  We consider position-dependent mass (PDM) Klein-Gordon (KG) particles in
cosmic string rainbow gravity spacetime in a non-uniform magnetic field. The
corresponding KG-equation is reduced into the one-dimensional form of the
two-dimensional radial Schr\"{o}dinger-oscillator like equation (hence the
notion KG-oscillator). We first report on the effects of rainbow gravity on the
energy levels of KG-oscillators with constant mass. Next, we include the PDM
settings so that KG-oscillators like interaction are introduced. The effects of
PDM on the spectra of KG-oscillators in cosmic string rainbow gravity spacetime
are also reported. In both cases four pairs of rainbow functions are
considered: (a) $% g_{_{0}}\left( y\right) =1$, $g_{_{1}}\left( y\right)
=\sqrt{1-\epsilon y^{2}% }$, (b) $g_{_{0}}\left( y\right) =1$, $g_{_{1}}\left(
y\right) =\sqrt{% 1-\epsilon y}$, (c) $g_{_{0}}\left( y\right) =g_{_{1}}\left(
y\right) =\left( 1-\epsilon y\right) ^{-1}$, and (d) $g_{_{0}}\left( y\right)
=\left( e^{\epsilon y}-1\right) /\epsilon y$, $g_{_{1}}\left( y\right) =1$,
where $y=E/E_p$ and $\epsilon$ is the rainbow parameter. We report that, as
long as KG-particles are in point, the rainbow functions pair in (a) is the
only pair to emphasis that the Planck energy is the maximum possible energy the
KG-particles may have.
