Re: [PATCH 15/22] negotiator/skipping: fix leaking commit entries

From: Calvin Wan <calvinwan@google.com>
Date: Aug 28, 2024, 20:29 UTC
Message-ID: <20240828202902.4156688-1-calvinwan@google.com>
In-Reply-To: <920db3a2912c609d4ac1fca2fc6b137513c8eceb.1724656120.git.ps@pks.im>

Patrick Steinhardt <ps@pks.im> writes:

Show 26 quoted lines

> When releasing the skipping negotiator we free its priority queue, but
> not the contained entries. Fix this to plug a memory leak.
> 
> Signed-off-by: Patrick Steinhardt <ps@pks.im>
> ---
>  negotiator/skipping.c                | 7 +++++--
>  t/t5552-skipping-fetch-negotiator.sh | 2 ++
>  2 files changed, 7 insertions(+), 2 deletions(-)
> 
> diff --git a/negotiator/skipping.c b/negotiator/skipping.c
> index f65d47858b4..b738fe4faef 100644
> --- a/negotiator/skipping.c
> +++ b/negotiator/skipping.c
> @@ -247,8 +247,11 @@ static int ack(struct fetch_negotiator *n, struct commit *c)
>  
>  static void release(struct fetch_negotiator *n)
>  {
> -	clear_prio_queue(&((struct data *)n->data)->rev_list);
> -	FREE_AND_NULL(n->data);
> +	struct data *data = n->data;
> +	for (int i = 0; i < data->rev_list.nr; i++)
> +		free(data->rev_list.array[i].data);
> +	clear_prio_queue(&data->rev_list);
> +	FREE_AND_NULL(data);
>  }
>

It seems unintuitive that clear_prio_queue() doesn't also free the data underneath and that a caller would have to know to free that as well to avoid leaking memory. Would it make more sense to add this change to clear_prio_queue() instead? Patch 14 has that pattern already.

Thanks again for the cleanups -- I'm tempted to take a stab at some of the other memory leaks you mentioned during our biweekly hackathon. All of the other patches look reasonable to me.