From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.5 required=3.0 tests=MAILING_LIST_MULTI,SPF_PASS, URIBL_BLOCKED,USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9761AC6778A for ; Mon, 2 Jul 2018 12:15:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4C1642526C for ; Mon, 2 Jul 2018 12:15:35 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4C1642526C Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752567AbeGBMPe (ORCPT ); Mon, 2 Jul 2018 08:15:34 -0400 Received: from mx2.suse.de ([195.135.220.15]:56710 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751761AbeGBMPb (ORCPT ); Mon, 2 Jul 2018 08:15:31 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay1.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 8D935AD06; Mon, 2 Jul 2018 12:15:29 +0000 (UTC) Date: Mon, 2 Jul 2018 14:15:28 +0200 From: Michal Hocko To: Laurent Dufour Cc: Yang Shi , willy@infradead.org, akpm@linux-foundation.org, peterz@infradead.org, mingo@redhat.com, acme@kernel.org, alexander.shishkin@linux.intel.com, jolsa@redhat.com, namhyung@kernel.org, tglx@linutronix.de, hpa@zytor.com, linux-mm@kvack.org, x86@kernel.org, linux-kernel@vger.kernel.org Subject: Re: [RFC v3 PATCH 5/5] x86: check VM_DEAD flag in page fault Message-ID: <20180702121528.GM19043@dhcp22.suse.cz> References: <1530311985-31251-1-git-send-email-yang.shi@linux.alibaba.com> <1530311985-31251-6-git-send-email-yang.shi@linux.alibaba.com> <84eba553-2e0b-1a90-d543-6b22c1b3c5f8@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <84eba553-2e0b-1a90-d543-6b22c1b3c5f8@linux.vnet.ibm.com> User-Agent: Mutt/1.10.0 (2018-05-17) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon 02-07-18 10:45:03, Laurent Dufour wrote: > On 30/06/2018 00:39, Yang Shi wrote: > > Check VM_DEAD flag of vma in page fault handler, if it is set, trigger > > SIGSEGV. > > > > Cc: Michal Hocko > > Cc: Thomas Gleixner > > Cc: Ingo Molnar > > Cc: "H. Peter Anvin" > > Signed-off-by: Yang Shi > > --- > > arch/x86/mm/fault.c | 4 ++++ > > 1 file changed, 4 insertions(+) > > > > diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c > > index 9a84a0d..3fd2da5 100644 > > --- a/arch/x86/mm/fault.c > > +++ b/arch/x86/mm/fault.c > > @@ -1357,6 +1357,10 @@ static inline bool smap_violation(int error_code, struct pt_regs *regs) > > bad_area(regs, error_code, address); > > return; > > } > > + if (unlikely(vma->vm_flags & VM_DEAD)) { > > + bad_area(regs, error_code, address); > > + return; > > + } > > This will have to be done for all the supported architectures, what about doing > this check in handle_mm_fault() and return VM_FAULT_SIGSEGV ? We already do have a model for that. Have a look at MMF_UNSTABLE. -- Michal Hocko SUSE Labs