Bug#771545: Possible cause

[nemo Inis <nemoinis@hotmail.com>]

I just hit this (with reportbug 7.5.0).

I had started reportbug from a terminal inside my XFCE session, and after the GUI froze, I
found this on the terminal:

Use sudo to read the kernel log?

I replied "y", and sudo prompted me for my password. After giving it, reportbug worked normally.

So I think the issue is that reportbug's GUI is doing I/O on its controlling terminal, and sits
there waiting for a reply that never comes (because the user is looking at the GUI).