An apparatus includes a primary processor and a secondary processor configured to receive a first signal, a second signal and a plurality of input signals, and perform same operations as each other based on the first signal, the second signal and the plurality of input signals, a comparison circuit configured to receive output signals of the primary processor and the secondary processor, and detect a lockstep mismatch between the primary processor and the secondary processor based on the output signals, a fault capturing circuit configured to receive the first signal and the second signal, and capture a fault signal generated by the comparison circuit, and a first glitch absorption device configured to receive the first signal and the second signal, and absorb glitches fed into the first glitch absorption device.