Hi,
since we have upgraded to CentOS 7.5 (from CentOS 7.4), we experience frequent, but not reproducible, freezes of various applications: Thunderbird, Firefox, LibreOffice. Usually the application process keeps running with PPID 1 w/o being killable (not even with SIGKILL). Freezes of Thunderbird are usually followed by Firefox crashing a few minutes later. The only possible solution we found is a complete workstation reboot :-(.
Other problems are that many Gnome extensions are not working any more and also cannot be installed from extensions.gnome.org any more and logging in via gdm (LDAP, homedirectories on NFS share) is considerably slower than with 7.4.
I don't know if these issues are related, if they are symptoms of a more global problem and I am at a loss on how to debug them, as they appear from time to time but not not reproducibly..
Any hints or reports of own experiences are highly appreciated.
Cheers frank