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References: <20210624231926.212208-1-rickyman7@gmail.com>
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From:   Ian Rogers <irogers@google.com>
Date:   Thu, 24 Jun 2021 22:39:34 -0700
Message-ID: <CAP-5=fVbGZbV3qp27DPD_7r0z-v9hr2m34H294angaEsssKB0Q@mail.gmail.com>
Subject: Re: [PATCH v2] perf session: add missing evlist__delete when deleting
 a session
To:     Riccardo Mancini <rickyman7@gmail.com>
Cc:     Arnaldo Carvalho de Melo <acme@kernel.org>,
        Namhyung Kim <namhyung@kernel.org>,
        Peter Zijlstra <peterz@infradead.org>,
        Ingo Molnar <mingo@redhat.com>,
        Mark Rutland <mark.rutland@arm.com>,
        Alexander Shishkin <alexander.shishkin@linux.intel.com>,
        Jiri Olsa <jolsa@redhat.com>,
        Adrian Hunter <adrian.hunter@intel.com>,
        Kan Liang <kan.liang@linux.intel.com>,
        Leo Yan <leo.yan@linaro.org>, linux-perf-users@vger.kernel.org,
        linux-kernel@vger.kernel.org
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On Thu, Jun 24, 2021 at 4:20 PM Riccardo Mancini <rickyman7@gmail.com> wrote:
>
> ASan reports a memory leak caused by evlist not being deleted on exit in
> perf-report, perf-script and perf-data.
> The problem is caused by evlist->session not being deleted, which is
> allocated in perf_session__read_header, called in perf_session__new if
> perf_data is in read mode.
> In case of write mode, the session->evlist is filled by the caller.
> This patch solves the problem by calling evlist__delete in
> perf_session__delete if perf_data is in read mode.

Acked-by: Ian Rogers <irogers@google.com>

It is messy that in read mode the session owns the evlist, but
otherwise not. Imo, it'd be nice to make the ownership unconditional.

