Re: perf: fuzzer leads to trace_kprobe: Could not insert message flood

[Song Liu]

> On Apr 10, 2018, at 7:48 AM, Vince Weaver <vincent.weaver@xxxxxxxxx> wrote:
> 
> Author: Song Liu <songliubraving@xxxxxx>
> Date:   Wed Dec 6 14:45:15 2017 -0800
> 
> When running the perf_fuzzer on a current git checkout my logs are flooded 
> with messages such as this:
> [71487.869077] trace_kprobe: Could not insert probe at unknown+0: -22
> [71488.174479] trace_kprobe: Could not insert probe at unknown+0: -22
> 
> Presumably this is due to the introduction of the perf_kprobe PMU in
> 	commit e12f03d7031a977356e3d7b75a68c2185ff8d155
> 	Author: Song Liu <songliubraving@xxxxxx>
> 	Date:   Wed Dec 6 14:45:15 2017 -0800
> 
> Is there a way to get this error disabled, or else rate-limited?
> 
> Vince

Hi Vince, 

Thanks for the report. 

This is a new API that creates probe together with perf_event_open(). Based on 
my limited understanding of perf_fuzzer, it doesn't understand this API, and uses 
it in an abnormal way. I would recommend perf_fuzzer to understand this new
API and test it. For more information about using this API, please refer to the 
man-page diff available at:

      https://patchwork.kernel.org/patch/10097283/

Thanks again for the test and report. Please let me know if you have further 
questions. 

Best, 
Song