[FFmpeg-trac] #2216(avcodec:new): memory leak in calling avcodec_alloc_context3 and then avcodec_copy_context

[FFmpeg]

#2216: memory leak in calling avcodec_alloc_context3 and then avcodec_copy_context
--------------------------------+-----------------------------------
             Reporter:  vinxxe  |                    Owner:
                 Type:  defect  |                   Status:  new
             Priority:  normal  |                Component:  avcodec
              Version:  1.1.1   |               Resolution:
             Keywords:  leak    |               Blocked By:
             Blocking:          |  Reproduced by developer:  1
Analyzed by developer:  1       |
--------------------------------+-----------------------------------

Comment (by vinxxe):

 Replying to [comment:1 cehoyos]:
 > Please provide source code that allows to reproduce the leak together
 with valgrind output.
 here's the code and a movie file to reproduce the leak. to compile I used
 this command
 {{{
 gcc -g -ggdb -o leak main.c -lpthread -lm -lz -lbz2 -lswscale -lavdevice
 -lavformat -lavcodec -lavutil -lmp3lame -lx264 -lvpx -lvorbis -lvorbisenc
 -lfaac -lva -ltcmalloc
 }}}

 {{{
 /*#######################################################*/
 #include <libavcodec/avcodec.h>
 #include <libavformat/avformat.h>
 #include <libavutil/log.h>

 int main(int argc, char **argv){
   AVFormatContext *formatCtx=NULL;
   AVCodec         *codec=NULL;
   AVCodecContext  *SourceCodecCtx=NULL;
   AVCodecContext  *DestCodecCtx=NULL;
   int i=0;

   av_register_all();
   av_log_set_level(100);

   avformat_open_input(&formatCtx, "Loading.mp4", NULL, NULL);
   SourceCodecCtx=formatCtx->streams[0]->codec;
   codec=avcodec_find_decoder(SourceCodecCtx->codec_id);

   for (i=0;i<10;i++){
     DestCodecCtx = avcodec_alloc_context3(codec);
     avcodec_copy_context(DestCodecCtx,SourceCodecCtx);
     av_free(DestCodecCtx);
   }

   av_free(SourceCodecCtx);
   avformat_close_input(&formatCtx);

 }

 /*#######################################################*/
 }}}

 Unfortunately valgrind fails to detect the leak (perhaps due to the use of
 tcmalloc ?) but the heap profiler of the tcmalloc lib succeeds. here's
 both the valgrind output and the tcmalloc heap profiler output.

 TCMALLOC HEAP PROFILER OUTPUT :
 {{{
 [mov,mp4,m4a,3gp,3g2,mj2 @ 0x2b50000] Format mov,mp4,m4a,3gp,3g2,mj2
 probed with size=2048 and score=100
 [mov,mp4,m4a,3gp,3g2,mj2 @ 0x2b50000] ISO: File Type Major Brand: mp42
 [AVIOContext @ 0x2b68000] Statistics: 38663 bytes read, 1 seeks
 Leak check _main_ detected leaks of 4230690 bytes in 20 objects
 The 2 largest leaks:
 Using local file ./leak.
 Leak of 4230080 bytes in 10 objects allocated from:
         @ af5d8a av_mallocz
 Leak of 610 bytes in 10 objects allocated from:
         @ af5cf5 av_malloc


 If the preceding stack traces are not enough to find the leaks, try
 running THIS shell command:

 pprof ./leak "/tmp/leak.19693._main_-end.heap" --inuse_objects --lines
 --heapcheck  --edgefraction=1e-10 --nodefraction=1e-10 --gv

 If you are still puzzled about why the leaks are there, try rerunning this
 program with HEAP_CHECK_TEST_POINTER_ALIGNMENT=1 and/or with
 HEAP_CHECK_MAX_POINTER_OFFSET=-1
 If the leak report occurs in a small fraction of runs, try running with
 TCMALLOC_MAX_FREE_QUEUE_SIZE of few hundred MB or with
 TCMALLOC_RECLAIM_MEMORY=false, it might help find leaks more repeatably
 Exiting with error code (instead of crashing) because of whole-program
 memory leaks
 }}}

 VALGRIND OUTPUT :

 {{{
 ==19649== Memcheck, a memory error detector
 ==19649== Copyright (C) 2002-2009, and GNU GPL'd, by Julian Seward et al.
 ==19649== Using Valgrind-3.6.0.SVN-Debian and LibVEX; rerun with -h for
 copyright info
 ==19649== Command: ./leak
 ==19649==
 [mov,mp4,m4a,3gp,3g2,mj2 @ 0x4348000] Format mov,mp4,m4a,3gp,3g2,mj2
 probed with size=2048 and score=100
 [mov,mp4,m4a,3gp,3g2,mj2 @ 0x4348000] ISO: File Type Major Brand: mp42
 [AVIOContext @ 0x4360000] Statistics: 38663 bytes read, 1 seeks
 ==19649==
 ==19649== HEAP SUMMARY:
 ==19649==     in use at exit: 0 bytes in 0 blocks
 ==19649==   total heap usage: 0 allocs, 0 frees, 0 bytes allocated
 ==19649==
 ==19649== All heap blocks were freed -- no leaks are possible
 ==19649==
 ==19649== For counts of detected and suppressed errors, rerun with: -v
 ==19649== ERROR SUMMARY: 0 errors from 0 contexts (suppressed: 4 from 4)
 }}}

-- 
Ticket URL: <https://ffmpeg.org/trac/ffmpeg/ticket/2216#comment:2>
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