terminal freezes occationally

[Alan Mead]

I am using Konsole 1.2.3 on FC1 (KDE 3.1.4-4).  I run time consuming
numerical programs on this box and on occation, I find that the
terminal session has frozen.  The window itself (e.g., the menu)
still seems to act normally but nothing I do will make the session
echo commands or produce any screen output.  The session seems
frozen.  I have to exit and start a new session.

This only happens when I leave the window sit idle for a long time
(hours or days; as when I'm waiting for a long running foreground
process run).

Any ideas?

-Alan

[netmask]

> I am using Konsole 1.2.3 on FC1 (KDE 3.1.4-4).  I run time consuming
> numerical programs on this box and on occation, I find that the
> terminal session has frozen.  The window itself (e.g., the menu)
> still seems to act normally but nothing I do will make the session
> echo commands or produce any screen output.  The session seems
> frozen.  I have to exit and start a new session.
>
> This only happens when I leave the window sit idle for a long time
> (hours or days; as when I'm waiting for a long running foreground
> process run).
>
> Any ideas?

None off the top of my head, but when it does it.. I'd launch another console, 
find the pid of the one that is locked up (ps auxww|grep -i konsole)

and do an strace -p $pid   (where $pid is the process Id you got from the the 
ps command, second column)

Look at the strace output and see if it gives you anything worth while..

(Sorry if you already knew all of these commands and syntaxes.. adding in 
extra info tends to cut down on list "conversations")

[Alan Mead]

--- netmask  wrote:
> > I am using Konsole 1.2.3 on FC1 (KDE 3.1.4-4).  I run time

[...]
> > terminal session has frozen.  The window itself (e.g., the menu)
> > still seems to act normally but nothing I do will make the
>
> session
> > echo commands or produce any screen output.  The session seems
> > frozen.  I have to exit and start a new session.
> None off the top of my head, but when it does it.. I'd launch
> another console, 
> find the pid of the one that is locked up (ps auxww|grep -i
> konsole)
>
> and do an strace -p $pid   (where $pid is the process Id you got
> from the the 
> ps command, second column)

Hmm.. sounds interesting...

I see a Konsole process and a bash process.  When I strace the
Konsole process I get a series of things... I don't know what I'm
doing or what they mean... 'ioctl (3, FIONREAD, [Y])' appears a lot
with Y=0 or 32... anyway, it's responsive.

OTOH, when I 'strace -p' the frozen bash process, I get:

Process XXXX attached - interrupt to quit
ioctl(0, TCSETSW
(at this point I try hitting return a few times, nothing)
(I hit control-C)
<unfinished ...>
Process XXXX detached

Any idea what this means?

-Alan

[netmask]

> Hmm.. sounds interesting...
>
> I see a Konsole process and a bash process.  When I strace the
> Konsole process I get a series of things... I don't know what I'm
> doing or what they mean... 'ioctl (3, FIONREAD, [Y])' appears a lot
> with Y=0 or 32... anyway, it's responsive.

That's pretty normal behavior..  The 32 is telling you how long that line is, 
if you did 'strace -s 200 -p $pid', it would be a lot more noisy and not 
truncate so small.
> OTOH, when I 'strace -p' the frozen bash process, I get:
>
> Process XXXX attached - interrupt to quit
> ioctl(0, TCSETSW

The ioctl function manipulates the underlying device parameters of special 
files. (from man)

It looks like it is apparently waiting for something to happen. If your shell 
was at prompt, waiting for more input.. typically you would see that read:

read(0,

and nothing more..

The TCSETSW portion, is "Allow the output buffer to drain, and set the current 
serial port settings."
> (at this point I try hitting return a few times, nothing)
> (I hit control-C)
> <unfinished ...>
> Process XXXX detached
>
> Any idea what this means?

The detached message just means that you've successfully let go of the process 
with strace.

--

I'm not really sure based on that, what the issue is. Perhaps someone else 
with more knowledge of the gui behaviors (I stick to console only really), and 
that knows the innards of ioctl() could shed some light on it.

[Tom Mitchell]

On Sun, Oct 31, 2004 at 11:09:41PM -0800, netmask wrote:
> > Hmm.. sounds interesting...
> >
> > I see a Konsole process and a bash process.  When I strace the
> > Konsole process I get a series of things... I don't know what I'm
> > doing or what they mean... 'ioctl (3, FIONREAD, [Y])' appears a lot
> > with Y=0 or 32... anyway, it's responsive.
>
> That's pretty normal behavior..  The 32 is telling you how long that line 
> is, if you did 'strace -s 200 -p $pid', it would be a lot more noisy and 
> not truncate so small.
> > OTOH, when I 'strace -p' the frozen bash process, I get:
> >
> > Process XXXX attached - interrupt to quit
> > ioctl(0, TCSETSW
>
> The ioctl function manipulates the underlying device parameters of special 
> files. (from man)
>
> It looks like it is apparently waiting for something to happen.

It might be valuable to run the application under "screen".
Screen will keep a pseudo terminal alive even if the current terminal
session is trashed.

Try
    screen
    vi /tmp/watchme

Kill the terminal session (click on the X in the upper right)

Start a new terminal session

screen -r

You might also use the gnome-terminal   Menubar and reset the 
terminal.

You might also keep track of the tty then see what the tty values
are over time.
    
 stty -a < /dev/pts/3