preventing GPU reset DoS

[Pauli N. <su...@gm...>]

Hi!

I have been thinking GPU reset as possible DoS attack from
user-space.Problem here is that display doesn't work anymore at all if
attacker chooses to run a application that constantly causes GPU hang. It
would be of course ideal to have CS checker not to let in any problematic
combinations of commands. Butin practice we can't assume that everything is
safe with all hardware so we need to take some actions prevent possible
problems.

So first defense would be terminating application that did send command
stream that caused GPU hang. But attacker could easily by-pass this
protection with forking all the time new processes.

So we need stronger defense if same user account is causing multiple hangs
in short time frame. I would think temporary denying new DRI access would
let user to gain back control of system and take actions to stop the
problematic program from running.

Pauli