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From: A A <1877688@bugs.launchpad.net>
To: qemu-devel@nongnu.org
Subject: [Bug 1877688] Re: 9p virtfs device reports error when opening certain files
Date: Sat, 09 May 2020 00:27:21 -0000	[thread overview]
Message-ID: <158898404210.10870.1156667153961277357.launchpad@wampee.canonical.com> (raw)
In-Reply-To: 158898272347.4759.14841085044555564691.malonedeb@chaenomeles.canonical.com

** Description changed:

  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.
+ 
+ Aha, I found the cursed file. See this strace log:
+ 
+ openat(AT_FDCWD, "/home/user/.local/share/nvim/shada/main.shada", O_RDONLY|O_CLOEXEC) = 25
+ mmap(NULL, 880640, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f3ab8427000
+ mmap(NULL, 880640, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f3ab8350000
+ mmap(NULL, 880640, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f3ab8279000
+ mmap(NULL, 880640, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f3ab81a2000
+ mmap(NULL, 880640, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f3ab80cb000
+ readv(25,

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https://bugs.launchpad.net/bugs/1877688

Title:
  9p virtfs device reports error when opening certain files

Status in QEMU:
  New

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.

  Aha, I found the cursed file. See this strace log:

  openat(AT_FDCWD, "/home/user/.local/share/nvim/shada/main.shada", O_RDONLY|O_CLOEXEC) = 25
  mmap(NULL, 880640, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f3ab8427000
  mmap(NULL, 880640, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f3ab8350000
  mmap(NULL, 880640, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f3ab8279000
  mmap(NULL, 880640, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f3ab81a2000
  mmap(NULL, 880640, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f3ab80cb000
  readv(25,

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  reply	other threads:[~2020-05-09  0:36 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 ` A A [this message]
2020-05-09  1:42 ` [Bug 1877688] " 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
2020-08-15 11:36 ` Christian Schoenebeck

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