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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Riccardo Mancini <rickyman7@gmail.com>,
        Ian Rogers <irogers@google.com>, Jiri Olsa <jolsa@redhat.com>,
        Krister Johansen <kjlx@templeofstupid.com>,
        Mark Rutland <mark.rutland@arm.com>,
        Namhyung Kim <namhyung@kernel.org>,
        Peter Zijlstra <peterz@infradead.org>,
        Arnaldo Carvalho de Melo <acme@redhat.com>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.4 020/108] perf map: Fix dso->nsinfo refcounting
Date:   Mon, 26 Jul 2021 17:38:21 +0200
Message-Id: <20210726153832.341314423@linuxfoundation.org>
In-Reply-To: <20210726153831.696295003@linuxfoundation.org>
References: <20210726153831.696295003@linuxfoundation.org>
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From: Riccardo Mancini <rickyman7@gmail.com>

[ Upstream commit 2d6b74baa7147251c30a46c4996e8cc224aa2dc5 ]

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
[ Split from a larger patch ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 tools/perf/util/map.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/tools/perf/util/map.c b/tools/perf/util/map.c
index 571e99c908a0..1ae5c51a7035 100644
--- a/tools/perf/util/map.c
+++ b/tools/perf/util/map.c
@@ -214,6 +214,8 @@ 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;
 		dso__put(dso);
 	}
-- 
2.30.2