  Rossby wave instability (RWI) is considered the underlying mechanism to
crescent-shaped azimuthal asymmetries, discovered in (sub-)millimeter dust
continuum of many protoplanetary disks. Previous works on linear theory were
conducted in the hydrodynamic limit. Nevertheless, protoplanetary disks are
likely magnetized and weakly ionized. We examine the influence of magnetic
fields and non-ideal magnetohydrodynamic (MHD) effects - namely, Ohmic
resistivity, Hall drift, and ambipolar diffusion - on the RWI unstable modes.
We perform radially global linear analyses, employing constant azimuthal
($B_\phi$) or vertical ($B_z$) background magnetic fields. It is found that, in
the ideal MHD regime, magnetism can either enhance or diminish RWI growth.
Strong non-ideal MHD effects cause RWI growth rates to recover hydrodynamic
results. The sign of Hall Els\"{a}sser number subtly complicates the results,
and vertical wavenumbers generically diminish growth rates.
