perf test vfs_getname failed

[Li Zhijian <zhijianx.li@intel.com>]

Hi Arnaldo

i encounter some problem when running perf test, the details arelike below:

-----------------------------

[lizj@rhel71 perf]$ sudo ./perf test vfs_getname -v
61: Add vfs_getname probe to get syscall args filenames   :
--- start ---
test child forked, pid 5958
Failed to find 'result' in this function.
   Error: Failed to add events.
test child finished with -1
---- end ----
Add vfs_getname probe to get syscall args filenames: FAILED!
62: Use vfs_getname probe to get syscall args filenames   :
--- start ---
test child forked, pid 5979
Failed to find 'result' in this function.
   Error: Failed to add events.
test child finished with -1
---- end ----
Use vfs_getname probe to get syscall args filenames: FAILED!
63: Check open filename arg using perf trace + vfs_getname:
--- start ---
test child forked, pid 6001
Failed to find 'result' in this function.
   Error: Failed to add events.
test child finished with -1
---- end ----
Check open filename arg using perf trace + vfs_getname: FAILED!
-----------------------------

my environment:
1. perf features
the enabled features are:
-----------------------------

Auto-detecting system features:
...                         dwarf: [ on  ]
...            dwarf_getlocations: [ on  ]
...                         glibc: [ on  ]
...                          gtk2: [ on  ]
...                      libaudit: [ on  ]
...                        libbfd: [ on  ]
...                        libelf: [ on  ]
...                       libnuma: [ on  ]
...        numa_num_possible_cpus: [ on  ]
...                       libperl: [ on  ]
...                     libpython: [ on  ]
...                      libslang: [ OFF ]
...                     libcrypto: [ on  ]
...                     libunwind: [ on  ]
...            libdw-dwarf-unwind: [ on  ]
...                          zlib: [ on  ]
...                          lzma: [ on  ]
...                     get_cpuid: [ on  ]
...                           bpf: [ on  ]
-----------------------------
2. host
[lizj@rhel71 perf]$ cat /etc/redhat-release
Red Hat Enterprise Linux Server release 7.1 Beta (Maipo)

3. kernel
[lizj@rhel71 perf]$ uname -a
Linux rhel71 4.14.0-rc1+ #2 SMP Wed Oct 18 23:49:30 EDT 2017 x86_64 x86_64 x86_64 GNU/Linux

if i miss something, fell free to let me know :)

Thanks

Zhijian