  In this paper, we investigate unexplored aspects of scheduler contention: We
systematically study the leakage of all scheduler queues on AMD Zen 3 and show
that all queues leak. We mount the first scheduler contention attacks on Zen 4,
with a novel measurement method evoking an out-of-order race condition, more
precise than the state of the art. We demonstrate the first inter-keystroke
timing attacks based on scheduler contention, with an F1 score of $\geq$ 99.5 %
and a standard deviation below 4 ms from the ground truth. Our end-to-end
JavaScript attack transmits across Firefox instances, bypassing cross-origin
policies and site isolation, with 891.9 bit/s (Zen 3) and 940.7 bit/s (Zen 4).
