bugGNU Octave - Bugs: bug #31641, fltk print crash on cygwin


bug #31641: fltk print crash on cygwin

Submitter:  marco atzeri <matzeri>
Submitted:  Sat 13 Nov 2010 03:14:43 PM UTC
Category:  Plotting with OpenGL Severity:  3 - Normal
Priority:  5 - Normal Item Group:  Segfault, Bus Error, etc.
Status:  Fixed Assigned to:  None
Originator Name:  Open/Closed:  * Closed
Release:  * dev Operating System:  * Microsoft Windows
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Tue 28 Feb 2012 01:08:27 PM UTC, comment #18: 
Ben Abbott <bpabbott>
Project Member
Sat 25 Feb 2012 08:13:13 PM UTC, comment #17: 

Commit the patch.  I think FLTK is really coming along as a plot engine for Octave and I'd like to see it reach parity with gnuplot as soon as possible.

Rik <rik5>
Project Administrator
Sat 25 Feb 2012 06:19:52 PM UTC, comment #16: 

I ran all the the demos and produce png files for each one. The only problem isn't new (I can't print the 20th legend.m demo).

If there a no objections, I'd like to push earlier rather than latter so that any potential problems can be identified prior to the 3.8 release (when, I assume, we'll switch the default toolkit to fltk).

Ben Abbott <bpabbott>
Project Member
Sat 25 Feb 2012 04:39:55 PM UTC, comment #15: 

I added the patch to the build script
so it is included in the build process


marco atzeri <matzeri>
Sat 25 Feb 2012 04:30:10 PM UTC, comment #14: 

Ok. I've changed the status to "patch submitted".

By "back ported it to the 3.4.3 release", I assume you are indicating the Cygwin sources for Octave have been patched.

How will this be managed going forward ? Will you need to apply the patch to each new version of Octave until Cygwin fixes its bug ?

Before, taking further action, I'll apply jwe's patch and test it out on MacOS. The fltk toolkit is quite stable for me now, I'm confident I can run Soren's dump_demos() script and identify any regressions.

Ben Abbott <bpabbott>
Project Member
Sat 25 Feb 2012 05:31:21 AM UTC, comment #13: 

up to you,
it seems a specific workaround for a cygwin only bug.

I am using it as additional patch for the
cygwin package building, and I already back ported
it to the 3.4.3 release.

You can also close the bug with "patch provided",
as it is a cygwin bug and not a octave one.

marco atzeri <matzeri>
Sat 25 Feb 2012 01:04:04 AM UTC, comment #12: 

ping ... should jwe's patch be pushed ?

Ben Abbott <bpabbott>
Project Member
Tue 13 Sep 2011 09:00:37 PM UTC, comment #11: 

it seems fine.

octave:1> graphics_toolkit fltk
octave:2> sombrero
octave:3> cd /tmp/prova
octave:5> print("fltk.epsc","-depsc")
octave:6> print("fltk.psc","-dpsc")
octave:7> print("fltk.pdf","-dpdf")
octave:8> print("fltk.png","-dpng")
octave:9> print("fltk.jpg","-djpg")
octave:10> print("fltk.svg","-dsvg")
octave:12> print("fltk.dxf","-ddxf")
octave:13> print("fltk.emf","-demf")
octave:14> print("fltk.hpgl","-dhpgl")
octave:15> print("fltk.pstex","-dpstex")
octave:16> print("fltk.tikz","-dtikz")
octave:17> print("fltk.aifm","-daifm")

all these formats work and no crash

marco atzeri <matzeri>
Tue 13 Sep 2011 11:17:21 AM UTC, comment #10: 

Is there any reason that flps_renderer::draw needs to work with a file descriptor instead of a FILE pointer?  Does the attached patch avoid the problem for you?

(file #23971)

John W. Eaton <jwe>
Project Administrator
Tue 13 Sep 2011 10:49:55 AM UTC, comment #9: 

the pclose is where the segfault arise, but
I suspect is not the root cause just a consequence.

Further tracing popen/open/close on the pipe handle/descriptor
I think the sequence is :

- popen in OpenGL_fltk::draw(),
  creating pipe 5 and 6 (handle 0x20204F9C)
  (pipe 5 is closed as the communication is unidirectional)

- fdopen (6) in glps_renderer::draw
  duplicating the handle (new handle 0x2020500C)

- a lot of writing to 6

- fclose (0x2020500C) in glps_renderer::draw
  this is causing fclose to call : close(6)
Run till exit from #0  fclose (fp=0x2020500c)
    at ../../../../../src_new/newlib/libc/stdio/fclose.c:116

Breakpoint 6, close (fd=6)
    at /pub/cygwin/cvs/src_new/winsup/cygwin/syscalls.cc:1214

- pclose(0x20204F9C) in OpenGL_fltk::draw()
  that SEGFAULT's as fd=6 is already closed

The close(6) seems an abnormal beahviour of fclose as
there is another FILE handle still open.

