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 D7102ECE562 for ; Mon, 17 Sep 2018 06:20:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8C991214AB for ; Mon, 17 Sep 2018 06:20:50 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8C991214AB 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 S1728303AbeIQLqm (ORCPT ); Mon, 17 Sep 2018 07:46:42 -0400 Received: from mx1.redhat.com ([209.132.183.28]:43410 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726078AbeIQLqm (ORCPT ); Mon, 17 Sep 2018 07:46:42 -0400 Received: from smtp.corp.redhat.com (int-mx10.intmail.prod.int.phx2.redhat.com [10.5.11.25]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id CDD37307D849; Mon, 17 Sep 2018 06:20:47 +0000 (UTC) Received: from localhost.localdomain.com (ovpn-12-69.pek2.redhat.com [10.72.12.69]) by smtp.corp.redhat.com (Postfix) with ESMTP id 1DCCA2010D16; Mon, 17 Sep 2018 06:20:35 +0000 (UTC) From: Lianbo Jiang 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 Subject: [PATCH] resource: fix an error which walks through iomem resources Date: Mon, 17 Sep 2018 14:20:29 +0800 Message-Id: <20180917062029.511-1-lijiang@redhat.com> X-Scanned-By: MIMEDefang 2.84 on 10.5.11.25 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.48]); Mon, 17 Sep 2018 06:20:48 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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; -- 2.17.1