Local privilege escalation via ignored CPU-write flag

Memory protection bypass in Arm Mali GPU Kernel Driver allows local users to write read-only pages through an imported GPU mapping. The kbase_jd_user_buf_pin_pages function checks only GPU-write permission when pinning imported user pages and ignores the CPU-write flag, so a CPU-writable Mali object can retain a read-only shared page. A local unprivileged process with Mali device access can exploit the mismatched mapping to modify page-cache content and escalate privileges.