From: Christian Schoenebeck <1877688@bugs.launchpad.net>
To: qemu-devel@nongnu.org
Subject: [Bug 1877688] Re: 9p virtfs device reports error when opening certain files
Date: Wed, 27 May 2020 15:11:47 -0000 [thread overview]
Message-ID: <159059230792.6063.17282780884756443499.malone@wampee.canonical.com> (raw)
In-Reply-To: 158898272347.4759.14841085044555564691.malonedeb@chaenomeles.canonical.com
Fix is now committed on master as SHA-1 cf45183b718f02b1369e18c795dc51bc1821245d, which actually just reverted the mentioned commit that was leading to this broken behavior:
https://github.com/qemu/qemu/commit/cf45183b718f02b1369e18c795dc51bc1821245d
The original Xen transport bug that motivated that change, was now fixed differently by handling that Xen issue solely on Xen transport driver side:
https://github.com/qemu/qemu/commit/a4c4d462729466c4756bac8a0a8d77eb63b21ef7
** Changed in: qemu
Status: In Progress => Fix Committed
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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=vmtap0,id=vn0,script=no,downscript=no -device
virtio-net-pci,netdev=vn0 -kernel kernel.img -drive
file=file.img,format=raw,if=virtio -virtfs
local,path=mnt,mount_tag=host0,security_model=passthrough,id=host0
-append "console=ttyS0 root=/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(<=12 bytes)
and then a large buffer(>= 1024 bytes). A C program is provided to
trigger this behavior.
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next prev parent reply other threads:[~2020-05-27 15:22 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-09 0:05 [Bug 1877688] [NEW] 9p virtfs device reports error when opening certain files A A
2020-05-09 0:27 ` [Bug 1877688] " A A
2020-05-09 1:42 ` A A
2020-05-09 14:39 ` Christian Schoenebeck
2020-05-09 16:56 ` Christian Schoenebeck
2020-05-09 19:13 ` A A
2020-05-27 15:11 ` Christian Schoenebeck [this message]
2020-08-15 11:36 ` Christian Schoenebeck
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