How to crash Python in 1 easy step (python 2.2.2)

Discussion in 'Python' started by Paul Miller, Jul 13, 2003.

  1. Paul Miller

    Paul Miller Guest

    I'm not sure if this is a python bug or a bug in an associated
    library, and I'm not even sure how to correctly report it, but here is
    Anytime python is accepting keyboard input, whether it's with
    raw_input, or sitting on the command line waiting for the user to type
    code, you can crash python by holding ctrl+shift and then pressing
    enter.

    This is on a RedHat 9.0 system running on an Athlon 600. Basically
    everything about the system is standard except for what's been updated
    by RedHat itself. If anyone who has the time and ability to track
    down this bug needs more information, please email me.
    Paul Miller, Jul 13, 2003
    #1
    1. Advertising

  2. Paul Miller wrote:

    > I'm not sure if this is a python bug or a bug in an associated
    > library, and I'm not even sure how to correctly report it, but here is
    > Anytime python is accepting keyboard input, whether it's with
    > raw_input, or sitting on the command line waiting for the user to type
    > code, you can crash python by holding ctrl+shift and then pressing
    > enter.
    >
    > This is on a RedHat 9.0 system running on an Athlon 600. Basically
    > everything about the system is standard except for what's been updated
    > by RedHat itself. If anyone who has the time and ability to track
    > down this bug needs more information, please email me.


    I doubt it is a problem in Python, it works nicely on both my
    windows and my linux machines (python 2.2.3).

    Just a gut feeling: reinstall/upgrade your readline library.....

    --Irmen
    Irmen de Jong, Jul 13, 2003
    #2
    1. Advertising

  3. Paul Miller

    Jeff Epler Guest

    On Sun, Jul 13, 2003 at 10:44:41AM -0700, Paul Miller wrote:
    > I'm not sure if this is a python bug or a bug in an associated
    > library, and I'm not even sure how to correctly report it, but here is


    Doesn't happen here. What terminal (xterm, kterm, gnome-terminal,
    console?) and what LANG is set in your environment?

    If you run 'od -c' at the shell, then hit ctrl-shift-enter then ctrl-d,
    what does it show? I'd expect to see something very much like this:
    $ od -c

    0000000 \n
    0000001
    that is, even with the modifier keys, the program only sees a normal
    newline character.

    What happens if you type ctrl-shift-enter to another readline-linked
    program (for instance 'bc', an infix calculator)? Do you get the same
    crash?

    Does the behavior change if you run 'cat | python' and then press
    ctrl-shift-enter? This will avoid importing readline (and another
    side-effect is to suppress the normal ">>>" prompt of the interative
    interpreter)

    Jeff
    Jeff Epler, Jul 13, 2003
    #3
  4. Paul Miller wrote:
    > I'm not sure if this is a python bug or a bug in an associated
    > library, and I'm not even sure how to correctly report it, but here is
    > Anytime python is accepting keyboard input, whether it's with
    > raw_input, or sitting on the command line waiting for the user to type
    > code, you can crash python by holding ctrl+shift and then pressing
    > enter.
    >
    > This is on a RedHat 9.0 system running on an Athlon 600. Basically
    > everything about the system is standard except for what's been updated
    > by RedHat itself. If anyone who has the time and ability to track
    > down this bug needs more information, please email me.


    No problem here with Python 2.2.x
    (where x = cantRememberAndToLazyToCheckButThinkIts1)

    Bruno
    Bruno Desthuilliers, Jul 13, 2003
    #4
  5. Paul Miller

    Cliff Wells Guest

    On Sun, 2003-07-13 at 10:44, Paul Miller wrote:
    > I'm not sure if this is a python bug or a bug in an associated
    > library, and I'm not even sure how to correctly report it, but here is
    > Anytime python is accepting keyboard input, whether it's with
    > raw_input, or sitting on the command line waiting for the user to type
    > code, you can crash python by holding ctrl+shift and then pressing
    > enter.
    >
    > This is on a RedHat 9.0 system running on an Athlon 600.


    Redhat 9, Athlon XP 1700+. Python 2.2.2-26, readline 4.3-5

    Not a problem.

