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Sender: Ingo Molnar <mingo.kernel.org@gmail.com>
Date:   Fri, 24 Nov 2023 13:56:35 +0100
From:   Ingo Molnar <mingo@kernel.org>
To:     Peter Zijlstra <peterz@infradead.org>
Cc:     zhaimingbing <zhaimingbing@cmss.chinamobile.com>,
        Namhyung Kim <namhyung@kernel.org>,
        Ingo Molnar <mingo@redhat.com>,
        Arnaldo Carvalho de Melo <acme@kernel.org>,
        Mark Rutland <mark.rutland@arm.com>,
        Alexander Shishkin <alexander.shishkin@linux.intel.com>,
        Jiri Olsa <jolsa@kernel.org>, Ian Rogers <irogers@google.com>,
        Adrian Hunter <adrian.hunter@intel.com>,
        Sean Christopherson <seanjc@google.com>,
        Li Dong <lidong@vivo.com>, linux-perf-users@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH] perf lock: Fix a memory leak on an error path
Message-ID: <ZWCdg5gcizJitxVw@gmail.com>
References: <20231124092657.10392-1-zhaimingbing@cmss.chinamobile.com>
 <20231124095319.GN3818@noisy.programming.kicks-ass.net>
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* Peter Zijlstra <peterz@infradead.org> wrote:

> On Fri, Nov 24, 2023 at 05:26:57PM +0800, zhaimingbing wrote:
> > if a strdup-ed string is NULL,the allocated memory needs freeing.
> > 
> > Signed-off-by: zhaimingbing <zhaimingbing@cmss.chinamobile.com>
> > ---
> >  tools/perf/builtin-lock.c | 4 +++-
> >  1 file changed, 3 insertions(+), 1 deletion(-)
> > 
> > diff --git a/tools/perf/builtin-lock.c b/tools/perf/builtin-lock.c
> > index b141f2134..086041bcb 100644
> > --- a/tools/perf/builtin-lock.c
> > +++ b/tools/perf/builtin-lock.c
> > @@ -2228,8 +2228,10 @@ static int __cmd_record(int argc, const char **argv)
> >  		else
> >  			ev_name = strdup(contention_tracepoints[j].name);
> >  
> > -		if (!ev_name)
> > +		if (!ev_name) {
> > +			free(rec_argv);
> >  			return -ENOMEM;
> > +		}
> 
> Isn't this an error path straight into exit?

It increases the quality of implementation if resources are free()d 
consistently regardless of whether the task is going to exit() immediately, 
for example it makes it easier to validate perf for the lack of memory 
leaks with Valgrind.

Thanks,

	Ingo