perf probe failed to find symbols -

perf probe failed to find symbols -

[Chinnathambi, Muthusamy]

Hi,

I wanted try perf probe, but I am getting the following failure.

[root@force perf_tests]# ./perf probe --add sys_read
Failed to find symbol sys_read in kernel
  Error: Failed to add events.
[root@force perf_tests]#

I had built and installed the kernel with kprobes enabled. Looks like the kernel is stripped, how should I build the kernel for perf to be able to find symbols.

Regards,
Muthusamy C

Re: perf probe failed to find symbols -

[David Ahern]

On 12/15/14 8:18 PM, Chinnathambi, Muthusamy wrote:
> Hi,
>
> I wanted try perf probe, but I am getting the following failure.
>
> [root@force perf_tests]# ./perf probe --add sys_read
> Failed to find symbol sys_read in kernel
>    Error: Failed to add events.

Works for me:
$ perf probe sys_read
Added new event:
   probe:sys_read       (on sys_read)

You can now use it in all perf tools, such as:

	perf record -e probe:sys_read -aR sleep 1

$ uname -r
3.6.11-4.fc16.x86_64

Also, sys_read already has a tracepoint:

   syscalls:sys_enter_read                            [Tracepoint event]
   syscalls:sys_exit_read                             [Tracepoint event]

David

Re: perf probe failed to find symbols -

[Arnaldo Carvalho de Melo]

Em Tue, Dec 16, 2014 at 03:18:24AM +0000, Chinnathambi, Muthusamy escreveu:
> I wanted try perf probe, but I am getting the following failure.
 
> [root@force perf_tests]# ./perf probe --add sys_read
> Failed to find symbol sys_read in kernel
>   Error: Failed to add events.
> [root@force perf_tests]#
 
> I had built and installed the kernel with kprobes enabled. Looks like
> the kernel is stripped, how should I build the kernel for perf to be
> able to find symbols.

In addition to what David said, you can try using -v to get more verbose
error messages that could provide you some extra clue about what is
happening, also please check the other perf probe options, like the one
that lists the available functions to probe (-F), etc.

- Arnaldo