linux-kernel - Re: [PATCH 6/9] tools: convert map_groups.refcnt from atomic_t to refcount

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Message-ID: <20170222205533.GH20447@kernel.org>
Date:   Wed, 22 Feb 2017 17:55:33 -0300
From:   Arnaldo Carvalho de Melo <acme@...nel.org>
To:     Elena Reshetova <elena.reshetova@...el.com>
Cc:     linux-kernel@...r.kernel.org, alsa-devel@...a-project.org,
        peterz@...radead.org, gregkh@...uxfoundation.org, mingo@...hat.com,
        alexander.shishkin@...ux.intel.com, jolsa@...nel.org,
        mark.rutland@....com, akpm@...ux-foundation.org,
        matija.glavinic-pecotic.ext@...ia.com,
        Hans Liljestrand <ishkamiel@...il.com>,
        Kees Cook <keescook@...omium.org>,
        David Windsor <dwindsor@...il.com>
Subject: Re: [PATCH 6/9] tools: convert map_groups.refcnt from atomic_t to
 refcount_t

Em Tue, Feb 21, 2017 at 05:35:00PM +0200, Elena Reshetova escreveu:
> refcount_t type and corresponding API should be
> used instead of atomic_t when the variable is used as
> a reference counter. This allows to avoid accidental
> refcounter overflows that might lead to use-after-free
> situations.

You missed tools/perf/tests/thread-mg-share.c

I fixed it up.
 
> Signed-off-by: Elena Reshetova <elena.reshetova@...el.com>
> Signed-off-by: Hans Liljestrand <ishkamiel@...il.com>
> Signed-off-by: Kees Cook <keescook@...omium.org>
> Signed-off-by: David Windsor <dwindsor@...il.com>
> ---
>  tools/perf/util/map.c | 4 ++--
>  tools/perf/util/map.h | 4 ++--
>  2 files changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/tools/perf/util/map.c b/tools/perf/util/map.c
> index f0e2428..1d9ebcf 100644
> --- a/tools/perf/util/map.c
> +++ b/tools/perf/util/map.c
> @@ -485,7 +485,7 @@ void map_groups__init(struct map_groups *mg, struct machine *machine)
>  		maps__init(&mg->maps[i]);
>  	}
>  	mg->machine = machine;
> -	atomic_set(&mg->refcnt, 1);
> +	refcount_set(&mg->refcnt, 1);
>  }
>  
>  static void __maps__purge(struct maps *maps)
> @@ -547,7 +547,7 @@ void map_groups__delete(struct map_groups *mg)
>  
>  void map_groups__put(struct map_groups *mg)
>  {
> -	if (mg && atomic_dec_and_test(&mg->refcnt))
> +	if (mg && refcount_dec_and_test(&mg->refcnt))
>  		map_groups__delete(mg);
>  }
>  
> diff --git a/tools/perf/util/map.h b/tools/perf/util/map.h
> index 9545ff3..c8a5a64 100644
> --- a/tools/perf/util/map.h
> +++ b/tools/perf/util/map.h
> @@ -67,7 +67,7 @@ struct maps {
>  struct map_groups {
>  	struct maps	 maps[MAP__NR_TYPES];
>  	struct machine	 *machine;
> -	atomic_t	 refcnt;
> +	refcount_t	 refcnt;
>  };
>  
>  struct map_groups *map_groups__new(struct machine *machine);
> @@ -77,7 +77,7 @@ bool map_groups__empty(struct map_groups *mg);
>  static inline struct map_groups *map_groups__get(struct map_groups *mg)
>  {
>  	if (mg)
> -		atomic_inc(&mg->refcnt);
> +		refcount_inc(&mg->refcnt);
>  	return mg;
>  }
>  
> -- 
> 2.7.4