    Regards,
    Cliff

    --
    There's no light at the end of it all, let's all sit down and cry
    -This Mortal Coil
    Cliff Wells, Jul 14, 2003
    #5
  6. Paul Miller

    Ben Finney Guest

    On 13 Jul 2003 10:44:41 -0700, Paul Miller wrote:
    > Anytime python is accepting keyboard input, whether it's with
    > raw_input, or sitting on the command line waiting for the user to type
    > code, you can crash python by holding ctrl+shift and then pressing
    > enter.


    Is this in an xterm, in some other terminal emulator, in a console
    session? I'm guessing you'll see different behaviour if you try all
    three of those, which will help narrow down the problem.

    Not that a segfault (assuming that's what you mean by "crash") isn't a
    bug -- any event that doesn't make the system hardware unreliable should
    be handled without a segfault.

    --
    \ "One time a cop pulled me over for running a stop sign. He |
    `\ said, 'Didn't you see the stop sign?' I said, 'Yeah, but I |
    _o__) don't believe everything I read.'" -- Steven Wright |
    http://bignose.squidly.org/ 9CFE12B0 791A4267 887F520C B7AC2E51 BD41714B
    Ben Finney, Jul 14, 2003
    #6
  7. (Paul Miller) wrote in message news:<>...
    > I'm not sure if this is a python bug or a bug in an associated
    > library, and I'm not even sure how to correctly report it, but here is
    > Anytime python is accepting keyboard input, whether it's with
    > raw_input, or sitting on the command line waiting for the user to type
    > code, you can crash python by holding ctrl+shift and then pressing
    > enter.
    >
    > This is on a RedHat 9.0 system running on an Athlon 600. Basically
    > everything about the system is standard except for what's been updated
    > by RedHat itself. If anyone who has the time and ability to track
    > down this bug needs more information, please email me.


    I'm seeing the same effect on RH9, using KDE's "konsole" terminal
    emulator.
    When pressing Ctrl-Shift-Enter, it actually sends the ^[OM characters
    (Escape, O, M).
    Manually sending the key sequence Esc-O-something also crashes Python.

    Why this happens is still a good question...
    Gavrie Philipson, Jul 15, 2003
    #7
  8. Paul Miller enlightened us with:
    > Anytime python is accepting keyboard input, whether it's with
    > raw_input, or sitting on the command line waiting for the user to type
    > code, you can crash python by holding ctrl+shift and then pressing
    > enter.


    sybren@sybren:sybren$ python
    Python 2.2.3+ (#1, Jul 5 2003, 11:04:18)
    [GCC 3.3.1 20030626 (Debian prerelease)] on linux2
    Type "help", "copyright", "credits" or "license" for more information.
    >>> import sys
    >>> sys.stdin.readline()


    '\n'
    >>>


    As you can see, my python handles it just fine. I'm running Debian
    Unstable on my box. Guess it isn't so unstable after all ;-) I started
    python from an xterm managed by Fluxbox.

    Sybren
    --
    The problem with the world is stupidity. Not saying there should be a
    capital punishment for stupidity, but why don't we just take the
    safety labels off of everything and let the problem solve itself?
    Sybren Stuvel, Jul 15, 2003
    #8
  9. (Gavrie Philipson) writes:

    > (Paul Miller) wrote in message news:<>...
    > > I'm not sure if this is a python bug or a bug in an associated
    > > library, and I'm not even sure how to correctly report it, but here is
    > > Anytime python is accepting keyboard input, whether it's with
    > > raw_input, or sitting on the command line waiting for the user to type
    > > code, you can crash python by holding ctrl+shift and then pressing
    > > enter.
    > >
    > > This is on a RedHat 9.0 system running on an Athlon 600. Basically
    > > everything about the system is standard except for what's been updated
    > > by RedHat itself. If anyone who has the time and ability to track
    > > down this bug needs more information, please email me.

