linux-kernel - [PATCH 5.14 140/168] perf config: Fix caching and memory leak in perf_home

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Message-Id: <20210920163926.257664516@linuxfoundation.org>
Date:   Mon, 20 Sep 2021 18:44:38 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Riccardo Mancini <rickyman7@...il.com>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Ian Rogers <irogers@...gle.com>,
        Jin Yao <yao.jin@...ux.intel.com>,
        Jiri Olsa <jolsa@...hat.com>,
        Mark Rutland <mark.rutland@....com>,
        Namhyung Kim <namhyung@...nel.org>,
        Peter Zijlstra <peterz@...radead.org>,
        Song Liu <song@...nel.org>,
        Arnaldo Carvalho de Melo <acme@...hat.com>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH 5.14 140/168] perf config: Fix caching and memory leak in perf_home_perfconfig()

From: Arnaldo Carvalho de Melo <acme@...nel.org>

[ Upstream commit 261f491133aecb943ccfdc3b3794e2d775607a87 ]

Acaict, perf_home_perfconfig() is supposed to cache the result of
home_perfconfig, which returns the default location of perfconfig for
the user, given the HOME environment variable.

However, the current implementation calls home_perfconfig every time
perf_home_perfconfig() is called (so no caching is actually performed),
replacing the previous pointer, thus also causing a memory leak.

This patch adds a check of whether either config or failed is set and,
in that case, directly returns config without calling home_perfconfig at
each invocation.

Fixes: f5f03e19ce14fc31 ("perf config: Add perf_home_perfconfig function")
Signed-off-by: Riccardo Mancini <rickyman7@...il.com>
Cc: Alexander Shishkin <alexander.shishkin@...ux.intel.com>
Cc: Ian Rogers <irogers@...gle.com>
Cc: Jin Yao <yao.jin@...ux.intel.com>
Cc: Jiri Olsa <jolsa@...hat.com>
Cc: Mark Rutland <mark.rutland@....com>
Cc: Namhyung Kim <namhyung@...nel.org>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Song Liu <song@...nel.org>
Link: http://lore.kernel.org/lkml/20210820130817.740536-1-rickyman7@gmail.com
[ Removed needless double check for the 'failed' variable ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@...hat.com>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 tools/perf/util/config.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/tools/perf/util/config.c b/tools/perf/util/config.c
index 63d472b336de..4fb5e90d7a57 100644
--- a/tools/perf/util/config.c
+++ b/tools/perf/util/config.c
@@ -581,7 +581,10 @@ const char *perf_home_perfconfig(void)
 	static const char *config;
 	static bool failed;
 
-	config = failed ? NULL : home_perfconfig();
+	if (failed || config)
+		return config;
+
+	config = home_perfconfig();
 	if (!config)
 		failed = true;
 
-- 
2.30.2