Re: [PATCH] perf buildid-list: Initialize zstd_data

From: Arnaldo Carvalho de Melo
Date: Wed May 12 2021 - 12:42:21 EST


Em Wed, May 12, 2021 at 05:14:29PM +0200, Milian Wolff escreveu:
> On Donnerstag, 29. April 2021 20:57:59 CEST Milian Wolff wrote:
> > Fixes segmentation fault when trying to obtain buildid list (e.g. via
> > perf-archive) from a zstd-compressed `perf.data` file:
>
> Ping, can someone please review and push this upstream? It's such a trivial
> fix, I would like to see it fixed upstream.

Fell thru the cracks, processing it now.

- Arnaldo

> Thanks
>
> > ```
> > $ perf record -z ls
> > ...
> > [ perf record: Captured and wrote 0,010 MB perf.data, compressed
> > (original 0,001 MB, ratio is 2,190) ] $ memcheck perf buildid-list
> > ...
> > ==57268== Invalid read of size 4
> > ==57268== at 0x5260D88: ZSTD_decompressStream (in
> > /usr/lib/libzstd.so.1.4.9) ==57268== by 0x4BB51B: zstd_decompress_stream
> > (zstd.c:100)
> > ==57268== by 0x425C6C: perf_session__process_compressed_event
> > (session.c:73) ==57268== by 0x427450: perf_session__process_user_event
> > (session.c:1631) ==57268== by 0x42A609: reader__process_events
> > (session.c:2207) ==57268== by 0x42A609: __perf_session__process_events
> > (session.c:2264) ==57268== by 0x42A609: perf_session__process_events
> > (session.c:2297) ==57268== by 0x343A62: perf_session__list_build_ids
> > (builtin-buildid-list.c:88) ==57268== by 0x343A62: cmd_buildid_list
> > (builtin-buildid-list.c:120) ==57268== by 0x3C7732: run_builtin
> > (perf.c:313)
> > ==57268== by 0x331157: handle_internal_command (perf.c:365)
> > ==57268== by 0x331157: run_argv (perf.c:409)
> > ==57268== by 0x331157: main (perf.c:539)
> > ==57268== Address 0x7470 is not stack'd, malloc'd or (recently) free'd
> > ```
> >
> > Signed-off-by: Milian Wolff <milian.wolff@xxxxxxxx>
> > ---
> > tools/perf/builtin-buildid-list.c | 3 +++
> > 1 file changed, 3 insertions(+)
> >
> > diff --git a/tools/perf/builtin-buildid-list.c
> > b/tools/perf/builtin-buildid-list.c index 87f5b1a4a7fa..833405c27dae 100644
> > --- a/tools/perf/builtin-buildid-list.c
> > +++ b/tools/perf/builtin-buildid-list.c
> > @@ -80,6 +80,9 @@ static int perf_session__list_build_ids(bool force, bool
> > with_hits) if (!perf_header__has_feat(&session->header, HEADER_BUILD_ID))
> > with_hits = true;
> >
> > + if (zstd_init(&(session->zstd_data), 0) < 0)
> > + pr_warning("Decompression initialization failed. Reported data
> may be
> > incomplete.\n"); +
> > /*
> > * in pipe-mode, the only way to get the buildids is to parse
> > * the record stream. Buildids are stored as RECORD_HEADER_BUILD_ID
>
>
> --
> Milian Wolff | milian.wolff@xxxxxxxx | Senior Software Engineer
> KDAB (Deutschland) GmbH, a KDAB Group company
> Tel: +49-30-521325470
> KDAB - The Qt, C++ and OpenGL Experts



--

- Arnaldo