    >
    > I'm seeing the same effect on RH9, using KDE's "konsole" terminal
    > emulator.
    > When pressing Ctrl-Shift-Enter, it actually sends the ^[OM characters
    > (Escape, O, M).
    > Manually sending the key sequence Esc-O-something also crashes Python.
    >
    > Why this happens is still a good question...


    This has almost surely got to be a readline problem. Does it happen
    in (e.g.) gdb?

    Cheers,
    mwh

    PS: pressing ctrl-\ also crashes Python...
    PPS: unless you've been mucking with stty -- 'stty quit i' makes for
    an abbreviated python programming experience :)

    --
    well, take it from an old hand: the only reason it would be easier
    to program in C is that you can't easily express complex problems
    in C, so you don't. -- Erik Naggum, comp.lang.lisp
    Michael Hudson, Jul 15, 2003
    #9
  10. Paul Miller

    Cliff Wells Guest

    On Tue, 2003-07-15 at 03:17, Gavrie Philipson wrote:
    > (Paul Miller) wrote in message news:<>...
    > > I'm not sure if this is a python bug or a bug in an associated
    > > library, and I'm not even sure how to correctly report it, but here is
    > > Anytime python is accepting keyboard input, whether it's with
    > > raw_input, or sitting on the command line waiting for the user to type
    > > code, you can crash python by holding ctrl+shift and then pressing
    > > enter.
    > >
    > > This is on a RedHat 9.0 system running on an Athlon 600. Basically
    > > everything about the system is standard except for what's been updated
    > > by RedHat itself. If anyone who has the time and ability to track
    > > down this bug needs more information, please email me.

    >
    > I'm seeing the same effect on RH9, using KDE's "konsole" terminal
    > emulator.
    > When pressing Ctrl-Shift-Enter, it actually sends the ^[OM characters
    > (Escape, O, M).
    > Manually sending the key sequence Esc-O-something also crashes Python.


    Yep, here (RH9, Py2.2.2) it is as well under gnome-terminal (sending
    Esc-O-M). I'm amazed no one saw it sooner <wink>.

    --
    Cliff Wells, Software Engineer
    Logiplex Corporation (www.logiplex.net)
    (503) 978-6726 (800) 735-0555
    Cliff Wells, Jul 15, 2003
    #10
  11. Paul Miller

    Jeff Epler Guest

    On Tue, Jul 15, 2003 at 03:55:37PM +0000, Michael Hudson wrote:
    > This has almost surely got to be a readline problem. Does it happen
    > in (e.g.) gdb?


    It happens in bc, but not in gdb or my shell.

    The traceback is endless frames of
    #2094 0x4045e803 in _rl_dispatch_subseq () from /usr/lib/libreadline.so.4
    #2095 0x4045e77e in _rl_dispatch () from /usr/lib/libreadline.so.4
    ... the same in bc or python

    So does this simple C program:
    #include <stdio.h>
    #include <readline/readline.h>
    #include <readline/history.h>

    int main(void) {
    char *line = readline(">>>");
    if(line == NULL) return 1;
    printf("The user entered %s\n", line);
    free(line);
    return 0;
    }

    It seems fairly clear that this is a readline bug. I'm not sure what
    Python can do about it, if anything...

    Jeff
    Jeff Epler, Jul 16, 2003
    #11
    1. Advertising

Want to reply to this thread or ask your own question?

It takes just 2 minutes to sign up (and it's free!). Just click the sign up button to choose a username and then you can ask your own questions on the forum.
Similar Threads
  1. jaap de verwant slachter
    Replies:
    0
    Views:
    1,257
    jaap de verwant slachter
    Jul 1, 2003
  2. Roy in

    need step by step example

    Roy in, Aug 3, 2003, in forum: ASP .Net
    Replies:
    2
    Views:
    354
    Roy in
    Aug 3, 2003
  3. Steve Richter

    a step by step page

    Steve Richter, May 3, 2005, in forum: ASP .Net
    Replies:
    2
    Views:
    375
    Steve Richter
    May 3, 2005
  4. Claudio Grondi
    Replies:
    2
    Views:
    356
    Claudio Grondi
    Jul 3, 2006
  5. André
    Replies:
    1
    Views:
    425
Loading...

Share This Page