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From:   SeongJae Park <sj@kernel.org>
To:     Namhyung Kim <namhyung@kernel.org>
Cc:     SeongJae Park <sj@kernel.org>,
        Sumanth Korikkar <sumanthk@linux.ibm.com>, olsajiri@gmail.com,
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Subject: Re: [PATCH] bpf: fix sample_flags for bpf_perf_event_output
Date:   Mon, 17 Oct 2022 23:35:44 +0000
Message-Id: <20221017233544.1408-1-sj@kernel.org>
In-Reply-To: <CAM9d7cj1cvg6JUp33qxew59qz1_4hEu8noa-E3oO9DXFHabGaw@mail.gmail.com>
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On Mon, 17 Oct 2022 15:52:15 -0700 Namhyung Kim <namhyung@kernel.org> wrote:

> Hi SeongJae,
> 
> On Mon, Oct 17, 2022 at 12:27 PM SeongJae Park <sj@kernel.org> wrote:
> >
> > Hello,
> >
> >
> > The commit that this patch is fixing[1] also causes yet another segfault for
> > 'perf-script' of tracepoint records.  For example:
> >
> >     $ sudo timeout 3 perf record -e exceptions:page_fault_user
> >     [ perf record: Woken up 1 times to write data ]
> >     [ perf record: Captured and wrote 0.228 MB perf.data (74 samples) ]
> >     $ sudo perf script
> >     Segmentation fault
> >
> > Reverting this patch and the original bug commit[1] fixes the issue.  I haven't
> > deep dive yet because I'm not familiar with this area.  Anybody has any idea
> > about this?
> >
> > [1] 838d9bb62d13 ("perf: Use sample_flags for raw_data")
> 
> Sorry for the trouble.

No problem.

> I think you also need to apply the below:
> 
> https://lore.kernel.org/r/20221012143857.48198-1-james.clark@arm.com

Thank you for this nice answer.  I confirmed that this fixes my issue.


Thanks,
SJ

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