From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751276AbcGDEbi (ORCPT ); Mon, 4 Jul 2016 00:31:38 -0400 Received: from mail-pf0-f196.google.com ([209.85.192.196]:33309 "EHLO mail-pf0-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750737AbcGDEbh (ORCPT ); Mon, 4 Jul 2016 00:31:37 -0400 From: js1304@gmail.com X-Google-Original-From: iamjoonsoo.kim@lge.com To: Andrew Morton Cc: Andrey Ryabinin , Alexander Potapenko , Dmitry Vyukov , kasan-dev@googlegroups.com, Kuthonuzo Luruo , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Joonsoo Kim Subject: [PATCH v4] kasan/quarantine: fix bugs on qlist_move_cache() Date: Mon, 4 Jul 2016 13:31:54 +0900 Message-Id: <1467606714-30231-1-git-send-email-iamjoonsoo.kim@lge.com> X-Mailer: git-send-email 1.9.1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Joonsoo Kim There are two bugs on qlist_move_cache(). One is that qlist's tail isn't set properly. curr->next can be NULL since it is singly linked list and NULL value on tail is invalid if there is one item on qlist. Another one is that if cache is matched, qlist_put() is called and it will set curr->next to NULL. It would cause to stop the loop prematurely. These problems come from complicated implementation so I'd like to re-implement it completely. Implementation in this patch is really simple. Iterate all qlist_nodes and put them to appropriate list. Unfortunately, I got this bug sometime ago and lose oops message. But, the bug looks trivial and no need to attach oops. v4: fix cache size bug s/cache->size/obj_cache->size/ v3: fix build warning Signed-off-by: Joonsoo Kim --- mm/kasan/quarantine.c | 21 +++++++-------------- 1 file changed, 7 insertions(+), 14 deletions(-) diff --git a/mm/kasan/quarantine.c b/mm/kasan/quarantine.c index 4973505..b2e1827 100644 --- a/mm/kasan/quarantine.c +++ b/mm/kasan/quarantine.c @@ -238,30 +238,23 @@ static void qlist_move_cache(struct qlist_head *from, struct qlist_head *to, struct kmem_cache *cache) { - struct qlist_node *prev = NULL, *curr; + struct qlist_node *curr; if (unlikely(qlist_empty(from))) return; curr = from->head; + qlist_init(from); while (curr) { struct qlist_node *qlink = curr; struct kmem_cache *obj_cache = qlink_to_cache(qlink); - if (obj_cache == cache) { - if (unlikely(from->head == qlink)) { - from->head = curr->next; - prev = curr; - } else - prev->next = curr->next; - if (unlikely(from->tail == qlink)) - from->tail = curr->next; - from->bytes -= cache->size; - qlist_put(to, qlink, cache->size); - } else { - prev = curr; - } curr = curr->next; + + if (obj_cache == cache) + qlist_put(to, qlink, obj_cache->size); + else + qlist_put(from, qlink, obj_cache->size); } } -- 1.9.1