PointCloudLibrary/pcl

Poisson reconstruction in parallel threads segfaults

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#1,845 opened on Mar 16, 2017

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help wantedkind: bugkind: todomodule: surface

Description

Your Environment

  • Operating System and version: Ubuntu 16.10
  • Compiler: gcc 6.2
  • PCL Version: 1.8 as packaged for Ubuntu

Expected Behavior

Two threads should be able to create two different instances of pcl::Poisson and run them on two different input clouds at the same time.

Current Behavior

Segfault

Code to Reproduce

http://pastebin.com/yJrpcpTL

Contributor guide

Tech stack
cpp
Domain
backend
Issue type
bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
5
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
over 1 week
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
stale
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
clear
Prerequisites
C++multi threadingPCL basics
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
20
Research direction
The issue reports a segfault when creating two separate pcl::Poisson instances in parallel threads. The pastebin code demonstrates the crash. Likely cause is non thread safe global or static variables in the Poisson reconstruction algorithm. Investigate the source files in pcl/surface/include/pcl/surface/poisson.hpp and related implementations. Check for mutable global state or unsynchronized access to shared resources. A fix would involve making the Poisson class reentrant, perhaps by moving global state to instance variables or adding mutex locks.