  The energy levels of the fermions bound to the vortex are considered for
vortices in the superfluid/superconducting systems which contain the symmetry
protected plane of zeroes in the gap function in bulk. The Caroli-de
Gennes-Matricon branches with different angular momentum quantum number $n$
approach zero energy level at $p_z\rightarrow 0$. Such condensation of the
energy levels is the consequence of the bulk-vortex correspondence in
topological superfluids/superconductors. In a given case this is the connection
between the Dirac line of zeroes in the bulk spectrum and the level
condensation in the vortex core. The density of states of the bound fermions
diverges at zero energy giving rise to the $\sqrt{\Omega}$ dependence of DoS in
the polar phase of superfluid $^3$He rotating with the angular velocity
$\Omega$ and to the $\sqrt{B}$ dependence of DoS for superconductors in the
$(d_{xz} + i d_{yz})$-wave pairing state.