What I don't know if there is a bug in fclose or
if the behaviour is correct due to some settings.

marco atzeri <matzeri>
Tue 13 Sep 2011 10:25:46 AM UTC, comment #8: 

What is the stack trace at the point of the crash?

There is no fhandler_pipe variable in the Octave sources, so where is this crash happening?

If I set a breakpoint in pclose and execute your latest commands, I stop here:

#0  __new_pclose (fp=0x1141880) at pclose.c:43
#1  0x00007ffff740780d in octave_pclose (f=0x1141880)
    at /home/jwe/src/octave/src/sysdep.cc:436
#2  0x00007fffeab6dc89 in OpenGL_fltk::draw (this=0xf97540)
    at /home/jwe/src/octave/src/DLD-FUNCTIONS/__init_fltk__.cc:166
#3  0x00007ffff4ececa2 in Fl_Gl_Window::flush() ()
   from /usr/lib/x86_64-linux-gnu/libfltk_gl.so.1.1
#4  0x00007ffff4c48542 in Fl::flush() ()
   from /usr/lib/x86_64-linux-gnu/libfltk.so.1.1
#5  0x00007ffff4c49bec in Fl::wait(double) ()
   from /usr/lib/x86_64-linux-gnu/libfltk.so.1.1
#6  0x00007ffff4c49c8d in Fl::check() ()
   from /usr/lib/x86_64-linux-gnu/libfltk.so.1.1
#7  0x00007fffeab64888 in __fltk_redraw__ ()
    at /home/jwe/src/octave/src/DLD-FUNCTIONS/__init_fltk__.cc:1775
#8  0x00007fffeab6502e in F__fltk_redraw__ ()
    at /home/jwe/src/octave/src/DLD-FUNCTIONS/__init_fltk__.cc:1930
#9  0x00007ffff7467034 in octave_builtin::do_multi_index_op (this=0x6e61a0,
    nargout=0, args=..., lvalue_list=0x0)
    at /home/jwe/src/octave/src/ov-builtin.cc:131

The code in OpenGL_fltk::draw that ultimately calls pclose is

    if (print_mode)
        FILE *fp = octave_popen (print_cmd.c_str (), "w");
        glps_renderer rend (fileno (fp), print_term);

        rend.draw (gh_manager::get_object (number));

        octave_pclose (fp);
        print_mode = false;

This seems a valid use of popen and pclose.  I don't know what fhandler_pipe is or how to set it.  Where does it come from and why is it not set but then apparently used?

John W. Eaton <jwe>
Project Administrator
Sat 10 Sep 2011 08:53:15 AM UTC, comment #7: 

restarting the search, after long time

the sequence

graphics_toolkit fltk;
plot (x,x)
print (fltk.png","-dpng")

still causes segfault on octave-dev

The cause is system pclose called with a
NULL handler for the involved pipe

(gdb) p fp
$6 = (FILE *) 0x20204f94
(gdb) call fileno(fp)
$7 = 6
p fh
$8 = (fhandler_pipe *) 0x0

One strange issues:

changing the sequence to

graphics_toolkit fltk;
plot (x)
set (gcf,'visible','off')
print (gcf,"test_invisible.png","-dpng")
set (gcf,'visible','on')

the segfault is not on the print but on the last set

marco atzeri <matzeri>
Fri 04 Feb 2011 11:35:53 PM UTC, comment #6: 

I uploaded on


the compressed strace for both fltk case that crashes
and gnuplot case that works.

For what I can see, for gnuplot the sequence is

octave > gnuplot > gs > octave (that exit)

while for fltk

octave  > gs (unable to return and exit)

Any suggestion how to further investigate ?

marco atzeri <matzeri>
Fri 04 Feb 2011 07:07:11 PM UTC, comment #5: 

I have add Ben to the Mail Notification Carbon-Copy List.


Tatsuro MATSUOKA <tmacchant>
Fri 04 Feb 2011 06:36:03 PM UTC, comment #4: 

on 3.2.91-1 build on cygwin 1.7.7 it is enough

graphics_toolkit ("fltk")

      9 [main] octave 3792 E:\cygwin2\bin\octave-3.3.91.exe: *** fatal error - Internal error: TP_NUM_C_BUFS too small.
Stack trace:
Frame     Function  Args
0022D010  6102749B  (0022D010, 00000000, 00000000, 00000000)
0022D300  6102749B  (61177B80, 00008000, 00000000, 61179977)
0022E330  61004AFB  (611C408C, 7C8092EF, 002300D4, 00230000)
0022E350  610ECF78  (0022F5E8, 7C900000, 00000000, 0022E37C)
0022F610  6109540F  (612013E0, DF0DF046, 0022F6F0, 0022F5F8)
011A1BDC  6102231D  (6F2F6572, 76617463, 2E332F65, 31392E33)
End of stack trace

the file fltk.png is created and it is fine.

