[CentOS] ][SOLVED] suddenly X gives black screen with small clock cursor

[Fred Smith]

On Fri, Oct 11, 2013 at 02:06:19PM -0400, Fred Smith wrote:
> On Fri, Oct 11, 2013 at 09:41:08AM -0400, Fred Smith wrote:
> > On Fri, Oct 11, 2013 at 02:50:14AM -0700, John Doe wrote:
> > > From: Fred Smith <fredex at fcshome.stoneham.ma.us>
> > > 
> > > >  I rebooted a while ago (and in between the down and up, I installed Fedora
> > > >  20 Beta on a USB hard drive, making sure it wouldn't mess with my 
> > > > Centos  system). The install went fine, but afterwards, when I reboot Centos, it
> > > >  comes up with a black screen and a clock as the mouse cursor (small clock).
> > > > 
> > > >     chmod a+rw /dev/null
> > > >     chmod a+rw /dev/urandom
> > > >     chmod a+rw /dev/zero
> > > >     chmod a+rw /dev/full
> > > >     chmod a+rw /dev/random
> > > > 
> > > > Can anyone suggest an accurate way to have the system fix all the permissions
> > > > in /dev? some arcane options on rpm, perhaps?
> > > 
> > > Nothing at all in the logs...?
> > 
> > Nothing I can see in the logs looks particularly damning.
> > 
> > > Global check: rpm -qVa
> > running that right now, will post again if anything interesting turns up.
> > 
> > > Maybe check udev confs...?
> > I was thinking of that, but the amount I know aobut udev wouldn't cover
> > the head of a pin. Open to suggestions, though.
> 
> Looking in /lib/udev/rules.d/50-udev-default.rules I see:
> 
> KERNEL=="ptmx",			GROUP="tty", MODE="0666"
> KERNEL=="null|zero|full|random|urandom", MODE="0666"
> 
> so if I understand them right, /dev/ptmx, /dev/null, /dev/zero, /dev/full,
> /dev/random, and /dev/urandom should all come up as 'rw' for all users
> after a system boot, but they don't. I reboot and they all come up as
> 0644, crw-rw----.  grepping for "null" in /lib/udev finds only that
> single entry in all of the files, as does "ptmx".
> 
> So, I wonder if something is preventing this file from being run (which
> seems unlikely, given that it contains a ton of rules which would all
> be skipped). I note that /etc/udev/rules.d contains a rules file with
> exactly the same name (which sets up some firewire stuff) and wonder if
> that's a problem,... anyone know?

sigh. the problem, had this been a car, could have been diagnosed as:
"There's a loose nut behind the wheel." I.e., me. it's exactly due to 
the duplicate udev rules filenames, one in /etc/udev/rules.d and the
other in lib/udev/rules.d. Self-inflicted damage. PROBLEM SOLVED. 

-- 
---- Fred Smith -- fredex at fcshome.stoneham.ma.us -----------------------------
                      The eyes of the Lord are everywhere, 
                    keeping watch on the wicked and the good.
----------------------------- Proverbs 15:3 (niv) -----------------------------