Merge branch 'ne/alloc-free-and-null'

gitster · gitster · commit 44c0d062bd2f · 2025-09-18T10:07:02.000-07:00
The clear_alloc_state() API function was not fully clearing the
structure for reuse, but since nobody reuses it, replace it with a
variant that frees the structure as well, making the callers simpler.

* ne/alloc-free-and-null:
  alloc: fix dangling pointer in alloc_state cleanup
diff --git a/alloc.c b/alloc.c
@@ -36,19 +36,25 @@ struct alloc_state {
 	int slab_nr, slab_alloc;
 };
 
-struct alloc_state *allocate_alloc_state(void)
+struct alloc_state *alloc_state_alloc(void)
 {
 	return xcalloc(1, sizeof(struct alloc_state));
 }
 
-void clear_alloc_state(struct alloc_state *s)
+void alloc_state_free_and_null(struct alloc_state **s_)
 {
+	struct alloc_state *s = *s_;
+
+	if (!s)
+		return;
+
 	while (s->slab_nr > 0) {
 		s->slab_nr--;
 		free(s->slabs[s->slab_nr]);
 	}
 
 	FREE_AND_NULL(s->slabs);
+	FREE_AND_NULL(*s_);
 }
 
 static inline void *alloc_node(struct alloc_state *s, size_t node_size)
diff --git a/alloc.h b/alloc.h
@@ -14,7 +14,7 @@ void *alloc_commit_node(struct repository *r);
 void *alloc_tag_node(struct repository *r);
 void *alloc_object_node(struct repository *r);
 
-struct alloc_state *allocate_alloc_state(void);
-void clear_alloc_state(struct alloc_state *s);
+struct alloc_state *alloc_state_alloc(void);
+void alloc_state_free_and_null(struct alloc_state **s_);
 
 #endif
diff --git a/object.c b/object.c
@@ -517,12 +517,11 @@ struct parsed_object_pool *parsed_object_pool_new(struct repository *repo)
 	memset(o, 0, sizeof(*o));
 
 	o->repo = repo;
-	o->blob_state = allocate_alloc_state();
-	o->tree_state = allocate_alloc_state();
-	o->commit_state = allocate_alloc_state();
-	o->tag_state = allocate_alloc_state();
-	o->object_state = allocate_alloc_state();
-
+	o->blob_state = alloc_state_alloc();
+	o->tree_state = alloc_state_alloc();
+	o->commit_state = alloc_state_alloc();
+	o->tag_state = alloc_state_alloc();
+	o->object_state = alloc_state_alloc();
 	o->is_shallow = -1;
 	CALLOC_ARRAY(o->shallow_stat, 1);
 
@@ -573,16 +572,11 @@ void parsed_object_pool_clear(struct parsed_object_pool *o)
 	o->buffer_slab = NULL;
 
 	parsed_object_pool_reset_commit_grafts(o);
-	clear_alloc_state(o->blob_state);
-	clear_alloc_state(o->tree_state);
-	clear_alloc_state(o->commit_state);
-	clear_alloc_state(o->tag_state);
-	clear_alloc_state(o->object_state);
+	alloc_state_free_and_null(&o->blob_state);
+	alloc_state_free_and_null(&o->tree_state);
+	alloc_state_free_and_null(&o->commit_state);
+	alloc_state_free_and_null(&o->tag_state);
+	alloc_state_free_and_null(&o->object_state);
 	stat_validity_clear(o->shallow_stat);
-	FREE_AND_NULL(o->blob_state);
-	FREE_AND_NULL(o->tree_state);
-	FREE_AND_NULL(o->commit_state);
-	FREE_AND_NULL(o->tag_state);
-	FREE_AND_NULL(o->object_state);
 	FREE_AND_NULL(o->shallow_stat);
 }

Original file line number	Diff line number	Diff line change
`@@ -36,19 +36,25 @@ struct alloc_state {`
`36`	`36`	`int slab_nr, slab_alloc;`
`37`	`37`	`};`
`38`	`38`
`39`		`-struct alloc_state *allocate_alloc_state(void)`
	`39`	`+struct alloc_state *alloc_state_alloc(void)`
`40`	`40`	`{`
`41`	`41`	`return xcalloc(1, sizeof(struct alloc_state));`
`42`	`42`	`}`
`43`	`43`
`44`		`-void clear_alloc_state(struct alloc_state *s)`
	`44`	`+void alloc_state_free_and_null(struct alloc_state **s_)`
`45`	`45`	`{`
	`46`	`+ struct alloc_state s = s_;`
	`47`	`+`
	`48`	`+ if (!s)`
	`49`	`+ return;`
	`50`	`+`
`46`	`51`	`while (s->slab_nr > 0) {`
`47`	`52`	`s->slab_nr--;`
`48`	`53`	`free(s->slabs[s->slab_nr]);`
`49`	`54`	`}`
`50`	`55`
`51`	`56`	`FREE_AND_NULL(s->slabs);`
	`57`	`+ FREE_AND_NULL(*s_);`
`52`	`58`	`}`
`53`	`59`
`54`	`60`	`static inline void alloc_node(struct alloc_state s, size_t node_size)`