Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753002Ab0DFKJS (ORCPT ); Tue, 6 Apr 2010 06:09:18 -0400 Received: from fgwmail5.fujitsu.co.jp ([192.51.44.35]:50880 "EHLO fgwmail5.fujitsu.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752480Ab0DFKJN (ORCPT ); Tue, 6 Apr 2010 06:09:13 -0400 X-SecurityPolicyCheck-FJ: OK by FujitsuOutboundMailChecker v1.3.1 From: KOSAKI Motohiro To: KOSAKI Motohiro Subject: Re: Ugly rmap NULL ptr deref oopsie on hibernate (was Linux 2.6.34-rc3) Cc: kosaki.motohiro@jp.fujitsu.com, Linus Torvalds , Borislav Petkov , Rik van Riel , Andrew Morton , Linux Kernel Mailing List , Lee Schermerhorn , Minchan Kim , Nick Piggin , Andrea Arcangeli , Hugh Dickins In-Reply-To: <20100406173754.7E5A.A69D9226@jp.fujitsu.com> References: <20100406173754.7E5A.A69D9226@jp.fujitsu.com> Message-Id: <20100406190036.7E66.A69D9226@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit X-Mailer: Becky! ver. 2.50.07 [ja] Date: Tue, 6 Apr 2010 19:09:08 +0900 (JST) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 728 Lines: 17 > (b) is also impossible. SLAB_DESTROY_BY_RCU delay the page for anon_vma > freeing until next rcu period. It mean rcu_read_lock()+page_mapped() > can see kfree()ed page. but it is safe. noone corrupt it. by the way: I haven't understand why rik's per process anon_vma concept works correctly with ksm. ksm increase anon_vma->ksm_refcount. but it seems not guranteed vma->anon_vma and page->anon_vma are the same. but I guess bug reporter doesn't use ksm, it's minor feature. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/