Re: [PATCH 1/9] perf evlist: Fix cpu/thread map leak

From: Jiri Olsa <jolsa@redhat.com>
To: Namhyung Kim <namhyung@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>,
	Ingo Molnar <mingo@kernel.org>,
	Peter Zijlstra <a.p.zijlstra@chello.nl>,
	Mark Rutland <mark.rutland@arm.com>,
	Alexander Shishkin <alexander.shishkin@linux.intel.com>,
	Stephane Eranian <eranian@google.com>,
	LKML <linux-kernel@vger.kernel.org>,
	Andi Kleen <andi@firstfloor.org>, Ian Rogers <irogers@google.com>
Subject: Re: [PATCH 1/9] perf evlist: Fix cpu/thread map leak
Date: Mon, 7 Sep 2020 13:32:01 +0200	[thread overview]
Message-ID: <20200907113201.GK1199773@krava> (raw)
In-Reply-To: <20200907112925.GJ1199773@krava>

On Mon, Sep 07, 2020 at 01:29:29PM +0200, Jiri Olsa wrote:
> On Mon, Sep 07, 2020 at 12:44:54PM +0900, Namhyung Kim wrote:
> > Asan reported leak of cpu and thread maps as they have one more
> > refcount than released.  I found that after setting evlist maps it
> > should release it's refcount.
> > 
> > It seems to be broken from the beginning so I chose the original
> > commit as the culprit.  But not sure how it's applied to stable trees
> > since there are many changes in the code after that.
> > 
> > Fixes: 7e2ed097538c5 ("perf evlist: Store pointer to the cpu and thread maps")
> > Fixes: 4112eb1899c0e ("perf evlist: Default to syswide target when no thread/cpu maps set")
> > Signed-off-by: Namhyung Kim <namhyung@kernel.org>
> > ---
> >  tools/perf/util/evlist.c | 11 ++++++++---
> >  1 file changed, 8 insertions(+), 3 deletions(-)
> > 
> > diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
> > index e3fa3bf7498a..c0768c61eb43 100644
> > --- a/tools/perf/util/evlist.c
> > +++ b/tools/perf/util/evlist.c
> > @@ -946,6 +946,10 @@ int perf_evlist__create_maps(struct evlist *evlist, struct target *target)
> >  
> >  	perf_evlist__set_maps(&evlist->core, cpus, threads);
> >  
> > +	/* as evlist now has references, put count here */
> > +	perf_cpu_map__put(cpus);
> > +	perf_thread_map__put(threads);
> 
> nice catch, I checked perf_evlist__create_syswide_maps is doing this

because you fixed that :))) missed the rest of the patch.. sry

jirka

> correctly, but I think we might have the same issue in script's
> set_maps function
> 
> thanks,
> jirka
> 
> > +
> >  	return 0;
> >  
> >  out_delete_threads:
> > @@ -1273,11 +1277,12 @@ static int perf_evlist__create_syswide_maps(struct evlist *evlist)
> >  		goto out_put;
> >  
> >  	perf_evlist__set_maps(&evlist->core, cpus, threads);
> > -out:
> > -	return err;
> > +
> > +	perf_thread_map__put(threads);
> >  out_put:
> >  	perf_cpu_map__put(cpus);
> > -	goto out;
> > +out:
> > +	return err;
> >  }
> >  
> >  int evlist__open(struct evlist *evlist)
> > -- 
> > 2.28.0.526.ge36021eeef-goog
> > 