Now and again perf is failing to build.  It looks like these appeared with the recent kernel upgrade in master.

  GEN      TOPDIR/tmp/work/qemuppc-poky-linux/perf/1.0-r9/perf-1.0/common-cmds.h
  HOSTCC   TOPDIR/tmp/work/qemuppc-poky-linux/perf/1.0-r9/perf-1.0/fixdep.o
  HOSTLD   TOPDIR/tmp/work/qemuppc-poky-linux/perf/1.0-r9/perf-1.0/fixdep-in.o
  LINK     TOPDIR/tmp/work/qemuppc-poky-linux/perf/1.0-r9/perf-1.0/fixdep
  MKDIR    TOPDIR/tmp/work/qemuppc-poky-linux/perf/1.0-r9/perf-1.0/pmu-events/
  MKDIR    TOPDIR/tmp/work/qemuppc-poky-linux/perf/1.0-r9/perf-1.0/pmu-events/
  HOSTCC   TOPDIR/tmp/work/qemuppc-poky-linux/perf/1.0-r9/perf-1.0/pmu-events/jevents.o
  HOSTCC   TOPDIR/tmp/work/qemuppc-poky-linux/perf/1.0-r9/perf-1.0/pmu-events/json.o
  HOSTCC   TOPDIR/tmp/work/qemuppc-poky-linux/perf/1.0-r9/perf-1.0/pmu-events/jsmn.o
/bin/sh: TOPDIR/tmp/work/qemuppc-poky-linux/perf/1.0-r9/perf-1.0//fixdep: Permission denied

(http://errors.yoctoproject.org/Errors/Details/158286/ has more context)

My guess is its trying to use fixdep whilst the binary is still being linked.  Should be an easy fix but the kernel makefiles are a maze!