It's a 'console switch freeze', whenever there is heavy activity on the
text console, _and_ fast switching between consoles is done. The system is
up and no harm is done to anything (so it's not random corruption), but
the console cannot be switched away. [switchvt has no effect, nothing
helps, only a reboot]. I have no idea what this is, but i'm pretty sure it
first emerged when those big 2.1.3* console changes were added, (the
no-console support patch and other patches).
i can investigate further if the bug is only reproducible on my system ;)
The only nonstandard thing is that i'm using 10 text consoles, otherwise
it's a pretty plain console setup. [no SVGATextMode, no extra fonts,
nothing]
-- mingo