RE: Request help debugging octave-video in mxe-octave

[JohnD]

> -----Original Message-----
> From: JohnD [mailto:address@hidden
> Sent: Thursday, January 07, 2016 4:39 PM
> To: 'John Swensen'
> Cc: address@hidden; 'Andreas Weber'
> Subject: RE: Request help debugging octave-video in mxe-octave
> 
> 
> 
> > -----Original Message-----
> > From: JohnD [mailto:address@hidden
> > Sent: Thursday, January 07, 2016 4:27 PM
> > To: 'John Swensen'
> > Cc: address@hidden; 'Andreas Weber'
> > Subject: RE: Request help debugging octave-video in mxe-octave
> >
> >
> >
> > > -----Original Message-----
> > > From: John Swensen [mailto:address@hidden
> > > Sent: Thursday, January 07, 2016 3:19 PM
> > > To: JohnD
> > > Cc: address@hidden; Andreas Weber
> > > Subject: Re: Request help debugging octave-video in mxe-octave
> > >
> > >
> > > > On Jan 7, 2016, at 12:01 PM, JohnD <address@hidden>
> > > wrote:
> > > >
> > > >
> > > >
> > > >> -----Original Message-----
> > > >> From: JohnD [mailto:address@hidden
> > > >> Sent: Thursday, January 07, 2016 8:02 AM
> > > >> To: address@hidden
> > > >> Cc: 'John Swensen'; 'Andreas Weber'
> > > >> Subject: Re: Request help debugging octave-video in mxe-octave
> > > >>
> > > >>>
> > > >>> Message: 3
> > > >>> Date: Tue, 5 Jan 2016 10:21:55 -0800
> > > >>> From: John Swensen <address@hidden>
> > > >>> To: Andreas Weber <address@hidden>
> > > >>> Cc: octave-maintainers <address@hidden>
> > > >>> Subject: Re: Request help debugging octave-video in mxe-octave
> > > >>> Message-ID: <9B32F36A-EC93-4D5B-A3B0-
> address@hidden>
> > > >>> Content-Type: text/plain; charset=utf-8
> > > >>>
> > > >>>
> > > >>>> On Jan 1, 2016, at 10:58 AM, Andreas Weber
> > > >>>> <address@hidden>
> > > > wrote:
> > > >>>>
> > > >>>> Dear maintainers,
> > > >>>>
> > > >>>> I need some help debugging octave-video with ffmpeg in mxe-octave.
> > > >>>> Sometimes I get a strange segmentation fault in the AVHandler
> > > >> destructor.
> > > >>>>
> > > >>>> What I've done so far:
> > > >>>> Crosscompile mxe-octave on Debian Jessie with $ ./configure
> > > >>>> --disable-strip-dist-files --enable-devel-tools
> > > >>>> --enable-binary-packages $ make gdb ffmpeg zip-dist
> > > >>>>
> > > >>>> In Windows7, extract zip, and grab code from
> > > >>>> http://sourceforge.net/p/octave/video/ci/default/tree/
> > > >>>> run octave in CLI mode, getpid, attach gdb.
> > > >>>>
> > > >>>> Back in Octave:
> > > >>>>>> cd octave/video/src
> > > >>>>>> test avifile
> > > >>>>
> > > >>>> This sometimes works (PASS 1/1) and sometimes fails at
> > > >>>> different
> > > > places:
> > > >>>>
> > > >>>> ----------------------------------------------------
> > > >>>> Program received signal SIGSEGV, Segmentation fault.
> > > >>>> [Switching to Thread 2648.0x7f4]
> > > >>>> 0x7795e3c6 in ntdll!RtlInitUnicodeString () from
> > > >>>> C:\Windows\SysWOW64\ntdll.dll
> > > >>>> (gdb)
> > > >>>> Continuing.
> > > >>>>
> > > >>>> --------------------------------------------------
> > > >>>> Program received signal SIGSEGV, Segmentation fault.
> > > >>>> [Switching to Thread 3212.0xe9c]
> > > >>>> 0x77963aa8 in ntdll!RtlQueryPerformanceCounter ()  from
> > > >>>> C:\Windows\SysWOW64\ntdll.dll