marco atzeri <matzeri>
Thu 03 Feb 2011 05:51:34 PM UTC, comment #3: 

I add my mail address in the cc. list


Tatsuro MATSUOKA <tmacchant>
Mon 15 Nov 2010 02:29:47 PM UTC, comment #2: 

Under GDB

[New thread 27684.0x700c]
[New thread 27684.0x1914]
backend is fltk
print fltk-aifm  -daifm
[New thread 27684.0x76b8]

Program exited with code 030000000005.

and of course

(gdb) bt
No stack.

marco atzeri <matzeri>
Sat 13 Nov 2010 03:48:19 PM UTC, comment #1: 

I don't see a crash on my Debian system, but I do see the following error:

octave:1> source test_printing.m
octave:2> test_printing ("fltk")
backend is fltk
print fltk-aifm  -daifm
print fltk-dxf  -ddxf
print fltk-emf  -demf
print fltk-epsc  -depsc
print fltk-epslatex  -depslatex
print fltk-hpgl  -dhpgl
print fltk-jpg  -djpg
print fltk-pdf  -dpdf
print fltk-pdf  -dpdf -append
   **** Error: Cannot find a %%EOF marker anywhere in the file.
   **** Warning:  An error occurred while reading an XREF table.
   **** The file has been damaged.  This may have been caused
   **** by a problem while converting or transfering the file.
   **** Ghostscript will attempt to recover the data.
Error: /undefined in --run--
Operand stack:
   5   0   1   --dict:5/5(ro)(G)--   (obj)
Execution stack:
   %interp_exit   .runexec2   --nostringval--   --nostringval--   --nostringval--   2   %stopped_push   --nostringval--   --nostringval--   --nostringval--   false   1   %stopped_push   1878   1   3   %oparray_pop   1877   1   3   %oparray_pop   1861   1   3   %oparray_pop   --nostringval--   --nostringval--   --nostringval--   --nostringval--   --nostringval--   --nostringval--   false   1   %stopped_push   --nostringval--   %loop_continue   --nostringval--
Dictionary stack:
   --dict:1159/1684(ro)(G)--   --dict:1/20(G)--   --dict:75/200(L)--   --dict:75/200(L)--   --dict:108/127(ro)(G)--   --dict:290/300(ro)(G)--   --dict:20/25(L)--
Current allocation mode is local
GPL Ghostscript 8.71: Unrecoverable error, exit code 1
print fltk-pdflatex  -dpdflatex
print fltk-png  -dpng
print fltk-psc  -dpsc
print fltk-psc  -dpsc -append
print fltk-pslatex  -dpslatex
print fltk-pstex  -dpstex
print fltk-svg  -dsvg
print fltk-tikz  -dtikz

Can you please try running Octave under gdb and get a backtrace to see precisely where the crash is happening?

John W. Eaton <jwe>
Project Administrator
Sat 13 Nov 2010 03:14:43 PM UTC, original submission:  

latest test on

$ hg tip
changeset:   11238:1783b360976f
tag:         tip
user:        John W. Eaton <jwe@octave.org>
date:        Thu Nov 11 02:30:32 2010 -0500
summary:     also consider parent classes when checking if class methods are out of date

Print with fltk cause 

octave:2> source test_printing.m
octave:3> test_printing("fltk")
backend is fltk
print fltk-aifm  -daifm
panic: Segmentation fault -- stopping myself...
attempting to save variables to `octave-core'...
save to `octave-core' complete
Segmentation fault

This is happening for any output graphic format.

marco atzeri <matzeri>


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Attach Files:

Attached Files
file #23971:  diffs.txt added by jwe (2KiB - text/plain)
file #22001:  test_printing.m added by matzeri (5KiB - application/octet-stream)


Depends on the following items: None found

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    Follow 8 latest changes.

    Date Changed by Updated Field Previous Value => Replaced by
    2012-02-28 bpabbott StatusPatch Submitted Fixed
        Open/ClosedOpen Closed
    2012-02-25 bpabbott StatusNone Patch Submitted
    2012-02-18 bpabbott CategoryPlotting Plotting with OpenGL
    2011-09-13 jwe Attached File- Added diffs.txt, #23971
    2011-02-04 tmacchant Carbon-Copy- Added -email is unavailable-
    2011-02-03 tmacchant Carbon-Copy- Added -email is unavailable-
    2010-11-13 matzeri Attached File- Added test_printing.m, #22001

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