Description of problem:
SELinux is preventing gnome-shell from using the 'signull' accesses on a process.

*****  Plugin catchall (100. confidence) suggests   **************************

If you believe that gnome-shell should be allowed signull access on processes labeled unconfined_dbusd_t by default.
Then you should report this as a bug.
You can generate a local policy module to allow this access.
Do
allow this access for now by executing:
# ausearch -c 'gnome-shell' --raw | audit2allow -M my-gnomeshell
# semodule -X 300 -i my-gnomeshell.pp

Additional Information:
Source Context                system_u:system_r:xdm_t:s0-s0:c0.c1023
Target Context                unconfined_u:unconfined_r:unconfined_dbusd_t:s0-s0
                              :c0.c1023
Target Objects                Unknown [ process ]
Source                        gnome-shell
Source Path                   gnome-shell
Port                          <Unknown>
Host                          (removed)
Source RPM Packages           
Target RPM Packages           
Policy RPM                    selinux-policy-3.13.1-224.fc25.noarch
Selinux Enabled               True
Policy Type                   targeted
Enforcing Mode                Enforcing
Host Name                     (removed)
Platform                      Linux (removed) 4.8.11-300.fc25.x86_64 #1 SMP Mon
                              Nov 28 18:24:51 UTC 2016 x86_64 x86_64
Alert Count                   2
First Seen                    2016-12-07 08:28:50 CET
Last Seen                     2016-12-07 08:28:50 CET
Local ID                      c11c441d-6008-4d84-aac0-6ae35a1ec730

Raw Audit Messages
type=AVC msg=audit(1481095730.711:244): avc:  denied  { signull } for  pid=1717 comm="ibus-daemon" scontext=system_u:system_r:xdm_t:s0-s0:c0.c1023 tcontext=unconfined_u:unconfined_r:unconfined_dbusd_t:s0-s0:c0.c1023 tclass=process permissive=0


Hash: gnome-shell,xdm_t,unconfined_dbusd_t,process,signull

Version-Release number of selected component:
selinux-policy-3.13.1-224.fc25.noarch

Additional info:
component:      selinux-policy
reporter:       libreport-2.9.3
hashmarkername: setroubleshoot
kernel:         4.13.12-300.fc27.x86_64
type:           libreport

Potential duplicate: bug 1440376