Re: long lasting TTY bug, still present in 2.1.48 pre2

Theodore Y. Ts'o (tytso@MIT.EDU)
Mon, 4 Aug 1997 15:05:26 -0400

Date: Sun, 3 Aug 1997 19:55:16 +0200 (MET DST)
From: Ingo Molnar <>

there is a reproducible TTY/console bug that was reported to linux-kernel
a few weeks ago, and i have seen it several times in a pre2 2.1.48 system,
so i guess it's not fixed yet.

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,

When you say "fast console switch", you just mean hitting Alt-F1,
Alt-F2, etc. very quickly, right?

I tried setting up in one window "while /bin/true; do; cat /etc/termcap;done",
and in another window, /usr/games/rain, and in a third window I simply
left idle. I then tried switching between these three windows very
quickly, and I couldn't reproduce it.

Can you send in a procedure which reasonably reliably reproduces the

Many thanks,

- Ted