[Octave-bug-tracker] [bug #53521] GUI freezes and requires SIGKILL upon large pasted input

[Adrian]

URL:
  <http://savannah.gnu.org/bugs/?53521>

                 Summary: GUI freezes and requires SIGKILL upon large pasted
input
                 Project: GNU Octave
            Submitted by: adaerr
            Submitted on: Fri 30 Mar 2018 10:09:01 AM UTC
                Category: GUI
                Severity: 3 - Normal
                Priority: 5 - Normal
              Item Group: Segfault, Bus Error, etc.
                  Status: None
             Assigned to: None
         Originator Name: 
        Originator Email: 
             Open/Closed: Open
         Discussion Lock: Any
                 Release: 4.2.2
        Operating System: GNU/Linux

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Details:

If I past large input (10k-20k characters) into the octave GUI, CPU usage goes
up for a few seconds and then drops to zero. No output is shown and the GUI
becomes completely unresponsive, including to Ctrl-C. It does not redraw its
window content either.

To reproduce:
1) Generate a large input, e.g.
for n in {1..10000} ; do
  echo "N=${n};" >>octavepastetest.txt 
done
2) Open that file in an editor, select 3500 lines or more and paste into
octave-gui

The exact quantity of input that makes the GUI freeze does not seem to be
reproducible. I observed freezes for as little as 340 pasted lines /
12000chars (though of a more complex script than the above example). With the
above test some 3500 lines / 27000 chars freeze the GUI reliably on my box,
while <2500 lines are processed without problem.

Once the GUI is frozen, sending the octave-gui process the TERM signal may
result in either of the following:
- no effect
- termination of both the octave and the octave-gui processes ("octave exited
with signal 6") if Ctrl-C had *not* been pressed; this seems to be the same
behaviour (and signal) as when a normally responsive GUI is terminated via
SIGTERM.
- GUI prints part of the pasted input, and becomes functional again (if Ctrl-C
had been pressed before sending the TERM signal).





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