c++opencvmemory-leaksvalgrindcielab

valgrind: errors with cvCvtColor in opencv


Here is my very simple code:

#include <opencv/highgui.h>
#include <opencv/cv.h>
#include <iostream>
using namespace std;
using namespace cv;
int main(int argc, char** argv)
{
    for(int i=0;i<2;i++){
        ostringstream tmp;
        tmp << "/vol/test1/" << i << ".jpg";

        IplImage * img = cvLoadImage(tmp.str().c_str());                  //line #12
        IplImage* imgc = cvCreateImage(cvGetSize(img), img->depth,3);
        cvCvtColor(img, imgc, CV_BGR2Lab);                                //line #14
        cvReleaseImage(&img);
        img = imgc;
        cvReleaseImage(&img);
    }
    return 0;
}

The program just loads 2 images, and transforms them to CIELab space. However, Valgrind throws the following errors:

==31879== LEAK SUMMARY:
==31879==    definitely lost: 0 bytes in 0 blocks
==31879==    indirectly lost: 0 bytes in 0 blocks
==31879==      possibly lost: 0 bytes in 0 blocks
==31879==    still reachable: 14,456 bytes in 6 blocks
==31879==         suppressed: 0 bytes in 0 blocks
==31879== 
==31879== ERROR SUMMARY: 903892 errors from 3 contexts (suppressed: 2 from 2)

Further check with -g --show-reachable=yes gives me the details of the leak (the reports for block 1-4 are as the same as block 5 so I do not post it here):

==31879== 2,072 bytes in 1 blocks are still reachable in loss record 5 of 6
==31879==    at 0x4C2B6CD: malloc (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==31879==    by 0x10B3DF5A: ??? (in /usr/lib/x86_64-linux-gnu/libpixman-1.so.0.30.2)
==31879==    by 0x10B40D3F: ??? (in /usr/lib/x86_64-linux-gnu/libpixman-1.so.0.30.2)
==31879==    by 0x10B03A68: ??? (in /usr/lib/x86_64-linux-gnu/libpixman-1.so.0.30.2)
==31879==    by 0x400F305: call_init.part.0 (dl-init.c:85)
==31879==    by 0x400F3DE: _dl_init (dl-init.c:52)
==31879==    by 0x40016E9: ??? (in /lib/x86_64-linux-gnu/ld-2.15.so)
==31879== 
==31879== 4,096 bytes in 1 blocks are still reachable in loss record 6 of 6
==31879==    at 0x4C2B6CD: malloc (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==31879==    by 0x64870B7: libjpeg_general_init (in /usr/lib/x86_64-linux-gnu/libjpeg.so.8.0.2)
==31879==    by 0x400F305: call_init.part.0 (dl-init.c:85)
==31879==    by 0x400F3DE: _dl_init (dl-init.c:52)
==31879==    by 0x40016E9: ??? (in /lib/x86_64-linux-gnu/ld-2.15.so)

Since the memory leak is "still reachable", I think I can safely ignore it. But it is the Error Summary of 903892 errors that concerns me. I rerun valgrind with --track-origins=yes:

==31879== ERROR SUMMARY: 903892 errors from 3 contexts (suppressed: 2 from 2)
==31879== 
==31879== 301229 errors in context 1 of 3:
==31879== Use of uninitialised value of size 8
==31879==    at 0x55219F0: cv::CvtColorLoop_Invoker<cv::RGB2Lab_b>::operator()(cv::Range const&) const (in /vol/Toolkits/opencv-2.4.10/release/lib/libopencv_imgproc.so.2.4.10)
==31879==    by 0x5536152: cv::cvtColor(cv::_InputArray const&, cv::_OutputArray const&, int, int) (in /vol/Toolkits/opencv-2.4.10/release/lib/libopencv_imgproc.so.2.4.10)
==31879==    by 0x55403A8: cvCvtColor (in /vol/Toolkits/opencv-2.4.10/release/lib/libopencv_imgproc.so.2.4.10)
==31879==    by 0x400DEB: main (main.cpp:14)
==31879==  Uninitialised value was created by a heap allocation
==31879==    at 0x4C2B6CD: malloc (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==31879==    by 0x64ABA74: ??? (in /usr/lib/x86_64-linux-gnu/libjpeg.so.8.0.2)
==31879==    by 0x64ABD02: ??? (in /usr/lib/x86_64-linux-gnu/libjpeg.so.8.0.2)
==31879==    by 0x649EFF9: jinit_d_main_controller (in /usr/lib/x86_64-linux-gnu/libjpeg.so.8.0.2)
==31879==    by 0x64A22BB: jinit_master_decompress (in /usr/lib/x86_64-linux-gnu/libjpeg.so.8.0.2)
==31879==    by 0x64991D4: jpeg_start_decompress (in /usr/lib/x86_64-linux-gnu/libjpeg.so.8.0.2)
==31879==    by 0x4E64621: cv::JpegDecoder::readData(cv::Mat&) (in /vol/Toolkits/opencv-2.4.10/release/lib/libopencv_highgui.so.2.4.10)
==31879==    by 0x4E4AC8C: cv::imread_(std::string const&, int, int, cv::Mat*) (in /vol/Toolkits/opencv-2.4.10/release/lib/libopencv_highgui.so.2.4.10)
==31879==    by 0x4E4B13B: cvLoadImage (in /vol/Toolkits/opencv-2.4.10/release/lib/libopencv_highgui.so.2.4.10)
==31879==    by 0x400D9D: main (main.cpp:12)

(The reports for context 2 and 3 are as the same as context 1 so I do not post it here). The errors seem come from line 12 and 14 in my code. What is wrong? or Am I missing something here?

Side note: if I scan more images, the report for leak memory is the same, but number of errors in Error Summary increases linearly. My program runs to segmentation fault after scanning ~3000 images.


Solution

  • please, avoid all deprecated IplImages, and use cv::Mat, and the c++ api instead.

    #include <opencv2/opencv.hpp> // c++ headers
    #include <iostream>
    using namespace std;
    using namespace cv;
    int main(int argc, char** argv)
    {
        for(int i=0;i<2;i++){
            ostringstream tmp;
            tmp << "/vol/test1/" << i << ".jpg";
    
            Mat img = imread(tmp.str().c_str());              
            Mat imgc; // no pre-allocation nessecary
            cvtColor(img, imgc, CV_BGR2Lab);                  
            // no manual release nessecary        
        }
        return 0;
    }