From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932092AbcGAOCC (ORCPT ); Fri, 1 Jul 2016 10:02:02 -0400 Received: from mail-pf0-f194.google.com ([209.85.192.194]:36346 "EHLO mail-pf0-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752028AbcGAOCA (ORCPT ); Fri, 1 Jul 2016 10:02:00 -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, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Joonsoo Kim Subject: [PATCH v3] kasan/quarantine: fix bugs on qlist_move_cache() Date: Fri, 1 Jul 2016 23:02:13 +0900 Message-Id: <1467381733-18314-1-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. 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..cf92494 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, cache->size); + else + qlist_put(from, qlink, cache->size); } } -- 1.9.1