From: Stefan Metzmacher <metze@samba.org>
Date: Thu, 23 Jul 2009 11:43:46 +0000 (+0200)
Subject: more fixes
X-Git-Url: http://git.samba.org/?p=metze%2Fsamba%2Fwip.git;a=commitdiff_plain;h=refs%2Fheads%2Fmaster4-talloc-sam

more fixes
---

diff --git a/lib/talloc/talloc.c b/lib/talloc/talloc.c
index 6913c0885160..e28d91fc68c5 100644
--- a/lib/talloc/talloc.c
+++ b/lib/talloc/talloc.c
@@ -280,7 +280,8 @@ const char *talloc_parent_name(const void *ptr)
 	return tc? tc->name : NULL;
 }
 
-static inline void talloc_remove_from_parent(struct talloc_chunk *tc)
+static inline void talloc_remove_from_parent(struct talloc_chunk *tc,
+					     bool reset_parent)
 {
 	if (!TALLOC_INVALID_PARENT(tc)) {
 		_TLIST_REMOVE(tc->parent->child, tc);
@@ -291,7 +292,13 @@ static inline void talloc_remove_from_parent(struct talloc_chunk *tc)
 		if (tc->prev) tc->prev->next = tc->next;
 		if (tc->next) tc->next->prev = tc->prev;
 	}
-//	tc->parent = tc->prec = tc->next = NULL;
+	tc->prev = tc->next = NULL;
+	/*
+	 * Note: we only reset tc->parent = NULL when the caller asked for it
+	 */
+	if (reset_parent) {
+		tc->parent = NULL;
+	}
 }
 
 /*
@@ -603,10 +610,6 @@ static inline int _talloc_free(void *ptr)
 	tc = talloc_chunk_from_ptr(ptr);
 
 	if (unlikely(tc->refs)) {
-	/*TODO: Fix this loop detection. The code here breaks top reference if
-	        it is also one of our children. It is insufficient and can lead
-	        to dangling references */
-
 		int is_child;
 		/* check this is a reference from a child or grantchild
 		 * back to it's parent or grantparent
@@ -656,7 +659,13 @@ static inline int _talloc_free(void *ptr)
 		tc->destructor = NULL;
 	}
 
-	talloc_remove_from_parent(tc);
+	/*
+	 * Note: we ask talloc_remove_from_parent() to keep
+	 *       tc->parent valid, because _talloc_free_children()
+	 *       needs it to find the parent for child where
+	 *       the destructor rejects the _talloc_free()
+	 */
+	talloc_remove_from_parent(tc, false);
 
 	_talloc_free_children(tc);
 
@@ -721,9 +730,8 @@ void *_talloc_steal(const void *new_ctx, const void *ptr)
 	tc = talloc_chunk_from_ptr(ptr);
 
 	if (unlikely(new_ctx == NULL)) {
-		talloc_remove_from_parent(tc);
+		talloc_remove_from_parent(tc, true);
 
-		tc->parent = tc->next = tc->prev = NULL;
 		if (unlikely(no_owner_null)) {
 			tc->parent = TALLOC_MAGIC_NO_OWNER_TC;
 		}
@@ -736,7 +744,7 @@ void *_talloc_steal(const void *new_ctx, const void *ptr)
 		return discard_const_p(void, ptr);
 	}
 
-	talloc_remove_from_parent(tc);
+	talloc_remove_from_parent(tc, true);
 
 	tc->parent = new_tc;
 	if (new_tc->child) new_tc->child->parent = NULL;