[CentOS] Hung kernel task on CentOS 7.2, fprintd and libvirtd

[Gordon Messmer]

On 02/26/2016 05:17 PM, Warren Young wrote:
> I tracked this down with strace.  The 25 seconds above is the timeout value passed to poll(2); that timeout is hit while sudo (via PAM) is trying to talk to dbus, since apparently fprintd communicates via dbus.

If you can still replicate the problem, it might be instructive to use 
"dbus-monitor" to find out what is (and isn't) happening during 
authentication.