What do these warnings mean?

What do these warnings mean?

[Gary Thomas]

I imported libav from meta-oe into my build so I can have additional
gstreamer support.  Now I'm seeing these warnings:

WARNING: QA Issue: ELF binary 
'/home/local/p82_soft/tmp/work/cortexa9-vfp-neon-amltd-linux-gnueabi/gst-plugins-bad/0.10.23-r3.ti1.6.4.3/packages-split/gst-plugins-bad-vp8/usr/lib/gstreamer-0.10/libgstvp8.so' 
has relocations in .text
WARNING: QA Issue: ELF binary '/home/local/p82_soft/tmp/work/cortexa9-vfp-neon-amltd-linux-gnueabi/libav/0.8.3-r0/packages-split/libavcodec/usr/lib/libavcodec.so.53.35.0' has 
relocations in .text

Exactly what do these mean?  What do I do to get rid of them?

Thanks

-- 
------------------------------------------------------------
Gary Thomas                 |  Consulting for the
MLB Associates              |    Embedded world
------------------------------------------------------------

Re: What do these warnings mean?

[Richard Purdie]

On Thu, 2013-02-14 at 05:35 -0700, Gary Thomas wrote:
> I imported libav from meta-oe into my build so I can have additional
> gstreamer support.  Now I'm seeing these warnings:
> 
> WARNING: QA Issue: ELF binary 
> '/home/local/p82_soft/tmp/work/cortexa9-vfp-neon-amltd-linux-gnueabi/gst-plugins-bad/0.10.23-r3.ti1.6.4.3/packages-split/gst-plugins-bad-vp8/usr/lib/gstreamer-0.10/libgstvp8.so' 
> has relocations in .text
> WARNING: QA Issue: ELF binary '/home/local/p82_soft/tmp/work/cortexa9-vfp-neon-amltd-linux-gnueabi/libav/0.8.3-r0/packages-split/libavcodec/usr/lib/libavcodec.so.53.35.0' has 
> relocations in .text
> 
> Exactly what do these mean?  What do I do to get rid of them?

It means the linker has to perform relocations on the .text segment at
runtime. This slows down loads and means more memory usage if two
applications use the library since the kernel can't share the mappings.
It will work its just inefficient.

The fix us usually to compile as position independent code using the pic
compiler option.

Cheers,

Richard (far from an expert on this)

Re: What do these warnings mean?

[Phil Blundell]

On Thu, 2013-02-14 at 05:35 -0700, Gary Thomas wrote:
> WARNING: QA Issue: ELF binary 
> '/home/local/p82_soft/tmp/work/cortexa9-vfp-neon-amltd-linux-gnueabi/gst-plugins-bad/0.10.23-r3.ti1.6.4.3/packages-split/gst-plugins-bad-vp8/usr/lib/gstreamer-0.10/libgstvp8.so' 
> has relocations in .text
> WARNING: QA Issue: ELF binary '/home/local/p82_soft/tmp/work/cortexa9-vfp-neon-amltd-linux-gnueabi/libav/0.8.3-r0/packages-split/libavcodec/usr/lib/libavcodec.so.53.35.0' has 
> relocations in .text
> 
> Exactly what do these mean?  What do I do to get rid of them?

Generally they mean that some non-PIC code has leaked into a shared
library.  The most common way for that to happen is for a DSO final link
to accidentally pull in some members from a static library.  There are a
few other possible causes as well, mostly toolchain bugs or limitations
(you used to get this under some circumstances when enabling full unwind
tables on MIPS for example), but non-PIC code is the most likely one.

You can use readelf or objdump to inspect the relocation table for the
files in question.  In most cases there is a fairly obvious culprit,
e.g. an R_ARM_PC24 reloc with an incriminating function name. 

Having relocations in .text is undesirable because it wastes memory and
slows down program startup.  They can occasionally cause more severe
problems: for example, if were using SELinux then you might find that
your security policy didn't allow those binaries to be run at all.
(This was the default policy on Fedora for a while; I've no idea if it
still is.)

p.