After a recent Rawhide update, apologies I cannot be specific to a given day, on rebooting, the boot gets as far as showing the Xorg cursor and then does nothing more. GDM does not display. The virtual terminals work fine. Logging in I see gdm appears to be running, as is Xorg. Reviewing the log with journalctl I did see that GNOME Shell terminated with a SIGSEGV so I have reported this as a problem against GNOME Shell – though the only other evidence I have for accusing this package is that there are GNOME Shell Extension packages that cannot upgrade due to the wrong version of GNOME Shell being installed. It seems like there has been a problem upgrading GNOME Shell. At least three independent people seem to be having the same problem, hence this bug report. So whilst the kernel boot is fine, I have marked this urgent because GNOME does not start at all, making the system unusable as a graphical boot system.
I'm going to close this as a dupe of bug 1401886. Petr is working on debugging that, and I believe it's the same issue. *** This bug has been marked as a duplicate of bug 1401886 ***