[Pkg-rust-maintainers] Bug#1109051: virtiofsd: Unable to share folders to qemu:///session VMs with virtiofsd: Connection refused to socket

[Gianpaolo]

Package: virtiofsd
Version: 1.13.0-5+b1
Severity: important
X-Debbugs-Cc: gianpaoloc at gmail.com

Dear Maintainer,
using virt-manager I created a Windows11 VM as a user (qemu:///session). Everything works fine (the VM can be launched and works) until I setup a shared folder using virtiofsd:

<filesystem type="mount" accessmode="passthrough">
  <driver type="virtiofs"/>
  <source dir="/tmp"/>
  <target dir="host_tmp"/>
  <address type="pci" domain="0x0000" bus="0x06" slot="0x00" function="0x0"/>
</filesystem>

Under this condition the VM does not start anymore, with the error reported below. Notice that, the exact same VM, with the same configuration and shared folder, works when created in the system channel (qemu:///system).

The error reported by virt-manager is:
Error starting domain: internal error: process exited while connecting to monitor: 2025-07-10T09:08:24.760511Z qemu-system-x86_64: -chardev socket,id=chr-vu-fs0,path=/home/user/.config/libvirt/qemu/lib/domain-1-win11/fs0-fs.sock: Failed to connect to '/home/user/.config/libvirt/qemu/lib/domain-1-win11/fs0-fs.sock': Connection refused

Traceback (most recent call last):
  File "/usr/share/virt-manager/virtManager/asyncjob.py", line 71, in cb_wrapper
    callback(asyncjob, *args, **kwargs)
    ~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/share/virt-manager/virtManager/asyncjob.py", line 107, in tmpcb
    callback(*args, **kwargs)
    ~~~~~~~~^^^^^^^^^^^^^^^^^
  File "/usr/share/virt-manager/virtManager/object/libvirtobject.py", line 57, in newfn
    ret = fn(self, *args, **kwargs)
  File "/usr/share/virt-manager/virtManager/object/domain.py", line 1384, in startup
    self._backend.create()
    ~~~~~~~~~~~~~~~~~~~~^^
  File "/usr/lib/python3/dist-packages/libvirt.py", line 1390, in create
    raise libvirtError('virDomainCreate() failed')
libvirt.libvirtError: internal error: process exited while connecting to monitor: 2025-07-10T09:08:24.760511Z qemu-system-x86_64: -chardev socket,id=chr-vu-fs0,path=/home/user/.config/libvirt/qemu/lib/domain-1-win11/fs0-fs.sock: Failed to connect to '/home/user/.config/libvirt/qemu/lib/domain-1-win11/fs0-fs.sock': Connection refused

Similar error is reported in journald.

The launching user ("user" in the bug report above) is in group libvirt.

Thanks
  G.

-- System Information:
Debian Release: 13.0
  APT prefers testing-security
  APT policy: (500, 'testing-security'), (500, 'stable-updates'), (500, 'stable-security'), (500, 'oldstable-updates'), (500, 'unstable'), (500, 'testing'), (500, 'stable'), (500, 'oldstable'), (1, 'experimental')
Architecture: amd64 (x86_64)
Foreign Architectures: i386

Kernel: Linux 6.12.35+deb13-amd64 (SMP w/16 CPU threads; PREEMPT)
Kernel taint flags: TAINT_PROPRIETARY_MODULE, TAINT_CPU_OUT_OF_SPEC, TAINT_USER, TAINT_OOT_MODULE, TAINT_UNSIGNED_MODULE
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8), LANGUAGE=en_US:en
Shell: /bin/sh linked to /usr/bin/dash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled

Versions of packages virtiofsd depends on:
ii  libc6        2.41-9
ii  libcap-ng0   0.8.5-4+b1
ii  libgcc-s1    14.2.0-19
ii  libseccomp2  2.6.0-2

virtiofsd recommends no packages.

virtiofsd suggests no packages.

-- no debconf information