Am Tuesday 22 September 2009 21:13:47 schrieb Pauli Nieminen: > 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.
I'm pretty confident that you can write a perfectly legal OpenGL application that creates commands that take *minutes* to run on decent graphics cards. Just produce a huge number of screen-sized primitives and use a very long fragment program that samples from a huge, non-mipmapped texture in an entirely non-locally-coherent way - and that doesn't even take GLSL loops into account! So this is really not so much about safe-guarding against illegal hardware commands, but about how to deal with the fact that we can't do pre-emptive scheduling on the GPU. In the end, the symptoms are the same, but it might change how you think about the problem. > 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. I have a feeling that this needs a solution that cooperates across the whole stack ... cu, Nicolai ------------------------------------------------------------------------------ Come build with us! The BlackBerry® Developer Conference in SF, CA is the only developer event you need to attend this year. Jumpstart your developing skills, take BlackBerry mobile applications to market and stay ahead of the curve. Join us from November 9-12, 2009. Register now! http://p.sf.net/sfu/devconf -- _______________________________________________ Dri-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/dri-devel
