Re: [PATCH] ref-filter: fix memory leak in `free_array_item()`
- From
Junio C Hamano <gitster@pobox.com>
- Date
- Jul 10, 2019, 20:41 UTC
- Message-ID
- <xmqqr26xsjv7.fsf@gitster-ct.c.googlers.com>
- In-Reply-To
- <20190710183639.4123992-1-martin.agren@gmail.com>
Martin Ågren <martin.agren@gmail.com> writes:
> We treat the `value` pointer as a pointer to a struct and free its `s` > field. But `value` is in fact an array of structs. As a result, we only > free the first `s` out of `used_atom_cnt`-many and leak the rest. Make > sure we free all items in `value`.
Thanks for spotting. We do allocate an array of used_atom_cnt elements in populate_value() and we need to free them all.
> In the caller, `ref_array_clear()`, this means we need to be careful not > to zero `used_atom_cnt` until after we've called `free_array_item()`. We > could move just a single line, but let's keep related things close > together instead, by first handling `array`, then `used_atom`.
Yup. Looking good.
Thanks.
Show 42 quoted lines
>
> Signed-off-by: Martin Ågren <martin.agren@gmail.com>
> ---
> ref-filter.c | 14 +++++++++-----
> 1 file changed, 9 insertions(+), 5 deletions(-)
>
> diff --git a/ref-filter.c b/ref-filter.c
> index 791f0648a6..1c1a2af880 100644
> --- a/ref-filter.c
> +++ b/ref-filter.c
> @@ -2105,7 +2105,9 @@ static void free_array_item(struct ref_array_item *item)
> {
> free((char *)item->symref);
> if (item->value) {
> - free((char *)item->value->s);
> + int i;
> + for (i = 0; i < used_atom_cnt; i++)
> + free((char *)item->value[i].s);
> free(item->value);
> }
> free(item);
> @@ -2116,14 +2118,16 @@ void ref_array_clear(struct ref_array *array)
> {
> int i;
>
> - for (i = 0; i < used_atom_cnt; i++)
> - free((char *)used_atom[i].name);
> - FREE_AND_NULL(used_atom);
> - used_atom_cnt = 0;
> for (i = 0; i < array->nr; i++)
> free_array_item(array->items[i]);
> FREE_AND_NULL(array->items);
> array->nr = array->alloc = 0;
> +
> + for (i = 0; i < used_atom_cnt; i++)
> + free((char *)used_atom[i].name);
> + FREE_AND_NULL(used_atom);
> + used_atom_cnt = 0;
> +
> if (ref_to_worktree_map.worktrees) {
> hashmap_free(&(ref_to_worktree_map.map), 1);
> free_worktrees(ref_to_worktree_map.worktrees);