[Aptitude-devel] Bug#819840: aptitude: Segfaults if suspended and foregrounded on virtual linux console

[Axel Beckert]

Hi Manuel,

Manuel A. Fernandez Montecelo wrote:
> >aptitude segfaults under the following circumstances:
> >
> >1. Log in as root on a Linux virtual console, i.e. after pressing
> >  Ctrl-Alt-F1.
> >
> >2. Start aptitude in TUI mode, i.e. without any options or parameters.
> >
> >3. Press Ctrl-Z to suspend aptitude.
> >
> >4. Enter "fg" on the commandline and press Enter to bring aptitude back
> >  to the foreground.
> >
> >5. Segfault.
> >
> >This does not happen, if
> >
> >* if tried inside an xterm
> >* if just TERM is set to "linux", but the terminal is no virtual linux
> > console, i.e. "env TERM=linux aptitude" does not exhibit the issue.
> 
> What's "TERM" in the vt console?

linux

> Mine is "linux", and as you noted, it works fine. 

I didn't say that. I just said that in a non-virtual-console (i.e. an
xterm), "env TERM=linux aptitude" does not crash. I didn't say, that
TERM=linux in general prevents the crash. It's just not sufficient to
provoke the crash.

But if you don't get the crash on the vt console, I wonder what else
is needed to provoke the crash as I was able to reproduce it on two Sid
machines with different architectures out of the box.

Is there a chance that LC_CHAR is involved? That's usually set to
something with .UTF-8 at the end for me, either en_{GB,US,DK}.UTF-8 or
C.UTF-8.

> If I "unset TERM" or set it to the empty string, aptitude refuses to
> start ("Error opening terminal: unknown"). If I set it to "linux",
> "xterm" or "xterm-256color" it works fine. "vt100" works fine, but
> no colours.

Did you try these variants inside an terminal emulator under X or on a
Linux virtual console?

> In any case, I couldn't get it to crash by suspending and restoring.

Can you cross-check if you really had the same environment (vt
console)? It seems there may have been some misunderstanding wrt. just
setting $TERM vs the really used type of terminal. The latter matters,
the former is either irrelevant or at least not sufficient.

> None of the functions which name appears are from aptitude, cwidget or
> apt, unfortunately.

Oops. So this might be somewhere deeper down?

		Regards, Axel
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