Kernel memory corruption via mismatched debugfs buffer length

Out-of-bounds writes in the Linux kernel allow local users to corrupt kernel memory through crafted AMD GPU debugfs control input. Nine write handlers in amdgpu_dm_debugfs.c pass the user-supplied byte count rather than the allocated buffer size to parse_write_buffer_into_params, allowing the parser to write beyond the heap buffer. Reachability requires local access to writable AMD GPU debugfs controls, which are root-only by default; a successful write compromises kernel confidentiality, integrity, and availability.