Local privilege escalation via misaligned uprobe offsets

Improper input validation in Linux kernel uprobes from 5.8 allows local users with CAP_PERFMON to gain root or interrupt the system. The perf uprobe registration path validates only that an instruction can be decoded at an attacker-selected offset, not that the offset begins an instruction in the executed stream. A crafted mid-instruction or text-data probe can corrupt existing process mappings without victim interaction, enabling root code execution or a system-wide crash.