Lubuntu 16.04 with AMDGPU-PRO Beta Mining Driver 17.40 (October 16th, 2017) installed.
Sapphire Nitro Plus RX 580 8GB. With mining bios mods it was hashing around 29-30Mh/s on Eth for several days (using ethminer from github.com/ethereum-mining/ethminer ). Also XMR at 840-850h/s (using xmr-stak from github.com/fireice-uk/xmr-stak ).
After the security updates for the Meltdown/Spectre/etc vulnerabilities were installed today, the Eth hashrate dropped to 21 Mh/s. XMR at 350h/s. It looks like the mining driver is incompatible with the patched kernel.