Re: [PATCH] perf config: fix caching and memory leak in perf_home_perfconfig

Hi,

On Fri, 2021-08-20 at 11:13 -0300, Arnaldo Carvalho de Melo wrote:

Em Fri, Aug 20, 2021 at 03:08:17PM +0200, Riccardo Mancini escreveu:

quoted

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 <redacted>
---
 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();

humm, why keep the above failed test then?

Sorry, I forgot about that, it should be removed.

Looks good to me.
Shall I resend it fixed?

Thanks,
Riccardo