Re: [PATCH 05/11] perf parse-event: Fix memory leak in evsel->unit

From: Namhyung Kim <namhyung@kernel.org>
To: David Malcolm <dmalcolm@redhat.com>
Cc: Ian Rogers <irogers@google.com>,
	Arnaldo Carvalho de Melo <acme@kernel.org>,
	Jiri Olsa <jolsa@redhat.com>, 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 <ak@linux.intel.com>
Subject: Re: [PATCH 05/11] perf parse-event: Fix memory leak in evsel->unit
Date: Wed, 16 Sep 2020 16:12:24 +0900	[thread overview]
Message-ID: <CAM9d7cgtDq8yOFDEGEdTD9kN=Ko1gX=5o+tAB4+EDtN0WtGQPw@mail.gmail.com> (raw)
In-Reply-To: <0679eacce01f187037e726a45e6acdacde61f99d.camel@redhat.com>

Hello Ian and David,

Thank you for the good suggestions!

On Wed, Sep 16, 2020 at 4:56 AM David Malcolm <dmalcolm@redhat.com> wrote:
> Some ideas (with the caveat that I'm a GCC developer, and not a regular
> on LKML): can you capture the ownership status in the type system?
> I'm brainstorming here but how about:
>   typedef char *owned_string_t;
>   typedef const char *borrowed_string_t;
> This would at least capture the intent in human-readable form, and
> *might* make things more amenable to checking by a machine.  It's also
> less macro cruft.
> I take it that capturing the ownership status with a runtime flag next
> to the pointer in a struct is too expensive for your code?

Adding more random thoughts..

I think we can make it more generic like __attribute__((owned))
so that it can be applied to any pointers.  And we can use a
conventional macro like '__owned' in the declaration..

__owned char *name;
__owned char *strdup(const char *);
...

Thanks
Namhyung