Summary
Software installed and run as a non-privileged user may conduct improper GPU system calls to free memory in still in use, replace with another allocation and cause arbitrary memory reads or writes to physical memory pages. A memory buffer managed by a CPU thread of control (driver) and accessed by a GPU thread of control (firmware) can be freed while in use. Software installed and run as a non-privileged user may replace that buffer with another and replace a shared resource (memory page address list) managed by the CPU thread of control (driver) leading to the GPU accessing memory not managed by the CPU thread of control (driver).