* [PATCH] perf config: fix caching and memory leak in perf_home_perfconfig
@ 2021-08-20 13:08 Riccardo Mancini
2021-08-20 14:13 ` Arnaldo Carvalho de Melo
0 siblings, 1 reply; 4+ messages in thread
From: Riccardo Mancini @ 2021-08-20 13:08 UTC (permalink / raw)
To: Arnaldo Carvalho de Melo
Cc: Ian Rogers, Namhyung Kim, Riccardo Mancini, Jiri Olsa,
Peter Zijlstra, Ingo Molnar, Mark Rutland, Alexander Shishkin,
Jiri Olsa, Jin Yao, Song Liu, linux-perf-users, linux-kernel
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
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH] perf config: fix caching and memory leak in perf_home_perfconfig
2021-08-20 13:08 [PATCH] perf config: fix caching and memory leak in perf_home_perfconfig Riccardo Mancini
@ 2021-08-20 14:13 ` Arnaldo Carvalho de Melo
2021-08-20 19:58 ` Riccardo Mancini
0 siblings, 1 reply; 4+ messages in thread
From: Arnaldo Carvalho de Melo @ 2021-08-20 14:13 UTC (permalink / raw)
To: Riccardo Mancini
Cc: Ian Rogers, Namhyung Kim, Jiri Olsa, Peter Zijlstra, Ingo Molnar,
Mark Rutland, Alexander Shishkin, Jiri Olsa, Jin Yao, Song Liu,
linux-perf-users, linux-kernel
Em Fri, Aug 20, 2021 at 03:08:17PM +0200, Riccardo Mancini escreveu:
> 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();
humm, why keep the above failed test then?
> if (!config)
> failed = true;
I.e. please check this:
diff --git a/tools/perf/util/config.c b/tools/perf/util/config.c
index 63d472b336de21d4..4fb5e90d7a57ae48 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;
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH] perf config: fix caching and memory leak in perf_home_perfconfig
2021-08-20 14:13 ` Arnaldo Carvalho de Melo
@ 2021-08-20 19:58 ` Riccardo Mancini
2021-08-24 19:26 ` Arnaldo Carvalho de Melo
0 siblings, 1 reply; 4+ messages in thread
From: Riccardo Mancini @ 2021-08-20 19:58 UTC (permalink / raw)
To: Arnaldo Carvalho de Melo
Cc: Ian Rogers, Namhyung Kim, Jiri Olsa, Peter Zijlstra, Ingo Molnar,
Mark Rutland, Alexander Shishkin, Jiri Olsa, Jin Yao, Song Liu,
linux-perf-users, linux-kernel
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:
> > 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();
>
> humm, why keep the above failed test then?
Sorry, I forgot about that, it should be removed.
>
> > if (!config)
> > failed = true;
>
> I.e. please check this:
>
>
> diff --git a/tools/perf/util/config.c b/tools/perf/util/config.c
> index 63d472b336de21d4..4fb5e90d7a57ae48 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;
>
Looks good to me.
Shall I resend it fixed?
Thanks,
Riccardo
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] perf config: fix caching and memory leak in perf_home_perfconfig
2021-08-20 19:58 ` Riccardo Mancini
@ 2021-08-24 19:26 ` Arnaldo Carvalho de Melo
0 siblings, 0 replies; 4+ messages in thread
From: Arnaldo Carvalho de Melo @ 2021-08-24 19:26 UTC (permalink / raw)
To: Riccardo Mancini
Cc: Arnaldo Carvalho de Melo, Ian Rogers, Namhyung Kim, Jiri Olsa,
Peter Zijlstra, Ingo Molnar, Mark Rutland, Alexander Shishkin,
Jiri Olsa, Jin Yao, Song Liu, linux-perf-users, linux-kernel
Em Fri, Aug 20, 2021 at 09:58:16PM +0200, Riccardo Mancini escreveu:
> On Fri, 2021-08-20 at 11:13 -0300, Arnaldo Carvalho de Melo wrote:
> > diff --git a/tools/perf/util/config.c b/tools/perf/util/config.c
> > index 63d472b336de21d4..4fb5e90d7a57ae48 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;
> >
>
> Looks good to me.
> Shall I resend it fixed?
No need, I'll fix it and apply, thanks for checking!
- Arnaldo
^ permalink raw reply [flat|nested] 4+ messages in thread
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2021-08-20 13:08 [PATCH] perf config: fix caching and memory leak in perf_home_perfconfig Riccardo Mancini
2021-08-20 14:13 ` Arnaldo Carvalho de Melo
2021-08-20 19:58 ` Riccardo Mancini
2021-08-24 19:26 ` Arnaldo Carvalho de Melo
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