linux-kernel - Re: [PATCH 8/9] perf test: Free aliases for PMU event map aliases test

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Message-ID: <CAM9d7ci=knY_Wu8vbdfOzCtJX_onciz2eri8E=d2KM2qwG6QGQ@mail.gmail.com>
Date:   Mon, 7 Sep 2020 22:20:34 +0900
From:   Namhyung Kim <namhyung@...nel.org>
To:     John Garry <john.garry@...wei.com>
Cc:     Arnaldo Carvalho de Melo <acme@...nel.org>,
        Jiri Olsa <jolsa@...hat.com>, Ingo Molnar <mingo@...nel.org>,
        Peter Zijlstra <a.p.zijlstra@...llo.nl>,
        Mark Rutland <mark.rutland@....com>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Stephane Eranian <eranian@...gle.com>,
        LKML <linux-kernel@...r.kernel.org>,
        Andi Kleen <andi@...stfloor.org>,
        Ian Rogers <irogers@...gle.com>
Subject: Re: [PATCH 8/9] perf test: Free aliases for PMU event map aliases test

Hello,

On Mon, Sep 7, 2020 at 7:31 PM John Garry <john.garry@...wei.com> wrote:
>
> On 07/09/2020 04:45, Namhyung Kim wrote:
> > The aliases were never released causing the following leaks:
> >
> >    Indirect leak of 1224 byte(s) in 9 object(s) allocated from:
> >      #0 0x7feefb830628 in malloc (/lib/x86_64-linux-gnu/libasan.so.5+0x107628)
> >      #1 0x56332c8f1b62 in __perf_pmu__new_alias util/pmu.c:322
> >      #2 0x56332c8f401f in pmu_add_cpu_aliases_map util/pmu.c:778
> >      #3 0x56332c792ce9 in __test__pmu_event_aliases tests/pmu-events.c:295
> >      #4 0x56332c792ce9 in test_aliases tests/pmu-events.c:367
> >      #5 0x56332c76a09b in run_test tests/builtin-test.c:410
> >      #6 0x56332c76a09b in test_and_print tests/builtin-test.c:440
> >      #7 0x56332c76ce69 in __cmd_test tests/builtin-test.c:695
> >      #8 0x56332c76ce69 in cmd_test tests/builtin-test.c:807
> >      #9 0x56332c7d2214 in run_builtin /home/namhyung/project/linux/tools/perf/perf.c:312
> >      #10 0x56332c6701a8 in handle_internal_command /home/namhyung/project/linux/tools/perf/perf.c:364
> >      #11 0x56332c6701a8 in run_argv /home/namhyung/project/linux/tools/perf/perf.c:408
> >      #12 0x56332c6701a8 in main /home/namhyung/project/linux/tools/perf/perf.c:538
> >      #13 0x7feefb359cc9 in __libc_start_main ../csu/libc-start.c:308
> >
> > Cc: John Garry <john.garry@...wei.com>
> > Fixes: 956a78356c24c ("perf test: Test pmu-events aliases")
> > Signed-off-by: Namhyung Kim <namhyung@...nel.org>
> > ---
> >   tools/perf/tests/pmu-events.c | 5 +++++
> >   tools/perf/util/pmu.c         | 2 +-
> >   tools/perf/util/pmu.h         | 1 +
> >   3 files changed, 7 insertions(+), 1 deletion(-)
> >
> > diff --git a/tools/perf/tests/pmu-events.c b/tools/perf/tests/pmu-events.c
> > index eb19f9a0bc15..d3517a74d95e 100644
> > --- a/tools/perf/tests/pmu-events.c
> > +++ b/tools/perf/tests/pmu-events.c
> > @@ -274,6 +274,7 @@ static int __test__pmu_event_aliases(char *pmu_name, int *count)
> >       int res = 0;
> >       bool use_uncore_table;
> >       struct pmu_events_map *map = __test_pmu_get_events_map();
> > +     struct perf_pmu_alias *a, *tmp;
> >
> >       if (!map)
> >               return -1;
> > @@ -347,6 +348,10 @@ static int __test__pmu_event_aliases(char *pmu_name, int *count)
> >                         pmu_name, alias->name);
> >       }
> >
> > +     list_for_each_entry_safe(a, tmp, &aliases, list) {
> > +             list_del(&a->list);
> > +             perf_pmu_free_alias(a);
>
> This looks ok.

Thanks!

>
> I also notice that we have other paths like this, where the allocated
> pmu (and aliases) are not freed for later error paths, it seems:
>
> parse_events_add_pmu() -> perf_pmu_find() -> pmu_lookup() ->
> pmu_add_cpu_aliases().
>
> I had a quick look at the rest of the series, and could not see if we
> fix up any of this.

Right, I also found that and wondered why ASAN didn't report it.
I think we should free all pmu instances from the pmus list.
But this can be a later work..

Thanks
Namhyung