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=-6.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS 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 EDBB6C433F4 for ; Wed, 19 Sep 2018 12:59:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A211A2150F for ; Wed, 19 Sep 2018 12:59:17 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A211A2150F Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com 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 S1731783AbeISShG (ORCPT ); Wed, 19 Sep 2018 14:37:06 -0400 Received: from mx1.redhat.com ([209.132.183.28]:48962 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730876AbeISShF (ORCPT ); Wed, 19 Sep 2018 14:37:05 -0400 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id CA936C004A99; Wed, 19 Sep 2018 12:59:14 +0000 (UTC) Received: from localhost.localdomain (ovpn-12-52.pek2.redhat.com [10.72.12.52]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 30ABD1073033; Wed, 19 Sep 2018 12:58:34 +0000 (UTC) Subject: Re: [PATCH] resource: fix an error which walks through iomem resources From: lijiang To: linux-kernel@vger.kernel.org Cc: dan.j.williams@intel.com, thomas.lendacky@amd.com, akpm@linux-foundation.org, tglx@linutronix.de, bhelgaas@google.com, baiyaowei@cmss.chinamobile.com, tiwai@suse.de, bp@suse.de, brijesh.singh@amd.com, dyoung@redhat.com References: <20180917062029.511-1-lijiang@redhat.com> Message-ID: <71104ee7-88e6-aa29-dbb6-a07b66c265c4@redhat.com> Date: Wed, 19 Sep 2018 20:58:28 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <20180917062029.511-1-lijiang@redhat.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.32]); Wed, 19 Sep 2018 12:59:15 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Please ignore this patch, i have put this patch into another patches series, you can refer to the link below: https://lore.kernel.org/patchwork/patch/988431/ https://lore.kernel.org/patchwork/patch/988432/ https://lore.kernel.org/patchwork/patch/988433/ Thanks. 在 2018年09月17日 14:20, Lianbo Jiang 写道: > When we walk through iomem resources by calling walk_iomem_res_desc(), the > values of the function parameter may be modified in the while loop of __walk > _iomem_res_desc(), which will cause us to not get the desired result in some > cases. > > At present, it only restores the original value of res->end, but it doesn't > restore the original value of res->flags in the while loop of __walk_iomem > _res_desc(). Whenever the find_next_iomem_res() finds a resource and returns > the result, the original values of this resource will be modified, which might > lead to an error in the next loop. For example: > > The original value of resource flags is: res->flags=0x80000200(initial value) > > p->flags _ 0x81000200 _ _ 0x80000200 _ > / \ / \ > |________|_______A________|____|_....._|______B_________|......___| > 0 0xffffffff > (memory address ranges) > > Note: if ((p->flags & res->flags) != res->flags) continue; > > When the resource A is found, the original value of this resource flags will > be changed to 0x81000200(res->flags=0x81000200), and continue to look for the > next resource, when the loop reaches resource B, it can not get the resource B > any more(you can refer to the for loop of find_next_iomem_res()), because the > value of conditional expression will become true and will also jump the resource > B. In fact, we should get the resource A and B when we walk through the whole > tree, but it only gets the resource A, the resource B is missed. > > Signed-off-by: Lianbo Jiang > --- > kernel/resource.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/kernel/resource.c b/kernel/resource.c > index 30e1bc68503b..f5d9fc70a04c 100644 > --- a/kernel/resource.c > +++ b/kernel/resource.c > @@ -375,6 +375,7 @@ static int __walk_iomem_res_desc(struct resource *res, unsigned long desc, > int (*func)(struct resource *, void *)) > { > u64 orig_end = res->end; > + u64 orig_flags = res->flags; > int ret = -1; > > while ((res->start < res->end) && > @@ -385,6 +386,7 @@ static int __walk_iomem_res_desc(struct resource *res, unsigned long desc, > > res->start = res->end + 1; > res->end = orig_end; > + res->flags = orig_flags; > } > > return ret; >