From: Taylor Blau <me@ttaylorr.com>
To: Jeff King <peff@peff.net>
Cc: git@vger.kernel.org, Junio C Hamano <gitster@pobox.com>
Subject: Re: [PATCH v2 02/15] pack-bitmap: fix leak of haves/wants object lists
Date: Fri, 14 Feb 2020 16:15:52 -0800 [thread overview]
Message-ID: <20200215001552.GE11400@syl.local> (raw)
In-Reply-To: <20200214182211.GB150965@coredump.intra.peff.net>
On Fri, Feb 14, 2020 at 01:22:11PM -0500, Jeff King wrote:
> When we do a bitmap-aware revision traversal, we create an object_list
> for each of the "haves" and "wants" tips. After creating the result
> bitmaps these are no longer needed or used, but we never free the list
> memory.
>
> Signed-off-by: Jeff King <peff@peff.net>
> ---
> object.c | 9 +++++++++
> object.h | 2 ++
> pack-bitmap.c | 5 +++++
> 3 files changed, 16 insertions(+)
>
> diff --git a/object.c b/object.c
> index 142ef69399..4d11949b38 100644
> --- a/object.c
> +++ b/object.c
> @@ -307,6 +307,15 @@ int object_list_contains(struct object_list *list, struct object *obj)
> return 0;
> }
>
> +void object_list_free(struct object_list **list)
> +{
> + while (*list) {
> + struct object_list *p = *list;
> + *list = p->next;
> + free(p);
> + }
> +}
Hmm. I was going to write a comment saying more-or-less, "I think I'm
nitpicking here, but I'm not crazy about this as a 'while' loop". But,
when I wrote this as a 'for' loop instead, I wrote a use-after-free, and
then when I rid the code of that, it wasn't any more readable than the
version above.
> /*
> * A zero-length string to which object_array_entry::name can be
> * initialized without requiring a malloc/free.
> diff --git a/object.h b/object.h
> index 25f5ab3d54..2dbabfca0a 100644
> --- a/object.h
> +++ b/object.h
> @@ -151,6 +151,8 @@ struct object_list *object_list_insert(struct object *item,
>
> int object_list_contains(struct object_list *list, struct object *obj);
>
> +void object_list_free(struct object_list **list);
> +
> /* Object array handling .. */
> void add_object_array(struct object *obj, const char *name, struct object_array *array);
> void add_object_array_with_path(struct object *obj, const char *name, struct object_array *array, unsigned mode, const char *path);
> diff --git a/pack-bitmap.c b/pack-bitmap.c
> index 9ca356ee29..6c06099dc7 100644
> --- a/pack-bitmap.c
> +++ b/pack-bitmap.c
> @@ -787,10 +787,15 @@ struct bitmap_index *prepare_bitmap_walk(struct rev_info *revs)
> bitmap_git->result = wants_bitmap;
> bitmap_git->haves = haves_bitmap;
>
> + object_list_free(&wants);
> + object_list_free(&haves);
> +
Makes sense.
> return bitmap_git;
>
> cleanup:
> free_bitmap_index(bitmap_git);
> + object_list_free(&wants);
> + object_list_free(&haves);
Ditto.
> return NULL;
> }
>
> --
> 2.25.0.796.gcc29325708
Thanks,
Taylor
next prev parent reply other threads:[~2020-02-15 0:15 UTC|newest]
Thread overview: 73+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-13 2:15 [PATCH 0/13] combining object filters and bitmaps Jeff King
2020-02-13 2:16 ` [PATCH 01/13] pack-bitmap: factor out type iterator initialization Jeff King
2020-02-13 17:45 ` Junio C Hamano
2020-02-13 2:16 ` [PATCH 02/13] pack-bitmap: fix leak of haves/wants object lists Jeff King
2020-02-13 18:12 ` Junio C Hamano
2020-02-13 2:17 ` [PATCH 03/13] rev-list: fallback to non-bitmap traversal when filtering Jeff King
2020-02-13 18:19 ` Junio C Hamano
2020-02-13 18:40 ` Jeff King
2020-02-13 2:17 ` [PATCH 04/13] rev-list: consolidate bitmap-disabling options Jeff King
