Re: [PATCH] perf data: Fix double free in perf_session__delete

[Arnaldo Carvalho de Melo]

Em Fri, Feb 18, 2022 at 02:30:08PM +0300, Alexey Bayduraev escreveu:
> When perf_data__create_dir fails, it calls close_dir, but
> perf_session__delete also calls close_dir and since dir.version and
> dir.nr was initialized by perf_data__create_dir, a double free occurs.
> This patch moves the initialization of dir.version and dir.nr after
> successful initialization of dir.files, that prevents double freeing.
> This behavior is already implemented in perf_data__open_dir. The patch
> also adds a missing error message in case data directory creation fails.

Is this for perf/urgent or for perf/core? Probably perf/core as that
record__threads_enabled(rec) call hints.

Please state for which branch the patch should be applied, something
like;

[PATCH next] perf data: Fix double free in perf_session__delete()

Or:

[PATCH urgent] perf data: Fix double free in perf_session__delete()

- Arnaldo
 
> Signed-off-by: Alexey Bayduraev <alexey.v.bayduraev@xxxxxxxxxxxxxxx>
> ---
>  tools/perf/builtin-record.c | 4 +++-
>  tools/perf/util/data.c      | 7 +++----
>  2 files changed, 6 insertions(+), 5 deletions(-)
> 
> diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
> index 0bc6529814b2..0306d5911de2 100644
> --- a/tools/perf/builtin-record.c
> +++ b/tools/perf/builtin-record.c
> @@ -1186,8 +1186,10 @@ static int record__mmap_evlist(struct record *rec,
>  
>  	if (record__threads_enabled(rec)) {
>  		ret = perf_data__create_dir(&rec->data, evlist->core.nr_mmaps);
> -		if (ret)
> +		if (ret) {
> +			pr_err("Failed to create data directory: %s\n", strerror(errno));
>  			return ret;
> +		}
>  		for (i = 0; i < evlist->core.nr_mmaps; i++) {
>  			if (evlist->mmap)
>  				evlist->mmap[i].file = &rec->data.dir.files[i];
> diff --git a/tools/perf/util/data.c b/tools/perf/util/data.c
> index f5d260b1df4d..15a4547d608e 100644
> --- a/tools/perf/util/data.c
> +++ b/tools/perf/util/data.c
> @@ -44,10 +44,6 @@ int perf_data__create_dir(struct perf_data *data, int nr)
>  	if (!files)
>  		return -ENOMEM;
>  
> -	data->dir.version = PERF_DIR_VERSION;
> -	data->dir.files   = files;
> -	data->dir.nr      = nr;
> -
>  	for (i = 0; i < nr; i++) {
>  		struct perf_data_file *file = &files[i];
>  
> @@ -62,6 +58,9 @@ int perf_data__create_dir(struct perf_data *data, int nr)
>  		file->fd = ret;
>  	}
>  
> +	data->dir.version = PERF_DIR_VERSION;
> +	data->dir.files   = files;
> +	data->dir.nr      = nr;
>  	return 0;
>  
>  out_err:
> -- 
> 2.19.0

-- 

- Arnaldo