Thanks,
Ian

> Changes in v2:
>  - call evlist__delete from within perf_session__delete
>
> v1: https://lore.kernel.org/lkml/20210621234317.235545-1-rickyman7@gmail.com/
>
> ASan report follows:
>
> $ ./perf script report flamegraph
> =================================================================
> ==227640==ERROR: LeakSanitizer: detected memory leaks
>
> <SNIP unrelated>
>
> Indirect leak of 2704 byte(s) in 1 object(s) allocated from:
>     #0 0x4f4137 in calloc (/home/user/linux/tools/perf/perf+0x4f4137)
>     #1 0xbe3d56 in zalloc /home/user/linux/tools/lib/perf/../../lib/zalloc.c:8:9
>     #2 0x7f999e in evlist__new /home/user/linux/tools/perf/util/evlist.c:77:26
>     #3 0x8ad938 in perf_session__read_header /home/user/linux/tools/perf/util/header.c:3797:20
>     #4 0x8ec714 in perf_session__open /home/user/linux/tools/perf/util/session.c:109:6
>     #5 0x8ebe83 in perf_session__new /home/user/linux/tools/perf/util/session.c:213:10
>     #6 0x60c6de in cmd_script /home/user/linux/tools/perf/builtin-script.c:3856:12
>     #7 0x7b2930 in run_builtin /home/user/linux/tools/perf/perf.c:313:11
>     #8 0x7b120f in handle_internal_command /home/user/linux/tools/perf/perf.c:365:8
>     #9 0x7b2493 in run_argv /home/user/linux/tools/perf/perf.c:409:2
>     #10 0x7b0c89 in main /home/user/linux/tools/perf/perf.c:539:3
>     #11 0x7f5260654b74  (/lib64/libc.so.6+0x27b74)
>
> Indirect leak of 568 byte(s) in 1 object(s) allocated from:
>     #0 0x4f4137 in calloc (/home/user/linux/tools/perf/perf+0x4f4137)
>     #1 0xbe3d56 in zalloc /home/user/linux/tools/lib/perf/../../lib/zalloc.c:8:9
>     #2 0x80ce88 in evsel__new_idx /home/user/linux/tools/perf/util/evsel.c:268:24
>     #3 0x8aed93 in evsel__new /home/user/linux/tools/perf/util/evsel.h:210:9
>     #4 0x8ae07e in perf_session__read_header /home/user/linux/tools/perf/util/header.c:3853:11
>     #5 0x8ec714 in perf_session__open /home/user/linux/tools/perf/util/session.c:109:6
>     #6 0x8ebe83 in perf_session__new /home/user/linux/tools/perf/util/session.c:213:10
>     #7 0x60c6de in cmd_script /home/user/linux/tools/perf/builtin-script.c:3856:12
>     #8 0x7b2930 in run_builtin /home/user/linux/tools/perf/perf.c:313:11
>     #9 0x7b120f in handle_internal_command /home/user/linux/tools/perf/perf.c:365:8
>     #10 0x7b2493 in run_argv /home/user/linux/tools/perf/perf.c:409:2
>     #11 0x7b0c89 in main /home/user/linux/tools/perf/perf.c:539:3
>     #12 0x7f5260654b74  (/lib64/libc.so.6+0x27b74)
>
> Indirect leak of 264 byte(s) in 1 object(s) allocated from:
>     #0 0x4f4137 in calloc (/home/user/linux/tools/perf/perf+0x4f4137)
>     #1 0xbe3d56 in zalloc /home/user/linux/tools/lib/perf/../../lib/zalloc.c:8:9
>     #2 0xbe3e70 in xyarray__new /home/user/linux/tools/lib/perf/xyarray.c:10:23
>     #3 0xbd7754 in perf_evsel__alloc_id /home/user/linux/tools/lib/perf/evsel.c:361:21
>     #4 0x8ae201 in perf_session__read_header /home/user/linux/tools/perf/util/header.c:3871:7
>     #5 0x8ec714 in perf_session__open /home/user/linux/tools/perf/util/session.c:109:6
>     #6 0x8ebe83 in perf_session__new /home/user/linux/tools/perf/util/session.c:213:10
>     #7 0x60c6de in cmd_script /home/user/linux/tools/perf/builtin-script.c:3856:12
>     #8 0x7b2930 in run_builtin /home/user/linux/tools/perf/perf.c:313:11
>     #9 0x7b120f in handle_internal_command /home/user/linux/tools/perf/perf.c:365:8
>     #10 0x7b2493 in run_argv /home/user/linux/tools/perf/perf.c:409:2
>     #11 0x7b0c89 in main /home/user/linux/tools/perf/perf.c:539:3
>     #12 0x7f5260654b74  (/lib64/libc.so.6+0x27b74)
>
> Indirect leak of 32 byte(s) in 1 object(s) allocated from:
>     #0 0x4f4137 in calloc (/home/user/linux/tools/perf/perf+0x4f4137)
>     #1 0xbe3d56 in zalloc /home/user/linux/tools/lib/perf/../../lib/zalloc.c:8:9
>     #2 0xbd77e0 in perf_evsel__alloc_id /home/user/linux/tools/lib/perf/evsel.c:365:14
>     #3 0x8ae201 in perf_session__read_header /home/user/linux/tools/perf/util/header.c:3871:7
>     #4 0x8ec714 in perf_session__open /home/user/linux/tools/perf/util/session.c:109:6
>     #5 0x8ebe83 in perf_session__new /home/user/linux/tools/perf/util/session.c:213:10
>     #6 0x60c6de in cmd_script /home/user/linux/tools/perf/builtin-script.c:3856:12
>     #7 0x7b2930 in run_builtin /home/user/linux/tools/perf/perf.c:313:11
>     #8 0x7b120f in handle_internal_command /home/user/linux/tools/perf/perf.c:365:8
>     #9 0x7b2493 in run_argv /home/user/linux/tools/perf/perf.c:409:2
>     #10 0x7b0c89 in main /home/user/linux/tools/perf/perf.c:539:3
>     #11 0x7f5260654b74  (/lib64/libc.so.6+0x27b74)
>
> Indirect leak of 7 byte(s) in 1 object(s) allocated from:
>     #0 0x4b8207 in strdup (/home/user/linux/tools/perf/perf+0x4b8207)
>     #1 0x8b4459 in evlist__set_event_name /home/user/linux/tools/perf/util/header.c:2292:16
>     #2 0x89d862 in process_event_desc /home/user/linux/tools/perf/util/header.c:2313:3
>     #3 0x8af319 in perf_file_section__process /home/user/linux/tools/perf/util/header.c:3651:9
>     #4 0x8aa6e9 in perf_header__process_sections /home/user/linux/tools/perf/util/header.c:3427:9
>     #5 0x8ae3e7 in perf_session__read_header /home/user/linux/tools/perf/util/header.c:3886:2
>     #6 0x8ec714 in perf_session__open /home/user/linux/tools/perf/util/session.c:109:6
>     #7 0x8ebe83 in perf_session__new /home/user/linux/tools/perf/util/session.c:213:10
>     #8 0x60c6de in cmd_script /home/user/linux/tools/perf/builtin-script.c:3856:12
>     #9 0x7b2930 in run_builtin /home/user/linux/tools/perf/perf.c:313:11
>     #10 0x7b120f in handle_internal_command /home/user/linux/tools/perf/perf.c:365:8
>     #11 0x7b2493 in run_argv /home/user/linux/tools/perf/perf.c:409:2
>     #12 0x7b0c89 in main /home/user/linux/tools/perf/perf.c:539:3
>     #13 0x7f5260654b74  (/lib64/libc.so.6+0x27b74)
>
> SUMMARY: AddressSanitizer: 3728 byte(s) leaked in 7 allocation(s).
>
> Signed-off-by: Riccardo Mancini <rickyman7@gmail.com>
> ---
>  tools/perf/util/session.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c
> index e59242c361ce..c36464d94387 100644
> --- a/tools/perf/util/session.c
> +++ b/tools/perf/util/session.c
> @@ -301,8 +301,11 @@ void perf_session__delete(struct perf_session *session)
>         perf_session__release_decomp_events(session);
>         perf_env__exit(&session->header.env);
>         machines__exit(&session->machines);
> -       if (session->data)
> +       if (session->data) {
> +               if (perf_data__is_read(session->data))
> +                       evlist__delete(session->evlist);
>                 perf_data__close(session->data);
> +       }
>         free(session);
>  }
>
> --
> 2.31.1
>