Question

export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/data/usr/lib/

/data/usr/bin/bar&

/data/usr/bin/bar: can't load library 'libfoo.so'

Answer

export LD_LIBRARY_PATH=/data/usr/lib/

or

export LD_LIBRARY_PATH=/data/usr/lib:$LD_LIBRARY_PATH

Before setting LD_LIBRARY_PATH, it is empty, so the final LD_LIBRARY_PATH is :/data/usr/lib/, this is the root cause of this issue.