Comment # 33 on bug 898882 from Oliver Neukum

(In reply to Volker Barth from comment #32)
> Either my system is messed up somehow or I'm overlooking something basic.
> When booting the debug kernel (3.16.7-21.1) I get stuck because I get no
> possibility to login. Removing "splash=silent" shows an (probably) endless
> repetition (somewhere around every 10 seconds) of "Failed to start Login
> Service". KDM doesn't start accordingly.
> 
> Trying the fail-safe version of the debug kernel leads to tons of messages
> being printed out about a buffer being overrun and messages being dropped
> (/dev/kmsg iirc, I didn't write it down). I cancelled this try but can
> repeat it if a longer waiting would lead to a usable system.
> 
> Booting kernel-desktop shows no strange behavior.
> 
> Any idea on what's happening and how to solve it?

No, it is a separate bug. Please file it.