A (c3bacd17) X-Launchpad-Bug-Modifier: Christian Schoenebeck (schoenebeck) References: <158898272347.4759.14841085044555564691.malonedeb@chaenomeles.canonical.com> Message-Id: <159059230792.6063.17282780884756443499.malone@wampee.canonical.com> Subject: [Bug 1877688] Re: 9p virtfs device reports error when opening certain files 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="275d46a24253e557e4403d52832837e4bfa425b6"; Instance="production-secrets-lazr.conf" X-Launchpad-Hash: 8eb3fa1bc8f4bc97e1af1cd73fbb760563a09f1f Received-SPF: none client-ip=91.189.90.7; envelope-from=bounces@canonical.com; helo=indium.canonical.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/05/27 10:55:47 X-ACL-Warn: Detected OS = Linux 3.11 and newer [fuzzy] 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, URIBL_BLOCKED=0.001 autolearn=_AUTOLEARN 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 1877688 <1877688@bugs.launchpad.net> Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Fix is now committed on master as SHA-1 cf45183b718f02b1369e18c795dc51bc182= 1245d, which actually just reverted the mentioned commit that was leading t= o this broken behavior: https://github.com/qemu/qemu/commit/cf45183b718f02b1369e18c795dc51bc1821245d The original Xen transport bug that motivated that change, was now fixed di= fferently by handling that Xen issue solely on Xen transport driver side: https://github.com/qemu/qemu/commit/a4c4d462729466c4756bac8a0a8d77eb63b21ef7 ** Changed in: qemu Status: In Progress =3D> Fix Committed -- = You received this bug notification because you are a member of qemu- devel-ml, which is subscribed to QEMU. https://bugs.launchpad.net/bugs/1877688 Title: 9p virtfs device reports error when opening certain files Status in QEMU: Fix Committed Bug description: Reading certain files on a 9p mounted FS produces this error message: qemu-system-x86_64: VirtFS reply type 117 needs 12 bytes, buffer has 12, less than minimum After this error message is generated, further accesses to the 9p FS hangs whatever tries to access it. The Arch Linux guest system is otherwise usable. This happens with QEMU 5.0.0 and guest kernel version 5.6.11, hosted on an Arch Linux distro. I use the following command to launch QEMU: exec qemu-system-x86_64 -enable-kvm -display gtk -vga virtio -cpu host -m 4G -netdev tap,ifname=3Dvmtap0,id=3Dvn0,script=3Dno,downscript=3Dno -d= evice virtio-net-pci,netdev=3Dvn0 -kernel kernel.img -drive file=3Dfile.img,format=3Draw,if=3Dvirtio -virtfs local,path=3Dmnt,mount_tag=3Dhost0,security_model=3Dpassthrough,id=3Dhost0 -append "console=3DttyS0 root=3D/dev/vda rw" There's nothing relevant in the guest kernel logs as far as I'm aware of with loglevel set to 7. I tracked down the issue to readv() with a small buffer(<=3D12 bytes) and then a large buffer(>=3D 1024 bytes). A C program is provided to trigger this behavior. To manage notifications about this bug go to: https://bugs.launchpad.net/qemu/+bug/1877688/+subscriptions