Description of problem:
SELinux is preventing sosreport from 'associate' accesses on the filesystem mdstat.

*****  Plugin associate (99.5 confidence) suggests   *************************

If you want to change the label of mdstat to proc_mdstat_t, you are not allowed to since it is not a valid file type.
Then you must pick a valid file label.
Do
select a valid file type.  List valid file labels by executing: 
# seinfo -afile_type -x

*****  Plugin catchall (1.49 confidence) suggests   **************************

If you believe that sosreport should be allowed associate access on the mdstat filesystem 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 'sosreport' --raw | audit2allow -M my-sosreport
# semodule -X 300 -i my-sosreport.pp

Additional Information:
Source Context                system_u:object_r:proc_mdstat_t:s0
Target Context                system_u:object_r:fs_t:s0
Target Objects                mdstat [ filesystem ]
Source                        sosreport
Source Path                   sosreport
Port                          <Unknown>
Host                          (removed)
Source RPM Packages           
Target RPM Packages           
Policy RPM                    <Unknown>
Selinux Enabled               True
Policy Type                   targeted
Enforcing Mode                Enforcing
Host Name                     (removed)
Platform                      Linux (removed) 4.11.11-300.fc26.x86_64 #1 SMP Mon
                              Jul 17 16:32:11 UTC 2017 x86_64 x86_64
Alert Count                   1
First Seen                    2017-09-05 16:17:07 EDT
Last Seen                     2017-09-05 16:17:07 EDT
Local ID                      9f0a4b55-8473-4db4-b0b9-6f6a366348a4

Raw Audit Messages
type=AVC msg=audit(1504642627.432:23995): avc:  denied  { associate } for  pid=13097 comm="sosreport" name="mdstat" dev="dm-12" ino=404998 scontext=system_u:object_r:proc_mdstat_t:s0 tcontext=system_u:object_r:fs_t:s0 tclass=filesystem permissive=0


Hash: sosreport,proc_mdstat_t,fs_t,filesystem,associate


Additional info:
component:      selinux-policy
reporter:       libreport-2.9.3
hashmarkername: setroubleshoot
kernel:         4.15.6-300.fc27.x86_64
type:           libreport