[Bug 1187189] Re: Kernel crash and reboot when accessing video device

[Martin Pitt]

Discussed with Oliver on IRC. I reverted the /vendor/firmware and
/system/firmware lookup bits, but that was a no-op change after all as
lxc-android-cfg diverts the rules.

There is no need for diversion there, BTW: lxc-android-cfg could just
ship (or create in postinst) an empty
/etc/udev/rules.d/50-firmware.rules file which will override the file in
/lib/udev/rules.d (see /etc/udev/rules.d/README). So if you want to put
that into the image build process instead, or simplify the diversion,
you can do that, but otherwise the divert will work as well.

** Changed in: systemd (Ubuntu)
       Status: Incomplete => Invalid

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https://bugs.launchpad.net/bugs/1187189

Title:
  Kernel crash and reboot when accessing video device

Status in “linux-mako” package in Ubuntu:
  Confirmed
Status in “lxc-android-config” package in Ubuntu:
  Fix Released
Status in “systemd” package in Ubuntu:
  Invalid

Bug description:
  While working on the container flip, we noticed that starting udev and
  calling udevadm trigger would cause the device to reboot instantly.

  After some effort, we tracked this down to video4linux and
  specifically the 60-persistent-v4l rules file. Looking into it, we see
  it's calling v4l_id and that's what's causing the reboot.

  Here's some basic reproducing step for saucy post-container flip:
  root at android:/ # mv /lib/udev/rules.d/60-persistent-v4l.rules /root
  root at android:/ # start udev
  udev start/running, process 1016
  root at android:/ # start udevtrigger                                             
  udevtrigger stop/waiting
  root at android:/ # cat /dev/video38
  --- reboot ---

  It looks like any attempt to open the video device causes the panic
  and reboot.

  Unfortunately I don't have any way to get a console or any kernel
  debug information so all I can tell is that there's something very
  wrong going with that video device.

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