linking error when building shared library

Hi,

compiling my library with

ifort -O3 -mkl=sequential -warn nounused -warn declarations -fPIC -c *.f90

and subsequently linking with

ifort -shared -Wl,-soname,tmp.so -o tmp.so *.o

yields

ld: tmp.so: version node not found for symbol mod_Test_20160424_single@sort._
ld: failed to set dynamic section sizes: Bad value

The Subroutine "sort" is located in a submodule SubMod_Test_20160424_Single_Sort.f90 of which parent module is Mod_Test_20160424_Single.f90.

Any idea what the problem is??

Thanks

Karl