2020-02-13 2:18 ` [PATCH 05/13] rev-list: factor out bitmap-optimized routines Jeff King
2020-02-13 18:34 ` Junio C Hamano
2020-02-13 2:19 ` [PATCH 06/13] rev-list: make --count work with --objects Jeff King
2020-02-13 19:14 ` Junio C Hamano
2020-02-13 20:27 ` Jeff King
2020-02-13 2:20 ` [PATCH 07/13] rev-list: allow bitmaps when counting objects Jeff King
2020-02-13 21:47 ` Junio C Hamano
2020-02-13 22:27 ` Jeff King
2020-02-13 2:20 ` [PATCH 08/13] pack-bitmap: basic noop bitmap filter infrastructure Jeff King
2020-02-13 2:21 ` [PATCH 09/13] rev-list: use bitmap filters for traversal Jeff King
2020-02-13 22:22 ` Junio C Hamano
2020-02-13 22:34 ` Jeff King
2020-02-13 2:21 ` [PATCH 10/13] bitmap: add bitmap_unset() function Jeff King
2020-02-13 2:23 ` [PATCH 11/13] pack-bitmap: implement BLOB_NONE filtering Jeff King
2020-02-13 2:25 ` [PATCH 12/13] pack-bitmap: implement BLOB_LIMIT filtering Jeff King
2020-02-13 23:17 ` Junio C Hamano
2020-02-13 2:25 ` [PATCH 13/13] pack-objects: support filters with bitmaps Jeff King
2020-02-14 18:21 ` [PATCH v2 0/15] combining object filters and bitmaps Jeff King
2020-02-14 18:22 ` [PATCH v2 01/15] pack-bitmap: factor out type iterator initialization Jeff King
2020-02-15 0:10 ` Taylor Blau
2020-02-14 18:22 ` [PATCH v2 02/15] pack-bitmap: fix leak of haves/wants object lists Jeff King
2020-02-15 0:15 ` Taylor Blau [this message]
2020-02-15 6:46 ` Jeff King
2020-02-18 17:58 ` Derrick Stolee
2020-02-18 20:02 ` Jeff King
2020-02-14 18:22 ` [PATCH v2 03/15] rev-list: fallback to non-bitmap traversal when filtering Jeff King
2020-02-15 0:22 ` Taylor Blau
2020-02-14 18:22 ` [PATCH v2 04/15] pack-bitmap: refuse to do a bitmap traversal with pathspecs Jeff King
2020-02-14 19:03 ` Junio C Hamano
2020-02-14 20:51 ` Jeff King
2020-02-14 18:22 ` [PATCH v2 05/15] rev-list: factor out bitmap-optimized routines Jeff King
2020-02-15 0:35 ` Taylor Blau
2020-02-14 18:22 ` [PATCH v2 06/15] rev-list: make --count work with --objects Jeff King
2020-02-15 0:42 ` Taylor Blau
2020-02-15 6:48 ` Jeff King
2020-02-16 23:34 ` Junio C Hamano
2020-02-18 5:24 ` Jeff King
2020-02-18 17:28 ` Junio C Hamano
2020-02-18 19:55 ` Jeff King
2020-02-18 21:19 ` Junio C Hamano
2020-02-18 21:23 ` Jeff King
2020-02-18 18:05 ` Derrick Stolee
2020-02-18 19:59 ` Jeff King
2020-02-14 18:22 ` [PATCH v2 07/15] rev-list: allow bitmaps when counting objects Jeff King
2020-02-15 0:45 ` Taylor Blau
2020-02-15 6:55 ` Jeff King
2020-02-16 23:36 ` Junio C Hamano
2020-02-14 18:22 ` [PATCH v2 08/15] t5310: factor out bitmap traversal comparison Jeff King
2020-02-15 2:14 ` Taylor Blau
2020-02-15 7:00 ` Jeff King
2020-02-14 18:22 ` [PATCH v2 09/15] rev-list: allow commit-only bitmap traversals Jeff King
2020-02-18 18:18 ` Derrick Stolee
2020-02-18 20:05 ` Jeff King
2020-02-18 20:11 ` Derrick Stolee
2020-02-14 18:22 ` [PATCH v2 10/15] pack-bitmap: basic noop bitmap filter infrastructure Jeff King
2020-02-14 18:22 ` [PATCH v2 11/15] rev-list: use bitmap filters for traversal Jeff King
2020-02-14 18:22 ` [PATCH v2 12/15] bitmap: add bitmap_unset() function Jeff King
2020-02-14 18:22 ` [PATCH v2 13/15] pack-bitmap: implement BLOB_NONE filtering Jeff King
2020-02-18 19:26 ` Derrick Stolee
2020-02-18 19:36 ` Derrick Stolee
2020-02-18 20:30 ` Jeff King
2020-02-18 20:24 ` Jeff King
2020-02-14 18:22 ` [PATCH v2 14/15] pack-bitmap: implement BLOB_LIMIT filtering Jeff King
2020-02-14 18:22 ` [PATCH v2 15/15] pack-objects: support filters with bitmaps Jeff King
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