Re: OOPS in perf_mmap_close()

From: Vince Weaver
Date: Thu May 30 2013 - 08:46:34 EST


On Thu, 30 May 2013, Peter Zijlstra wrote:
>
> Awesome! How specific is it to perf? I mean, would that tool work
> equally well for other tinity report?

No, it's fairly specific to my perf_fuzzer. I only use trinity code to
set up the perf_event_open() attr parameters, everything else I use my own
code for.

The logging output from perf_fuzzer is fairly straightforward. Just a
single char indicating which syscall and a space separated list of
the result (if relevant) and then all the syscall parameters.

The logging output can then be used by both the replayer and the
sample-code generator.

While in theory this could be extended to something generic, currently it
only works for perf_event_open/close/ioctl/read/write/mmap/munmap, and
even then it takes some shortcuts because I know it will only be run when
finding perf_event problems.

The code for all of this is here if anyone else wants to play with it.
https://github.com/deater/perf_event_tests/tree/master/fuzzer

> I'll go prod, thanks again!

The bug looks related to hw breakpoints, not sure if the bugs Oleg
Nesterov has been reporting in this area might be relevant or not.

Vince
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