Messages in this thread | | | Date | Wed, 11 Apr 2018 14:04:47 +0200 | From | Ingo Molnar <> | Subject | Re: perf: fuzzer leads to trace_kprobe: Could not insert message flood |
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* Song Liu <songliubraving@fb.com> wrote:
> > > > On Apr 10, 2018, at 7:48 AM, Vince Weaver <vincent.weaver@maine.edu> wrote: > > > > Author: Song Liu <songliubraving@fb.com> > > 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@fb.com> > > 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. [...]
Vince's point is valid: the kernel log should not be flooded with pointless messages as a response to user-space ABI uses ...
Why is there a kernel log message at all, isn't an error returned?
> [...] I would recommend perf_fuzzer to understand this new API and test it. > [...]
This bug needs to be fixed: a new API must not effectively DoS fuzzing efforts by spamming the kernel log ...
Thanks,
Ingo
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