From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx184.postini.com [74.125.245.184]) by kanga.kvack.org (Postfix) with SMTP id 3F5C36B0044 for ; Tue, 25 Dec 2012 10:30:16 -0500 (EST) Received: by mail-oa0-f44.google.com with SMTP id n5so7522370oag.31 for ; Tue, 25 Dec 2012 07:30:15 -0800 (PST) MIME-Version: 1.0 In-Reply-To: <1356449082-3016-1-git-send-email-js1304@gmail.com> References: <1356449082-3016-1-git-send-email-js1304@gmail.com> Date: Wed, 26 Dec 2012 00:30:15 +0900 Message-ID: Subject: Re: [PATCH] slub: assign refcount for kmalloc_caches From: JoonSoo Kim Content-Type: text/plain; charset=ISO-8859-1 Sender: owner-linux-mm@kvack.org List-ID: To: Pekka Enberg Cc: Paul Hargrove , linux-kernel@vger.kernel.org, linux-mm@kvack.org, Joonsoo Kim , Christoph Lameter 2012/12/26 Joonsoo Kim : > commit cce89f4f6911286500cf7be0363f46c9b0a12ce0('Move kmem_cache > refcounting to common code') moves some refcount manipulation code to > common code. Unfortunately, it also removed refcount assignment for > kmalloc_caches. So, kmalloc_caches's refcount is initially 0. > This makes errornous situation. > > Paul Hargrove report that when he create a 8-byte kmem_cache and > destory it, he encounter below message. > 'Objects remaining in kmalloc-8 on kmem_cache_close()' > > 8-byte kmem_cache merge with 8-byte kmalloc cache and refcount is > increased by one. So, resulting refcount is 1. When destory it, it hit > refcount = 0, then kmem_cache_close() is executed and error message is > printed. > > This patch assign initial refcount 1 to kmalloc_caches, so fix this > errornous situtation. > > Cc: # v3.7 > Cc: Christoph Lameter > Reported-by: Paul Hargrove > Signed-off-by: Joonsoo Kim > > diff --git a/mm/slub.c b/mm/slub.c > index a0d6984..321afab 100644 > --- a/mm/slub.c > +++ b/mm/slub.c > @@ -3279,6 +3279,7 @@ static struct kmem_cache *__init create_kmalloc_cache(const char *name, > if (kmem_cache_open(s, flags)) > goto panic; > > + s->refcount = 1; > list_add(&s->list, &slab_caches); > return s; > > -- > 1.7.9.5 > I missed some explanation. In v3.8-rc1, this problem is already solved. See create_kmalloc_cache() in mm/slab_common.c. So this patch is just for v3.7 stable. -- 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