Kernel memory corruption via paired-job use-after-free

Use-after-free in the Linux kernel PowerVR DRM driver allows local users to corrupt kernel memory through paired GPU jobs. The fragment job fails to retain a reference to its paired geometry job, so the scheduler's pvr_queue_prepare_job path reads the geometry structure after it is freed. Access to a system using the affected driver and paired geometry and fragment jobs is required; successful triggering compromises kernel memory integrity and can interrupt the system.