Kernel compromise via unvalidated taprio priority map

Improper input validation in Linux and affected Siemens devices allows local users to crash the kernel or execute code via crafted taprio changes. When dev->num_tc is already nonzero, taprio_parse_mqprio_opt returns before validating a supplied priority map, enabling out-of-bounds q->qdiscs access during packet scheduling. Exploitation requires local qdisc configuration privileges, obtainable in an enabled user namespace, and can disclose kernel memory, redirect control flow, or panic the system.