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Add an ioctl if you need to be able to retrieve >>> that info. >> >> Yeah the problem is an IOCTL is even worse from the security pov. >> >> This is for an tool which doesn't have access to the file descriptor which provides that information. >> >> So using pidfd_getfd() or similar to get the FD and then call an IOCTL on it would be a security violation. >> >> The real question is how should we make this information public available in the system? > > Don't you have a way to make this info available in sysfs? Just like > networking exposes info about network devices in there that may come and > go? Yeah that was already tried as well and Greg summarized it as "sometimes you don't know how horrible something is until you tried it". So the memory accounting parts for DMA-buf files in sysfs were deprecated and removed again just a few weeks ago. And that was basically just a subset of what David tries to do here. The requirement is that you want to be able to access the stats for accelerators/GPUs drivers similar to how tools like "top" or "htop" work. E.g. everybody can access /proc/*/stat as well, it's just that some security related information are left out. As far as I can see we have only a couple of different options to fulfill that requirement and lowering the security for fdinfo like David's patch here suggests still looks like the most defensive one to me. Regards, Christian.