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

[David Parr]

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)