Can not get the filename by example/bcc/perf

[guozijing]

When i run go run example/bcc/perf/perf.go,
I can capture the syscall_chown, but i can not get the right uid, pid and filename.

---

strace -e trace=fchownat chown root:admin ./install.sh

fchownat(AT_FDCWD, "./install.sh", 0, 1000, 0) = 0
+++ exited with 0 +++

go run perf.go

uid 4294967295 gid 0 pid 1436932 called fchownat(2) on (return value: 0)
uid 4294967295 gid 0 pid 1437344 called fchownat(2) on (return value: 0)