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IDProjectCategoryView StatusDate SubmittedLast Update
0008582VTK(No Category)public2009-02-23 07:492016-08-12 09:55
ReporterJoó Péter 
Assigned ToKitware Robot 
PrioritynormalSeverityminorReproducibilityrandom
StatusclosedResolutionmoved 
PlatformLinuxOSRed HatOS Version4.0.2
Product Version 
Target VersionFixed in Version 
Summary0008582: CRASH: Invoking VolumeMapperComputeGradientsStartEvent and VolumeMapperComputeGradientsEndEvent evens are not thread safe
DescriptionAt file: vtkFixedPointVolumeRayCastMapper.cxx
at method: void vtkFixedPointVolumeRayCastMapperComputeCS1CGradients(...)

This method deliberately calls the
 me->InvokeEvent( vtkCommand::VolumeMapperComputeGradientsStartEvent, NULL );
 me->InvokeEvent( vtkCommand::VolumeMapperComputeGradientsEndEvent, NULL );
methods to inform the application layer that the events
 VolumeMapperComputeGradientsStartEvent
 VolumeMapperComputeGradientsEndEvent
are about to happen.

However the vtkFixedPointVolumeRayCastMapperComputeCS1CGradients method is designed to be run on multiple threads/processor but it uses the vtkSubjectHelper::InvokeEvent method which is not thread safe.

In our case VTK created 3 threads for gradient computation.
During the computation and during the above InvokeEvent calls the vtkObjectBase::ReferenceCount member was compromised inside the our subclassed vtkCommand instance.
This means that the reference count decreased to 0 and the vtkCommand deleted while there were still references for it.
After a while the framework dereferenced that deleted class --> it lead to crash

Solution:
=========
VTK 5.2.0 as been patched in order to avoid the InvokeEvent from multiple threads. The patch consist of calling the InvokeEvent methods right before thread creation (vtkCommand::VolumeMapperComputeGradientsStartEvent) and right after the thread exit (vtkCommand::VolumeMapperComputeGradientsEndEvent)
These takes place at file
  vtkFixedPointVolumeRayCastMapper.cxx
at method
  vtkFixedPointVolumeRayCastMapper::ComputeGradients

Note:
=====
The other call for
  me->InvokeEvent( vtkCommand::VolumeMapperComputeGradientsProgressEvent, args );
has succeeded without such a problem because it was fired in case of:
  thread_id == 0
which was on purpose, I presume.
Steps To Reproducereading the code is enough to prove that such a scenario exists in VTK 5.2.0
Additional InformationIt was happened on a
- HP xw8400 Workstation (4x3.0GHz Xeon CPU, 4GB RAM, 2x150MB image disk)
- Linux version 2.6.15-2.5 (root@alfred) (gcc version 4.0.2 20051125 (Red Hat 4.0.2-8)) #1 SMP PREEMPT Tue Sep 19 10:56:25 CDT 2006
TagsNo tags attached.
Project
Type
Attached Filescxx file icon original-vtkFixedPointVolumeRayCastMapper.cxx [^] (120,079 bytes) 2009-02-23 07:58
cxx file icon patched-vtkFixedPointVolumeRayCastMapper.cxx [^] (123,007 bytes) 2009-02-23 07:58

 Relationships

  Notes
(0015288)
Joó Péter (reporter)
2009-02-23 07:58
edited on: 2009-02-23 07:59

 I have been attached the original VTK 5.2.0 file as
"original-vtkFixedPointVolumeRayCastMapper.cxx"
and our patch based on the above as
"patched-vtkFixedPointVolumeRayCastMapper.cxx"

Please review/integrate/test this fix into future versions of VTK!
(0037056)
Kitware Robot (administrator)
2016-08-12 09:55

 Resolving issue as `moved`.

This issue tracker is no longer used. Further discussion of this issue may take place in the current VTK Issues page linked in the banner at the top of this page.

 Issue History
Date Modified Username Field Change
2009-02-23 07:49 Joó Péter New Issue
2009-02-23 07:58 Joó Péter Note Added: 0015288
2009-02-23 07:58 Joó Péter File Added: original-vtkFixedPointVolumeRayCastMapper.cxx
2009-02-23 07:58 Joó Péter File Added: patched-vtkFixedPointVolumeRayCastMapper.cxx
2009-02-23 07:59 Joó Péter Note Edited: 0015288
2011-06-16 13:11 Zack Galbreath Category => (No Category)
2016-08-12 09:55 Kitware Robot Note Added: 0037056
2016-08-12 09:55 Kitware Robot Status expired => closed
2016-08-12 09:55 Kitware Robot Resolution open => moved
2016-08-12 09:55 Kitware Robot Assigned To => Kitware Robot

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