From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx134.postini.com [74.125.245.134]) by kanga.kvack.org (Postfix) with SMTP id D9EDE6B004D for ; Mon, 14 May 2012 18:34:57 -0400 (EDT) Received: by wgbdt14 with SMTP id dt14so4609006wgb.26 for ; Mon, 14 May 2012 15:34:56 -0700 (PDT) Subject: Re: [PATCH v2] mm: Fix slab->page _count corruption. From: Eric Dumazet In-Reply-To: <1337034597-1826-1-git-send-email-pshelar@nicira.com> References: <1337034597-1826-1-git-send-email-pshelar@nicira.com> Content-Type: text/plain; charset="UTF-8" Date: Tue, 15 May 2012 00:34:52 +0200 Message-ID: <1337034892.8512.652.camel@edumazet-glaptop> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Pravin B Shelar Cc: cl@linux.com, penberg@kernel.org, mpm@selenic.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, jesse@nicira.com, abhide@nicira.com On Mon, 2012-05-14 at 15:29 -0700, Pravin B Shelar wrote: > On arches that do not support this_cpu_cmpxchg_double slab_lock is used > to do atomic cmpxchg() on double word which contains page->_count. > page count can be changed from get_page() or put_page() without taking > slab_lock. That corrupts page counter. > > Following patch fixes it by moving page->_count out of cmpxchg_double > data. So that slub does no change it while updating slub meta-data in > struct page. I say again : Page is owned by slub, so get_page() or put_page() is not allowed ? How is put_page() going to work with order-1 or order-2 allocations ? Me very confused by these Nicira patches. -- 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/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org