Either your kernel is patched, or the exploit does not work on your system. It certainly fails without -O2, glance over the code indicates horrible reliance on

Either your kernel is patched, or the exploit does not work on your system. It certainly fails without -O2, glance over the code indicates horrible reliance on various UB on how gcc compiles it. $ grep -A 10 'int perf_swevent_init' linux-2.6.32-358.el6/kernel/events/core.c static int perf_swevent_init(struct perf_event *event) { int event_id = event->attr.config; if (event->attr.type != PERF_TYPE_SOFTWARE) return -ENOENT; switch (event_id) { case PERF_COUNT_SW_CPU_CLOCK: case PERF_COUNT_SW_TASK_CLOCK: return -ENOENT;