Make test passes, but Linux kernel log says "undefined instruction"

Gnu Radio v3.6.4.2 on ARM target.

make test : 100% pass.

But this happens each time python does “from gnuradio import
<6>[ 390.919792] python (1771): undefined instruction: pc=42a9c328
<6>[ 390.919822] Code: 00000000 00000000 f26ee1fe e12fff1e (ee190f1d)

For example, when qa_add_and_friends is started.

This just showed up when switched from Ubuntu 12.04 LTS to 13.04, and
installed new versions of g++, libboost, etc… I went back and checked
my older 12.04 environment which does not exhibit this. My cmake
configuration was the same (except I took out -DENABLE_BAD_BOOST, as I
now have Boost 1.53).

Some version changes:
g++ : 4.6.3-1ubuntu5 to 4.7.3-1ubuntu1
python: 2.7.3 to 2.7.4
swig: 2.0.4 to 2.0.8

If I had not looked at the kernel log, I would not have noticed.
I’ll see if I can narrow this down. But any experience appreciated.