Re: [PATCH UPDATED] Add support for getting the Kernel symbols from /proc/kallsysm

[Maynard J. <may...@us...>]

On 12/11/2013 12:24 PM, Maynard Johnson wrote:
> On 12/10/2013 02:25 PM, Carl E. Love wrote:
>> Maynard:
>>
>> Sorry, the documentation updates seem to have gotten lost on the first patch, not sure 
>> what happened as I did update the files.  I believe I have also addressed all of your other
>> comments.  Please take a look and see what you think.  Thanks.
> Patch committed, with one small wording change in oprofile.xml (user manual).  Thanks much!
> 
> -Maynard
Carl, I'm sorry to say, but this patch causes two regressions:

1) Segmentation fault when running 'opreport --symbols --debug-info'.

2) On my laptop, I'm seeing incorrect callgraph output when running 'opreport --callgraph' after collecting a callgraph profile with 'operf --callgraph':
-------------------------------------------------------------------------------
  6976     50.0000  memcpyt                  do_my_memcpy
  6976     50.0000  memcpyt                  main
6976      6.2696  memcpyt                  do_my_memcpy
  6976     49.9678  memcpyt                  do_my_memcpy
  6976     49.9678  memcpyt                  do_my_memcpy [self]
  9         0.0645  kallsyms                 /proc/kallsyms
--------------
   Note the last entry -- the symbol name is "/proc/kallsyms".

If I run operf with "--vmlinux" and pass a real vmlinux file, the callgraph entry for "do_my_memcpy" shows up as follows:
-------------------------------------------------------------------------------
  7006     50.0000  memcpyt                  do_my_memcpy
  7006     50.0000  memcpyt                  main
7006      6.3038  memcpyt                  do_my_memcpy
  7006     49.9643  memcpyt                  do_my_memcpy
  7006     49.9643  memcpyt                  do_my_memcpy [self]
  8         0.0571  vmlinux                  apic_timer_interrupt
  2         0.0143  vmlinux                  retint_careful
--------------


I'm sorry I didn't spot these issues sooner.  Can you please take a look?  Thanks!

-Maynard
>>
>>                          Carl Love
>> --------------------------------------------------------------------------------------------
>>
>> Add support for getting the Kernel symbols from /proc/kallsysm
>>
>> This patch reads the /proc/kallsyms file to get the kernel symbols
>> if the user hasn't specified a vmlinux file.
>>
>> Signed-off-by: Carl Love <ca...@us...>
>> ---
>>  doc/operf.1.in                 |    8 +++-
>>  doc/oprofile.xml               |    8 ++-
>>  libperf_events/operf_utils.cpp |   32 +++++++++--
>>  libpp/op_header.cpp            |    8 +++
>>  libpp/populate.cpp             |   22 ++++++--
>>  libutil++/op_bfd.cpp           |  116 ++++++++++++++++++++++++++++++++++++++++
>>  libutil++/op_bfd.h             |   10 ++++
>>  libutil++/utility.h            |    2 +
>>  pe_profiling/operf.cpp         |  112 +++++++++++++++++++++++++++++++++++++-
>>  9 files changed, 303 insertions(+), 15 deletions(-)
>>
> [snip]