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    SubjectRe: [PATCH 01/20] perf nsinfo: fix refcounting
    Em Thu, Jul 15, 2021 at 04:02:16PM -0300, Arnaldo Carvalho de Melo escreveu:
    > Em Thu, Jul 15, 2021 at 06:07:06PM +0200, Riccardo Mancini escreveu:
    > > ASan reports a memory leak of nsinfo during the execution of the perf
    > > test "31: Lookup mmap thread".
    > > The leak is caused by a refcounted variable being replaced without
    > > dropping the refcount.

    > > This patch makes sure that the refcnt of nsinfo is decreased whenever
    > > a refcounted variable is replaced with a new value.

    > So, there are multiple fixes in just one patch, I'll split it into
    > three, no need to resend.

    > I'll try and check if finding Fixes: for the three is easy, that way
    > stable@vger.kernel.org will figure out which of the supported releases
    > need each of them.

    The second is at the end of this message, and looking at it I think
    there is a problem with where this nsinfo reference is stored, it should
    be in the 'struct map', that is per-thread, not in the 'struct dso',
    that may be shared by multiple 'struct map's in different cgroups, so we
    can't set dso->nsinfo in map__new(), right? Kristen?

    - Arnaldo

    commit 280f3933661f9ca9563ed04ce82313fdbcbb8f75
    Author: Riccardo Mancini <rickyman7@gmail.com>
    Date: Thu Jul 15 18:07:06 2021 +0200

    perf map: Fix dso->nsinfo refcounting

    ASan reports a memory leak of nsinfo during the execution of

    # perf test "31: Lookup mmap thread"

    The leak is caused by a refcounted variable being replaced without
    dropping the refcount.

    This patch makes sure that the refcnt of nsinfo is decreased whenever a
    refcounted variable is replaced with a new value.

    Signed-off-by: Riccardo Mancini <rickyman7@gmail.com>
    Fixes: bf2e710b3cb8445c ("perf maps: Lookup maps in both intitial mountns and inner mountns.")
    Cc: Ian Rogers <irogers@google.com>
    Cc: Jiri Olsa <jolsa@redhat.com>
    Cc: Krister Johansen <kjlx@templeofstupid.com>
    Cc: Mark Rutland <mark.rutland@arm.com>
    Cc: Namhyung Kim <namhyung@kernel.org>
    Cc: Peter Zijlstra <peterz@infradead.org>
    Link: http://lore.kernel.org/lkml/55223bc8821b34ccb01f92ef1401c02b6a32e61f.1626343282.git.rickyman7@gmail.com
    Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

    diff --git a/tools/perf/util/map.c b/tools/perf/util/map.c
    index 8af693d9678cefe0..72e7f3616157ead4 100644
    --- a/tools/perf/util/map.c
    +++ b/tools/perf/util/map.c
    @@ -192,6 +192,8 @@ struct map *map__new(struct machine *machine, u64 start, u64 len,
    if (!(prot & PROT_EXEC))
    dso__set_loaded(dso);
    }
    +
    + nsinfo__put(dso->nsinfo);
    dso->nsinfo = nsi;

    if (build_id__is_defined(bid))
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