Re: [PATCH v2 26/26] perf hist: Fix srcline memory leak

From: Arnaldo Carvalho de Melo <acme@kernel.org>
To: Ian Rogers <irogers@google.com>
Cc: John Garry <john.g.garry@oracle.com>,
	Will Deacon <will@kernel.org>, James Clark <james.clark@arm.com>,
	Mike Leach <mike.leach@linaro.org>, Leo Yan <leo.yan@linaro.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@kernel.org>, Namhyung Kim <namhyung@kernel.org>,
	Adrian Hunter <adrian.hunter@intel.com>,
	Suzuki K Poulose <suzuki.poulose@arm.com>,
	"Naveen N. Rao" <naveen.n.rao@linux.vnet.ibm.com>,
	Kan Liang <kan.liang@linux.intel.com>,
	German Gomez <german.gomez@arm.com>,
	Ali Saidi <alisaidi@amazon.com>,
	Jing Zhang <renyu.zj@linux.alibaba.com>,
	Athira Rajeev <atrajeev@linux.vnet.ibm.com>,
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	Liam Howlett <liam.howlett@oracle.com>,
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	Yang Jihong <yangjihong1@huawei.com>,
	K Prateek Nayak <kprateek.nayak@amd.com>,
	Changbin Du <changbin.du@huawei.com>,
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	Sean Christopherson <seanjc@google.com>,
	Andi Kleen <ak@linux.intel.com>,
	"Steinar H. Gunderson" <sesse@google.com>,
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	Brian Robbins <brianrob@linux.microsoft.com>,
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	Fangrui Song <maskray@google.com>,
	linux-kernel@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org,
	linux-perf-users@vger.kernel.org, coresight@lists.linaro.org
Subject: Re: [PATCH v2 26/26] perf hist: Fix srcline memory leak
Date: Mon, 12 Jun 2023 14:23:41 -0300	[thread overview]
Message-ID: <ZIdUncwTt2fBzxKh@kernel.org> (raw)
In-Reply-To: <CAP-5=fXby-Yk3U4LCQeYkGU_E22kd92=dCnfb7DkN5iPYvCDGA@mail.gmail.com>

Em Mon, Jun 12, 2023 at 07:46:14AM -0700, Ian Rogers escreveu:
> On Mon, Jun 12, 2023 at 7:16 AM Arnaldo Carvalho de Melo
> <acme@kernel.org> wrote:
> >
> > Em Mon, Jun 12, 2023 at 11:13:59AM -0300, Arnaldo Carvalho de Melo escreveu:
> > > Em Thu, Jun 08, 2023 at 04:28:23PM -0700, Ian Rogers escreveu:
> > > > srcline isn't freed if it is SRCLINE_UNKNOWN. Avoid strduping in this
> > > > case as such strdups are redundant and leak memory.
> > >
> > > The patch is ok as its what the rest of the code is doing, i.e. strcmp()
> > > to check if a srcline is the unknown one, but how about the following
> > > patch on top of yours?
> >
> > [acme@quaco perf-tools-next]$ strings ~/bin/perf | grep '??:0'
> > ??:0
> > SRCLINE_UNKNOWN ((char *) "??:0")
> > [acme@quaco perf-tools-next]$
> 
> Agreed, the strcmps make me nervous as they won't distinguish heap
> from a global meaning we could end up with things like pointers to
> freed memory. The comparison with the global is always going to be
> same imo.
> 
> Acked-by: Ian Rogers <irogers@google.com>

Thanks, applied and added your Acked-by.

- Arnaldo