[yocto] Debugging shared libraries

Wed Feb 10 12:08:40 PST 2016

> On Feb 10, 2016, at 8:35 AM, Mark Hatle <mark.hatle at windriver.com> wrote:
> 
> On 2/10/16 1:31 AM, Gary Thomas wrote:
>> I'm trying to debug some code (mplayer) which uses some shared
>> libraries from ffmpeg.  When I use GDB (via gdbserver), I don't
>> get all the debug information I need - note that many of the shared
>> libraries do not have any symbolic debugging info:
> 
> Is your system using the the split debug binaries, and if so, do you have them
> all installed on the system that GDB is running on?
> 
> (When GDB starts, you should see it load the symbols, or error it can't find them.)
> 
> Assuming you DO have the symbol files available, and some things are lacking
> debuginfo, it's possible those recipes are not properly building with full
> symbols (they should be, the whole system should be.)
> 
> Easiest way to check is do a readelf/objdump on the .debug version of the
> library and check that there are dwarf symbols present... if not, it's probably
> a recipe error.
> 
> --Mark
> 
>> (gdb) info sharedlibrary
>> From        To          Syms Read   Shared Object Library
>> 0xb6fcf800  0xb6feaf08  Yes         /tmp/p0382.img/lib/ld-linux-armhf.so.3
>> 0xb6fa6fa8  0xb6fb2b40  Yes (*)     /tmp/p0382.img/lib/libtinfo.so.5
>> 0xb6f6d210  0xb6f8c200  Yes         /tmp/p0382.img/usr/lib/libpng16.so.16
>> 0xb6f488e8  0xb6f54a60  Yes         /tmp/p0382.img/lib/libz.so.1
>> 0xb6f069f0  0xb6f34264  Yes         /tmp/p0382.img/usr/lib/libjpeg.so.8
>> 0xb6edbaf0  0xb6eee29c  Yes         /tmp/p0382.img/usr/lib/libdvdread.so.4
>> 0xb6eb6108  0xb6ec7ae8  Yes         /tmp/p0382.img/usr/lib/libass.so.4
>> 0xb6e808b8  0xb6e95384  Yes         /tmp/p0382.img/usr/lib/libvorbis.so.0
>> 0xb6e6b4b4  0xb6e6d7e4  Yes         /tmp/p0382.img/usr/lib/libogg.so.0
>> 0xb6e48978  0xb6e55eb4  Yes         /tmp/p0382.img/usr/lib/libspeex.so.1
>> 0xb6dfe818  0xb6e1b8b4  Yes (*)     /tmp/p0382.img/usr/lib/libfaad.so.2
>> 0xb6d92df0  0xb6dd4e78  Yes (*)     /tmp/p0382.img/usr/lib/libavutil.so.54
>> 0xb5de0640  0xb64a2e18  Yes (*)     /tmp/p0382.img/usr/lib/libavcodec.so.56
>> 0xb5c17528  0xb5d65840  Yes (*)     /tmp/p0382.img/usr/lib/libavformat.so.56
>> 0xb5b81688  0xb5be8db8  Yes (*)     /tmp/p0382.img/usr/lib/libswscale.so.3
>> 0xb5b5f578  0xb5b6c718  Yes (*)     /tmp/p0382.img/usr/lib/libswresample.so.1
>> 0xb5b44998  0xb5b4b490  Yes (*)     /tmp/p0382.img/usr/lib/libpostproc.so.53
>> 0xb5b1f0e0  0xb5b2e194  Yes         /tmp/p0382.img/lib/libpthread.so.0
>> 0xb5aa4c00  0xb5ad46d0  Yes         /tmp/p0382.img/lib/libm.so.6
>> 0xb5a859ec  0xb5a8fc34  Yes         /tmp/p0382.img/usr/lib/libXext.so.6
>> 0xb597b728  0xb59f92bc  Yes         /tmp/p0382.img/usr/lib/libX11.so.6
>> 0xb5946fc8  0xb59573d0  Yes         /tmp/p0382.img/usr/lib/libtheoradec.so.1
>> 0xb5887910  0xb591bbb8  Yes (*)     /tmp/p0382.img/usr/lib/libasound.so.2
>> 0xb58579f8  0xb58586ac  Yes         /tmp/p0382.img/usr/lib/libXss.so.1
>> 0xb5844ca0  0xb5846bac  Yes         /tmp/p0382.img/usr/lib/libXv.so.1
>> 0xb57e7700  0xb58265e0  Yes         /tmp/p0382.img/usr/lib/libSDL-1.2.so.0
>> 0xb56bae00  0xb57abb28  Yes         /tmp/p0382.img/lib/libc.so.6
>> 0xb569292c  0xb5693724  Yes         /tmp/p0382.img/lib/libdl.so.2
>> 0xb5650a70  0xb566e6a4  Yes         /tmp/p0382.img/usr/lib/libfontconfig.so.1
>> 0xb561e324  0xb563951c  Yes         /tmp/p0382.img/usr/lib/libexpat.so.1
>> 0xb559d36c  0xb55f5cb4  Yes         /tmp/p0382.img/usr/lib/libfreetype.so.6
>> 0xb55622b0  0xb5567e84  Yes         /tmp/p0382.img/usr/lib/libenca.so.0
>> 0xb541fbc0  0xb54b5a08  Yes (*)     /tmp/p0382.img/usr/lib/libx264.so.144
>> 0xb53d4df0  0xb53fa0b0  Yes         /tmp/p0382.img/usr/lib/libtheoraenc.so.1
>> 0xb53a72b0  0xb53bd258  Yes (*)     /tmp/p0382.img/usr/lib/liblzma.so.5
>> 0xb5386050  0xb5392cc0  Yes (*)     /tmp/p0382.img/usr/lib/libbz2.so.0
>> 0xb5367810  0xb5373b30  Yes         /tmp/p0382.img/usr/lib/libxcb.so.1
>> 0xb534da00  0xb534e5a8  Yes         /tmp/p0382.img/usr/lib/libXau.so.6
>> 0xb5339f80  0xb533b69c  Yes         /tmp/p0382.img/usr/lib/libXdmcp.so.6
>> 0xb5323720  0xb5326ea0  Yes         /tmp/p0382.img/lib/librt.so.1
>> 0xb530b6e0  0xb5311234  Yes         /tmp/p0382.img/usr/lib/libXrandr.so.2
>> 0xb52f3530  0xb52f9060  Yes         /tmp/p0382.img/usr/lib/libXrender.so.1
>> 0xb52d3160  0xb52e18a4  Yes         /tmp/p0382.img/lib/libgcc_s.so.1
>> (*): Shared library is missing debugging information.
>> 
>> Is this a function of how those libraries were built (by the recipe)
>> or something else?  How can I get the symbolic debugging info enabled?
>> 
>> Thanks for any pointers

Usually it works well if you add

EXTRA_IMAGE_FEATURES_append = “ dbg-pkgs”

image size grows but you get good debug view on target.

another option, I usually use is setup feeds
and then

opkg install <package>-dbg

which pulls in a section of debug info needed to debug a given package.

>> 
> 
> --
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