linux-kernel - Re: [PATCH v1] perf record: fix memory leak on AIO objects deallocation

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Date:   Thu, 6 Dec 2018 21:10:09 +0300
From:   Alexey Budankov <alexey.budankov@...ux.intel.com>
To:     Arnaldo Carvalho de Melo <acme@...nel.org>
Cc:     Ingo Molnar <mingo@...hat.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Jiri Olsa <jolsa@...hat.com>,
        Namhyung Kim <namhyung@...nel.org>,
        Andi Kleen <ak@...ux.intel.com>,
        linux-kernel <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v1] perf record: fix memory leak on AIO objects
 deallocation

On 06.12.2018 20:05, Arnaldo Carvalho de Melo wrote:
> Em Wed, Dec 05, 2018 at 08:19:41PM +0300, Alexey Budankov escreveu:
>>
>> Sending a part which was missed between v12 and v13 of the patch set
>> introducing AIO trace streaming for perf record mode. 
>>
>> The part is essential to avoid memory leakage during deallocation
>> of AIO related trace data buffers.
>>
>> It is applied on top of acme perf/core repo.
>>
>> Signed-off-by: Alexey Budankov <alexey.budankov@...ux.intel.com>
>> ---
>> tools/perf/util/mmap.c | 10 ++++++++++
>>  1 file changed, 10 insertions(+)
>>
>> diff --git a/tools/perf/util/mmap.c b/tools/perf/util/mmap.c
>> index ab30555d2afc..169d02973757 100644
>> --- a/tools/perf/util/mmap.c
>> +++ b/tools/perf/util/mmap.c
>> @@ -207,8 +207,18 @@ static int perf_mmap__aio_mmap(struct perf_mmap *map, struct mmap_params *mp)
>>  
>>  static void perf_mmap__aio_munmap(struct perf_mmap *map)
>>  {
>> +	int i;
>> +
>> +	for (i = 0; i < map->aio.nr_cblocks; ++i) {
>> +		if (map->aio.data[i])
>> +			zfree(&map->aio.data[i]);
>> +	}
>>  	if (map->aio.data)
>>  		zfree(&map->aio.data);
>> +	if (map->aio.cblocks)
>> +		zfree(&map->aio.cblocks);
>> +	if (map->aio.aiocb)
>> +		zfree(&map->aio.aiocb);
> 
> There is no need to check for NULL before calling zfree(), as it is just
> a wrapper for free that sets that variable to NULL after calling it.
> 
> And free(NULL) is valid, just a noop to avoid having all those tests
> before each call to free(). I'm making those plain zfree() and later
> will do a sweep at removing other cases.

Thank you.
-Alexey

> 
>>  }
>>  
>>  int perf_mmap__aio_push(struct perf_mmap *md, void *to, int idx,
>