> > > >>>> (gdb) bt
> > > >>>> #0  0x77963aa8 in ntdll!RtlQueryPerformanceCounter ()  from
> > > >>>> C:\Windows\SysWOW64\ntdll.dll
> > > >>>> #1  0x77962c7a in ntdll!RtlQueryPerformanceCounter ()  from
> > > >>>> C:\Windows\SysWOW64\ntdll.dll
> > > >>>> #2  0x77962b65 in ntdll!RtlQueryPerformanceCounter ()  from
> > > >>>> C:\Windows\SysWOW64\ntdll.dll
> > > >>>> #3  0x76b698cd in msvcrt!free () from
> > > >>>> C:\Windows\syswow64\msvcrt.dll
> > > >>>> #4  0x17aa0000 in ?? ()
> > > >>>> #5  0x1c0159fe in avpriv_mpa_decode_header ()  from
> > > >>>> C:\octave-dbg\octave-4.0.0\bin\avcodec-56.dll
> > > >>>> #6  0x1c3bcce9 in avcodec-56!av_dct_end ()  from
> > > >>>> C:\octave-dbg\octave-4.0.0\bin\avcodec-56.dll
> > > >>>> #7  0x1c3ce86e in avcodec_close ()  from
> > > >>>> C:\octave-dbg\octave-4.0.0\bin\avcodec-56.dll
> > > >>>> #8  0x6660167c in AVHandler::~AVHandler (this=0x1bacd708,
> > > >>>>   __in_chrg=<optimized out>) at AVHandler.cc:83
> > > >>>> #9  0x6660384a in Avifile::~Avifile (this=0x1bc20c90,
> > > >>>>
> > > >>>> ---------------------------------------------------------
> > > >>>> Program received signal SIGSEGV, Segmentation fault.
> > > >>>> [Switching to Thread 3184.0xe48]
> > > >>>> 0x77962e33 in ntdll!RtlQueryPerformanceCounter ()  from
> > > >>>> C:\Windows\SysWOW64\ntdll.dll
> > > >>>> (gdb) bt
> > > >>>> #0  0x77962e33 in ntdll!RtlQueryPerformanceCounter ()  from
> > > >>>> C:\Windows\SysWOW64\ntdll.dll
> > > >>>> #1  0x77962b65 in ntdll!RtlQueryPerformanceCounter ()  from
> > > >>>> C:\Windows\SysWOW64\ntdll.dll
> > > >>>> #2  0x76b698cd in msvcrt!free () from
> > > >>>> C:\Windows\syswow64\msvcrt.dll
> > > >>>> #3  0x17a70000 in ?? ()
> > > >>>> #4  0x0128b8bc in ~ArrayRep (this=0x1bbfaa70,
> > > >>>> __in_chrg=<optimized
> > > > out>)
> > > >>>>   at
> > > >>>> /home/andy/src/mxe-octave/tmp-stable-octave/octave-4.0.0/liboct
> > > >>>> av
> > > >>>> e/
> > > >>>> a
> > > >>>> rr
> > > >>>> ay/
> > > >>>> Array.h:89
> > > >>>> #5  Array<double>::~Array (this=0x0, __in_chrg=<optimized out>)
> > > >>>>   at
> > > >>>> /home/andy/src/mxe-octave/tmp-stable-octave/octave-4.0.0/liboct
> > > >>>> av
> > > >>>> e/
> > > >>>> a
> > > >>>> rr
> > > >>>> ay/
> > > >>>> Array.h:223
> > > >>>> #6  0x011e3b83 in ~MArray (this=0x1bb13a40,
> > > >>>> __in_chrg=<optimized
> > out>)
> > > >>>>   at
> > > >>>> /home/andy/src/mxe-octave/tmp-stable-octave/octave-4.0.0/liboct
> > > >>>> av
> > > >>>> e/
> > > >>>> a
> > > >>>> rr
> > > >>>> ay/
> > > >>>> MArray.h:63
> > > >>>> #7  ~NDArray (this=0x1bb13a40, __in_chrg=<optimized out>)
> > > >>>>   at
> > > >>>> /home/andy/src/mxe-octave/tmp-stable-octave/octave-4.0.0/liboct
> > > >>>> av
> > > >>>> e/
> > > >>>> a
> > > >>>> rr
> > > >>>> ay/
> > > >>>> dNDArray.h:35
> > > >>>> #8  ~octave_base_matrix (this=0x1bb13a38, __in_chrg=<optimized
> out>)
> > > >>>>   at
> > > >>>> /home/andy/src/mxe-octave/tmp-stable-octave/octave-4.0.0/libint
> > > >>>> er
> > > >>>> p/
> > > >>>> o
> > > >>>> ct
> > > >>>> ave
> > > >>>> -value/ov-base-mat.h:68
> > > >>>> #9  ~octave_matrix (this=0x1bb13a38, __in_chrg=<optimized out>)
> > > >>>>   at
