Bug 1220831

Summary:	plotyy crashes octave due to problem in the default graphics engine (FLTK)
Product:	[Fedora] Fedora	Reporter:	Przemek Klosowski <przemek>
Component:	octave	Assignee:	Jaromír Cápík <jcapik>
Status:	CLOSED DUPLICATE	QA Contact:	Fedora Extras Quality Assurance <extras-qa>
Severity:	unspecified	Docs Contact:
Priority:	unspecified
Version:	21	CC:	alex, fkluknav, jcapik, mmahut, orion, ovasik, rakesh.pandit, susi.lehtola
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Fixed In Version:		Doc Type:	Bug Fix
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Last Closed:	2015-05-12 15:50:56 UTC	Type:	Bug
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oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
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Description Przemek Klosowski 2015-05-12 14:56:26 UTC

Description of problem:
plotyy crashes octave due to problem in the default graphics engine (FLTK)

Version-Release number of selected component (if applicable):
octave-3.8.2-9.fc21.x86_64

How reproducible: every time

Steps to Reproduce:
1. run octave
2. x=1:10; plotyy(x,x,x,x);

Actual results: Octave crashes with SEGV

Expected results: Octave does not crash and displays a graph

Comment 1 Przemek Klosowski 2015-05-12 14:57:18 UTC

This is caused by FLTK because 

graphics_toolkit("gnuplot")
x=1:10;plotyy(x,x,x,x);

works fine and gives expected plot

Comment 2 Przemek Klosowski 2015-05-12 15:02:04 UTC

The crash is caused by a corrupted 'overlay' variable  in Fl_Gl_Window::show (this=0xd0e180) at Fl_Gl_Window.cxx:87 :

 if (overlay && overlay != this) ((Fl_Gl_Window*)overlay)->show();

p overlay
$1 = (void *) 0x3ff0000000000000

p *(Fl_Gl_Window*)overlay
Cannot access memory at address 0x3ff0000000000000

Comment 3 Przemek Klosowski 2015-05-12 15:07:26 UTC

Just for completeness, I have fltk-1.3.3-2.fc21.x86_64

Comment 4 Orion Poplawski 2015-05-12 15:50:56 UTC


*** This bug has been marked as a duplicate of bug 1218360 ***

Comment 5 Przemek Klosowski 2015-05-12 15:56:32 UTC

There seems to be a problem with the multiple definition of overlay. When Octave crashes, overlay as seen in the crashing leaf procedure Fl_Gl_Window::show is corrupted to (void *) 0x3ff0000000000000 (see comment 2), but up in the call stack it is different: 

up
 #1  0x00007fffeef98a90 in Fl_Window::handle (this=this@entry=0xcd7f30, 
    ev=ev@entry=16) at Fl.cxx:1613

p overlay
  $6 = {int (const WINDOW *, WINDOW *)} 0x330a6121e0 <overlay>

which happens to be identical to the definition of overlay just after Octave starts.