[gst-devel] Question: How do I obtain a better gdb back trace of segmentation faults?

[Benjamin Otte]

The problem is probably that you should not debug gst-launch, but
gst-launch-0.8. The unversioned tools are just wrapper binaries that
select the newest versioned tool and execute that.

Another problem might be that you run uninstalled and debugged a libtool
wrapper. If you run indeed uninstalled, you should not debug
./gst-launch-0.8, but .libs/lt-gst-launch-0.8

So you probably got a backtrace from a wrapper there.
At least those are the two most common pitfalls.

Benjamin



On Thu, 6 Jan 2005, David Parr wrote:

> Hello,
>
> I have submitted a defect related to a segmentation fault in videobox plugin (#163159).  I am new to the Linux platform, but have been developing software for years and need some assistance.
>
> My backtrace contained only a few symbols, and I would like advise on the correct way to compile/link or better use gdb so that I can submit more useful information in the future.
>
> I would appreciate any help/advise that you can spare.  The steps that I followed, and the output that I obtained are below.
>
> Related question - is this the preferred forum for these types of questions / requests?
>
> Thank you,
> David Wm. Parr
>
> 1. Compiled / Linked gstreamer (0.8.8), gst-plugin (0.8.7), gst-ffmpeg (0.8.3) from source with '-g -O0' to enable debugging information and to disable compiler optimizations.
>    $ CFLAGS='-g -O0' CXXFLAGS=$CFLAGS ./configure
>    $ make
>    $ su
>    # make install
>    # exit
>
> 2. Ran the following command line, specifying as many directories where gdb could find source as I could guess.
>
> gdb --directory /home/dparr/gst/gstreamer-0.8.8/gst \
>     --directory /home/dparr/gst/gstreamer-0.8.8/gst/autoplug \
>     --directory /home/dparr/gst/gstreamer-0.8.8/gst/elements \
>     --directory /home/dparr/gst/gstreamer-0.8.8/gst/indexers \
>     --directory /home/dparr/gst/gstreamer-0.8.8/gst/parse \
>     --directory /home/dparr/gst/gstreamer-0.8.8/gst/schedulers \
>     --directory /home/dparr/gst/gstreamer-0.8.8/gst/registries \
>     --directory /home/dparr/gst/gstreamer-0.8.8/libs/gst/bytestream \
>     --directory /home/dparr/gst/gstreamer-0.8.8/libs/gst/control \
>     --directory /home/dparr/gst/gstreamer-0.8.8/libs/gst/dataprotocol \
>     --directory /home/dparr/gst/gstreamer-0.8.8/libs/gst/getbits \
>     --directory /home/dparr/gst/gstreamer-0.8.8/tools \
>     --directory /home/dparr/gst/gst-plugins-0.8.7/gst/videobox \
>     --args \
>     ./gst-launch filesrc location=~/media.samples/MOV00053.MPG ! \
> 	  mpegdemux name=demux \
> 	  demux.video_00! \
>             mpeg2dec ! \
>             videobox left=-10 right=-10 top=-10 bottom=-10 fill=1 ! \
>             ffcolorspace ! \
>             ximagesink
>
> 3. Obtained the following backtrace (bt)
>
> -----------------------------------------------------
> GDB BACKTRACE
> -----------------------------------------------------
> (gdb) r
> Starting program: /home/dparr/gst/gstreamer-0.8.8/tools/gst-launch filesrc location=/home/dparr/media.samples/MOV00053.MPG \! mpegdemux name=demux demux.video_00\! mpeg2dec \! videobox left=-10 right=-10 top=-10 bottom=-10 fill=1 \! ffcolorspace \! ximagesink
> Detaching after fork from child process 23843.
> Detaching after fork from child process 23845.
> Detaching after fork from child process 23848.
> Detaching after fork from child process 23851.
> Detaching after fork from child process 23852.
> RUNNING pipeline ...
>
> Program received signal SIGSEGV, Segmentation fault.
> 0x4063ade5 in ?? ()
> (gdb) i threads
> (gdb) bt
> #0  0x4063ade5 in ?? ()
> #1  0xfffca27a in ?? ()
> #2  0x0805f768 in ?? ()
> #3  0x401438f0 in globfree64 () from /lib/tls/libc.so.6
> #4  0x40789d80 in ?? ()
> #5  0x0000014a in ?? ()
> #6  0x0002499b in ?? ()
> #7  0xfffcd100 in ?? ()
> #8  0xffffff95 in ?? ()
> #9  0x00000074 in ?? ()
> #10 0x41217dd0 in ?? ()
> #11 0x41217380 in ?? ()
> #12 0x41216b00 in ?? ()
> #13 0x41293000 in ?? ()
> #14 0x4127ebc8 in ?? ()
> #15 0x4126a37c in ?? ()
> #16 0x4126a0e8 in ?? ()
> #17 0x40784584 in ?? ()
> #18 0x00000294 in ?? ()
> #19 0x000001f4 in ?? ()
> #20 0xbfffe538 in ?? ()
> #21 0x4063ce15 in ?? ()
> #22 0x080a1bf8 in ?? ()
> #23 0x080a1bd8 in ?? ()
> #24 0x00000294 in ?? ()
> #25 0x00000004 in ?? ()
> #26 0x08064cc8 in ?? ()
> #27 0x407e7ba4 in ?? ()
> #28 0xbfffe4f8 in ?? ()
> #29 0x407e421b in ?? ()
> #30 0xbfffe4fc in ?? ()
> #31 0x401438f0 in globfree64 () from /lib/tls/libc.so.6
> #32 0x00000001 in ?? ()
> #33 0x08064cc8 in ?? ()
> #34 0x00000001 in ?? ()
> ---Type <return> to continue, or q <return> to quit---q
> Quit
> (gdb)
>
>
>
>
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