> > > >>>> /home/andy/src/mxe-octave/tmp-stable-octave/octave-4.0.0/libint
> > > >>>> er
> > > >>>> p/
> > > >>>> o
> > > >>>> ct
> > > >>>> ave
> > > >>>> -value/ov-re-mat.h:97
> > > >>>>
> > > >>>> Any ideas what I could try?
> > > >>>> Thank you, Andy
> > > >>>>
> > > >>>
> > > >>> My initial thought would be that the ?clear m? in the test
> > > >>> script is
> > > >> forcing the
> > > >>> destructor to be called and it is possible that stuff is still
> > > >>> going on in
> > > >> the encoding
> > > >>> process (ffmpeg is sometimes multithreaded depending on the
> > > >>> codec, and
> > > >> there
> > > >>> could still be file IO going on).
> > > >>>
> > > >>> As a first test, I would put a big delay (say 5-10 seconds)
> > > >>> between the
> > > >> ?endfor'
> > > >>> and the ?clear m'  in the avifile test. If it is just a matter
> > > >>> of trying
> > > >> to delete the
> > > >>> ffmpeg codec and other objects before they are ready to be
> > > >>> deleted, that
> > > >> could
> > > >>> cause a segfault. I know there is a chunk of code just previous
> > > >>> to the
> > > >> segfault
> > > >>> location that *should be* cleaning things up before closing
> > > >>> everything,
> > > >> but
> > > >>> maybe it isn?t cleaning up correctly?
> > > >>>
> > > >>> John S.
> > > >>>
> > > >>
> > > >>
> > > >> Ok - I can see it on my build as well - it doesn't happen all the
> > > >> time
> > > >>
> > > >> I used to see it crash on calling avifile before 1.2.1, but don't
> > > >> seem to
> > > > see it
> > > >> there anymore, but do see it when running the video test script
> > > >
> > > > Not sure if this solves it, but ...
> > > >
> > > > Looking at the video package source code:
> > > > AviFile has a copy constructor that is private, so normally wont be 
> > > > used.
> > > > However I beleive the default AviFile constructor DOES use it
> > > > with
> > > > *this=AviFile("default.avi")
> > > >
> > > > The copy constructor blindly sets 'av' to point to the same value
> > > > as what the other constructor, so when it frees all the
> > > > octave_base_value objects, it has multiple base value objects
> > > > trying to free the same 'av’ pointer
> > > >
> > >
> > > That may be a problem, but I don’t think the default constructor is
> > > ever being called during the avifile test and I don’t ever see the
> > > warning "avifile: copy constructor shouldn't be called” that should
> > > occur if the copy constructor was actually being called.
> >
> > Isnt the '=' operator going to do a similar thing - its going to
> > blindly copy the av pointer between objects
> 
> 
> I just attached the patch to Bug 46833 that I applied to the released package 
> of
> video - no crashes with the addframe test


I guess I will take that back - the constructor or '=' wasn’t the issue, I had 
2 changes in the files - the other being in AVHandler.cc, changing the 
video_outbuff = malloc to the video_outbuff = av_malloc.

On just changing the devel code for the av_malloc, it doesn’t crash, so I guess 
that is the issue - the free of the memory is using av_free.

It might be good to remove the default contructor still and use a default value 
for AviFile::AviFile(std::string fn) to make it a default.