>> While playing with GPU programming, I had a lot of such freeze, and they >> never locked the CPU. I was always able to connect to my machine though SSH.
Sometimes you can, sometimes you can't. It depends on exactly how things fail. > So a regular user process can permanently lock up the display, requiring a > reboot, just by executing some bad GPU code?! That’s kind of a bad privilege > violation and could be considered a DoS exploit. Yes, it is. A particularly serious one. It's been a pet peeve of mine for years that this is knowingly ignored by those who should know better. Last I checked, there was a watchdog mechanism on the GPU that would fire after some time (7 seconds on nVidia GPUs). That signals the driver (on the CPU) that it's doing a watchdog reset. Unfortunately, the drivers don't really handle that. They could - and *should* - reinitialise and recover, but it's just not implemented (or at least wasn't, a year or two ago). [[ There's probably also timeouts implemented in the driver and various other layers, though I don't know the details. ]] If you've ever done any CUDA work you'll be all too familiar with this problem. Much of nVidia's own example code will trigger this failure mode, and most require a reboot to recover from. In general GPUs are in a comparative stone-age when it comes to security and stability. They're getting better - retracing the steps of CPUs thirty years ago while thinking they're being very clever, in a cutely naive way - but it'll probably be many years before these problems are properly resolved. AMD & Intel are significantly ahead of nVidia in this regard, I hear. But personally, after having every single nVidia-packing machine I've ever owned die (sometimes repeatedly) due to GPU-related hardware faults, I'd never buy an nVidia based machine to begin with. But I digress... back to trying to recover data from my 8800GS iMac... again... _______________________________________________ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
