[PATCH 5.10 034/167] perf map: Fix dso->nsinfo refcounting

From: Greg Kroah-Hartman
Date: Mon Jul 26 2021 - 12:19:32 EST

From: Riccardo Mancini <rickyman7@xxxxxxxxx>

[ 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@xxxxxxxxx>
Fixes: bf2e710b3cb8445c ("perf maps: Lookup maps in both intitial mountns and inner mountns.")
Cc: Ian Rogers <irogers@xxxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Krister Johansen <kjlx@xxxxxxxxxxxxxxxxxx>
Cc: Mark Rutland <mark.rutland@xxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Link: http://lore.kernel.org/lkml/55223bc8821b34ccb01f92ef1401c02b6a32e61f.1626343282.git.rickyman7@xxxxxxxxx
[ Split from a larger patch ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
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 f4d44f75ba15..6688f6b253a7 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))
+ nsinfo__put(dso->nsinfo);
dso->nsinfo = nsi;