From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pa0-f71.google.com (mail-pa0-f71.google.com [209.85.220.71]) by kanga.kvack.org (Postfix) with ESMTP id 87501828E1 for ; Tue, 5 Jul 2016 20:52:38 -0400 (EDT) Received: by mail-pa0-f71.google.com with SMTP id ts6so429982086pac.1 for ; Tue, 05 Jul 2016 17:52:38 -0700 (PDT) Received: from mail-pa0-x241.google.com (mail-pa0-x241.google.com. [2607:f8b0:400e:c03::241]) by mx.google.com with ESMTPS id e132si2849088pfg.292.2016.07.05.17.52.37 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 05 Jul 2016 17:52:37 -0700 (PDT) Received: by mail-pa0-x241.google.com with SMTP id ib6so3577675pad.3 for ; Tue, 05 Jul 2016 17:52:37 -0700 (PDT) From: js1304@gmail.com Subject: [PATCH v5] kasan/quarantine: fix bugs on qlist_move_cache() Date: Wed, 6 Jul 2016 09:52:28 +0900 Message-Id: <1467766348-22419-1-git-send-email-iamjoonsoo.kim@lge.com> Sender: owner-linux-mm@kvack.org List-ID: 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 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. v5: rename some variable for better readability v4: fix cache size bug s/cache->size/obj_cache->size/ v3: fix build warning Reviewed-by: Dmitry Vyukov Signed-off-by: Joonsoo Kim --- mm/kasan/quarantine.c | 29 +++++++++++------------------ 1 file changed, 11 insertions(+), 18 deletions(-) diff --git a/mm/kasan/quarantine.c b/mm/kasan/quarantine.c index 4973505..65793f1 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; + struct qlist_node *next = curr->next; + struct kmem_cache *obj_cache = qlink_to_cache(curr); + + if (obj_cache == cache) + qlist_put(to, curr, obj_cache->size); + else + qlist_put(from, curr, obj_cache->size); + + curr = next; } } -- 1.9.1 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org