Linux kernel bug and horror of C language.

Declaration error a single line only. It would put the vulnerable in the Kernel. Moreover, mistakes that are difficult to discover.
Someone had to say, not enough any number of life If you are using the C/C++ language. It is absolutely correct. In looking at this patch, I've remembered the unpleasant stress when using the C/C++;)

static int perf_swevent_init(struct perf_event *event)
 {
- int event_id = event->attr.config;
+ u64 event_id = event->attr.config;