Regular black holes with stable cores

Non-singular black hole geometries typically come with two spacetime horizons: an (outer) event horizon and (inner) Cauchy horizon. This nurtures the speculation that they may be subject to a mass-inflation effect which renders unstable. We analyze dynamics associated spherically symmetric, regular holes taking full backreaction between infalling matter geometry into account. On this basis, we identify crucial features taming growth of mass function diminishing curvature singularity at It is demonstrated explicitly solutions proposed by Hayward obtained from Asymptotic Safety satisfy these properties.