kernel/trace/latency_hist.c
   373  static ssize_t
   374  latency_hist_show_maxlatproc(struct file *filp, char __user *ubuf,
   375                        size_t cnt, loff_t *ppos)
   376  {
   377          char buf[1024];

This is a large buffer to put on the stack.

regards,
dan carpenter