Created attachment 416865 [details]
Randr configuration file causing hangs
Description of problem:
I am using RHEL6 on laptop in docking station with external monitor.
Today after opening of partially closed laptop (still in docking station, with monitor attached to docking station, not sleeping - being in screensaver and waiting for password) strange thing happened. Position of laptop-screen to monitor-screen swapped - from laptop left and monitor right to vice versa.
So I entered password to screensaver and click gnome-display-settings applet to change it back. There was some warning telling me there is a probem with monitor settings (I am sorry for not having screenshot). Anyway, I switched position back and - X server hanged.
After logging via ssh and doing reboot -f (shutdown -r now did not work), this hang repeatedly happens every time I log into Gnome with same user. With new user it does not happen.
I tracked the problem down to ~/.config/monitors.xml (and monitors.xml.backup).
Without these files, logging for this particular user works again. Putting these files back makes the problem appear again. I will attach these.
Also, there are such errors in messages:
kernel: INFO: task i915:152 blocked for more than 120 seconds.
kernel: INFO: task Xorg:2641 blocked for more than 120 seconds.
(see attachments for full error messages)
So it seems some situation caused gnome-display-settings to generate possibly invalid configuration, libgnomedesktop RRandr code tries to apply it and Xorg server hangs.
Version-Release number of selected component (if applicable):
Always on my desktop when using attached monitors.xml
Steps to Reproduce:
1. useradd -m testuser
2. put monitors.xml into /home/testuser/.config/ (owner testuser)
3. try to log in via gdm as this testuser
X server hangs, computer gets unusable locally.
Ssh access is possible, but Xorg cannot be killed and even shutdown -r does not work (reboot -f works).
No hangs! Perhaps a warning or sanitization if monitors.xml is really broken.
And if it is broken, it would be nice to find out why it was crippled by gnome-display-settings applet.
RandR code in libgnomedesktop is responsible for handling monitors.xml. It is nicely documented: http://live.gnome.org/RandR
Created attachment 416866 [details]
lspci -vv output
Created attachment 416869 [details]
Relevant part of /var/log/messages
Created attachment 416871 [details]
Unfortunately, I am not sure which log file is the one from hang - so I bundled all available.
of course using the randr apis shouldn't cause a hang and kernel backtraces.
This request was evaluated by Red Hat Product Management for inclusion in a Red
Hat Enterprise Linux major release. Product Management has requested further
review of this request by Red Hat Engineering, for potential inclusion in a Red
Hat Enterprise Linux Major release. This request is not yet committed for
Please try to reproduce with kernel-2.6.32-33.el6 or later.
I was not able to reproduce using kernel 2.6.32-33.el6.x86_64.
This should be fixed by the X -nr bug fixed in 2.6.32-33. marking as duplicate of that bug.
*** This bug has been marked as a duplicate of bug 577959 ***