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From:   Riccardo Mancini <rickyman7@gmail.com>
To:     Arnaldo Carvalho de Melo <acme@kernel.org>
Cc:     Ian Rogers <irogers@google.com>,
        Namhyung Kim <namhyung@kernel.org>,
        Riccardo Mancini <rickyman7@gmail.com>,
        Jiri Olsa <jolsa@kernel.org>,
        Peter Zijlstra <peterz@infradead.org>,
        Ingo Molnar <mingo@redhat.com>,
        Mark Rutland <mark.rutland@arm.com>,
        Alexander Shishkin <alexander.shishkin@linux.intel.com>,
        Jiri Olsa <jolsa@redhat.com>,
        Jin Yao <yao.jin@linux.intel.com>, Song Liu <song@kernel.org>,
        linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH] perf config: fix caching and memory leak in perf_home_perfconfig
Date:   Fri, 20 Aug 2021 15:08:17 +0200
Message-Id: <20210820130817.740536-1-rickyman7@gmail.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

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.

Cc: Jiri Olsa <jolsa@kernel.org>
Fixes: f5f03e19ce14fc31 ("perf config: Add perf_home_perfconfig function")
Signed-off-by: Riccardo Mancini <rickyman7@gmail.com>
---
 tools/perf/util/config.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/tools/perf/util/config.c b/tools/perf/util/config.c
index 63d472b336de21d4..6ab670cdf512507e 100644
--- a/tools/perf/util/config.c
+++ b/tools/perf/util/config.c
@@ -581,6 +581,9 @@ const char *perf_home_perfconfig(void)
 	static const char *config;
 	static bool failed;
 
+	if (config || failed)
+		return config;
+
 	config = failed ? NULL : home_perfconfig();
 	if (!config)
 		failed = true;
-- 
2.31.1