Re: [PATCH] perf hist: Fix memory leak of a perf_hpp_fmt

From: kajoljain <kjain@linux.ibm.com>
To: Ian Rogers <irogers@google.com>,
	Peter Zijlstra <peterz@infradead.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@redhat.com>, Namhyung Kim <namhyung@kernel.org>,
	linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org
Cc: Stephane Eranian <eranian@google.com>
Subject: Re: [PATCH] perf hist: Fix memory leak of a perf_hpp_fmt
Date: Thu, 18 Nov 2021 13:28:11 +0530	[thread overview]
Message-ID: <b4ad6246-b402-ebe7-d35a-2f485dccbaf4@linux.ibm.com> (raw)
In-Reply-To: <20211118071247.2140392-1-irogers@google.com>

On 11/18/21 12:42 PM, Ian Rogers wrote:
> perf_hpp__column_unregister removes an entry from a list but doesn't
> free the memory causing a memory leak spotted by leak sanitizer. Add the
> free while at the same time reducing the scope of the function to
> static.

Patch looks good to me.

Reviewed-by: Kajol Jain<kjain@linux.ibm.com>

Thanks,
Kajol jain

> 
> Signed-off-by: Ian Rogers <irogers@google.com>
> ---
>  tools/perf/ui/hist.c   | 28 ++++++++++++++--------------
>  tools/perf/util/hist.h |  1 -
>  2 files changed, 14 insertions(+), 15 deletions(-)
> 
> diff --git a/tools/perf/ui/hist.c b/tools/perf/ui/hist.c
> index c1f24d004852..5075ecead5f3 100644
> --- a/tools/perf/ui/hist.c
> +++ b/tools/perf/ui/hist.c
> @@ -535,6 +535,18 @@ struct perf_hpp_list perf_hpp_list = {
>  #undef __HPP_SORT_ACC_FN
>  #undef __HPP_SORT_RAW_FN
>  
> +static void fmt_free(struct perf_hpp_fmt *fmt)
> +{
> +	/*
> +	 * At this point fmt should be completely
> +	 * unhooked, if not it's a bug.
> +	 */
> +	BUG_ON(!list_empty(&fmt->list));
> +	BUG_ON(!list_empty(&fmt->sort_list));
> +
> +	if (fmt->free)
> +		fmt->free(fmt);
> +}
>  
>  void perf_hpp__init(void)
>  {
> @@ -598,9 +610,10 @@ void perf_hpp_list__prepend_sort_field(struct perf_hpp_list *list,
>  	list_add(&format->sort_list, &list->sorts);
>  }
>  
> -void perf_hpp__column_unregister(struct perf_hpp_fmt *format)
> +static void perf_hpp__column_unregister(struct perf_hpp_fmt *format)
>  {
>  	list_del_init(&format->list);
> +	fmt_free(format);
>  }
>  
>  void perf_hpp__cancel_cumulate(void)
> @@ -672,19 +685,6 @@ void perf_hpp__append_sort_keys(struct perf_hpp_list *list)
>  }
>  
>  
> -static void fmt_free(struct perf_hpp_fmt *fmt)
> -{
> -	/*
> -	 * At this point fmt should be completely
> -	 * unhooked, if not it's a bug.
> -	 */
> -	BUG_ON(!list_empty(&fmt->list));
> -	BUG_ON(!list_empty(&fmt->sort_list));
> -
> -	if (fmt->free)
> -		fmt->free(fmt);
> -}
> -
>  void perf_hpp__reset_output_field(struct perf_hpp_list *list)
>  {
>  	struct perf_hpp_fmt *fmt, *tmp;
> diff --git a/tools/perf/util/hist.h b/tools/perf/util/hist.h
> index 5343b62476e6..621f35ae1efa 100644
> --- a/tools/perf/util/hist.h
> +++ b/tools/perf/util/hist.h
> @@ -369,7 +369,6 @@ enum {
>  };
>  
>  void perf_hpp__init(void);
> -void perf_hpp__column_unregister(struct perf_hpp_fmt *format);
>  void perf_hpp__cancel_cumulate(void);
>  void perf_hpp__setup_output_field(struct perf_hpp_list *list);
>  void perf_hpp__reset_output_field(struct perf_hpp_list *list);
> 