diff mbox series

[v4,03/16] ref-filter: clear reachable list pointers after freeing

Message ID 7e6bf7766d020914af53e7d6926f5a6c4c4d0668.1687270849.git.me@ttaylorr.com (mailing list archive)
State Superseded
Headers show
Series refs: implement jump lists for packed backend | expand

Commit Message

Taylor Blau June 20, 2023, 2:21 p.m. UTC 
From: Jeff King <peff@peff.net>

In reach_filter(), we pop all commits from the reachable lists, leaving
them empty. But because we're operating on a list pointer that was
passed by value, the original filter.reachable_from pointer is left
dangling.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
---
 ref-filter.c | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

Comments

Jeff King July 3, 2023, 5:16 a.m. UTC | #1 
On Tue, Jun 20, 2023 at 10:21:11AM -0400, Taylor Blau wrote:

> From: Jeff King <peff@peff.net>
> 
> In reach_filter(), we pop all commits from the reachable lists, leaving
> them empty. But because we're operating on a list pointer that was
> passed by value, the original filter.reachable_from pointer is left
> dangling.

Yep. This isn't a bug (yet) because nobody looks at the now-dangling
pointer. So as with the last patch, we're future-proofing ourselves
against dangerous situations.

-Peff
diff mbox series

Patch

diff --git a/ref-filter.c b/ref-filter.c
index 4991cd4f7a..048d277cbf 100644
--- a/ref-filter.c
+++ b/ref-filter.c
@@ -2418,13 +2418,13 @@  void ref_array_clear(struct ref_array *array)
 #define EXCLUDE_REACHED 0
 #define INCLUDE_REACHED 1
 static void reach_filter(struct ref_array *array,
-			 struct commit_list *check_reachable,
+			 struct commit_list **check_reachable,
 			 int include_reached)
 {
 	int i, old_nr;
 	struct commit **to_clear;
 
-	if (!check_reachable)
+	if (!*check_reachable)
 		return;
 
 	CALLOC_ARRAY(to_clear, array->nr);
@@ -2434,7 +2434,7 @@  static void reach_filter(struct ref_array *array,
 	}
 
 	tips_reachable_from_bases(the_repository,
-				  check_reachable,
+				  *check_reachable,
 				  to_clear, array->nr,
 				  UNINTERESTING);
 
@@ -2455,8 +2455,8 @@  static void reach_filter(struct ref_array *array,
 
 	clear_commit_marks_many(old_nr, to_clear, ALL_REV_FLAGS);
 
-	while (check_reachable) {
-		struct commit *merge_commit = pop_commit(&check_reachable);
+	while (*check_reachable) {
+		struct commit *merge_commit = pop_commit(check_reachable);
 		clear_commit_marks(merge_commit, ALL_REV_FLAGS);
 	}
 
@@ -2553,8 +2553,8 @@  int filter_refs(struct ref_array *array, struct ref_filter *filter, unsigned int
 	clear_contains_cache(&ref_cbdata.no_contains_cache);
 
 	/*  Filters that need revision walking */
-	reach_filter(array, filter->reachable_from, INCLUDE_REACHED);
-	reach_filter(array, filter->unreachable_from, EXCLUDE_REACHED);
+	reach_filter(array, &filter->reachable_from, INCLUDE_REACHED);
+	reach_filter(array, &filter->unreachable_from, EXCLUDE_REACHED);
 
 	save_commit_buffer = save_commit_buffer_orig;
 	return ret;