Index: main/utils.c
===================================================================
--- main/utils.c	(revision 426139)
+++ main/utils.c	(working copy)
@@ -2061,18 +2061,18 @@
 {
 	struct ast_string_field_pool *pool, *prev;
 
-	if (ptr == __ast_string_field_empty) {
-		return;
-	}
-
 	for (pool = pool_head, prev = NULL; pool; prev = pool, pool = pool->prev) {
 		if ((ptr >= pool->base) && (ptr <= (pool->base + pool->size))) {
 			pool->active -= AST_STRING_FIELD_ALLOCATION(ptr);
-			if ((pool->active == 0) && prev) {
+		}
+		if (pool->active == 0) {
+			if (prev) {
 				prev->prev = pool->prev;
 				ast_free(pool);
+				pool = prev;
+			} else {
+				pool->used = 0;
 			}
-			break;
 		}
 	}
 }