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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 BD152C3A5A2 for ; Tue, 3 Sep 2019 16:31:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9645423789 for ; Tue, 3 Sep 2019 16:31:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1567528307; bh=rkqcKpaAl5k6JghFCig/QH6Jn5EnL2Ec9Nqq3twxghg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=bQ6vM4p5AvMmxchU+fdG0mQEaUrLKkTEHSnfs5FMfB/wvNWb+yaynnv4cgjQHANX7 rli0iaCwXV9fJL6p5oXQ6zO4bjdvoPhJWJpXQ7QlvTeyxlW/ZjBDMqtMPFivRiuWna UkPVkfKAOmCHGipP6T8TfaBTDmJ+6sZrUYr0MrOg= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728967AbfICQbq (ORCPT ); Tue, 3 Sep 2019 12:31:46 -0400 Received: from mail.kernel.org ([198.145.29.99]:54824 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731171AbfICQbn (ORCPT ); Tue, 3 Sep 2019 12:31:43 -0400 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 2A440238CE; Tue, 3 Sep 2019 16:31:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1567528302; bh=rkqcKpaAl5k6JghFCig/QH6Jn5EnL2Ec9Nqq3twxghg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=k3PTu+yW8jvolbjaLbhehZ0NndWWQCLxXzEFaQpFkiuf9mXRf+CxOLYTkRmqDcZVs EwtDWOy8JreTgZjIUZAKDGq4SmuYphA6YPRj+IRM+MooR40eCYQ4tb+YtGJbv69MFf ++jXv5EXXoMp1qFj+KCqM9jagtikzWdPwWHF2YpU= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Nadav Amit , Andrew Morton , Dan Williams , Borislav Petkov , Toshi Kani , Peter Zijlstra , Dave Hansen , Bjorn Helgaas , Ingo Molnar , Linus Torvalds , Sasha Levin Subject: [PATCH AUTOSEL 4.19 144/167] resource: fix locking in find_next_iomem_res() Date: Tue, 3 Sep 2019 12:24:56 -0400 Message-Id: <20190903162519.7136-144-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190903162519.7136-1-sashal@kernel.org> References: <20190903162519.7136-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Nadav Amit [ Upstream commit 49f17c26c123b60fd1c74629eef077740d16ffc2 ] Since resources can be removed, locking should ensure that the resource is not removed while accessing it. However, find_next_iomem_res() does not hold the lock while copying the data of the resource. Keep holding the lock while the data is copied. While at it, change the return value to a more informative value. It is disregarded by the callers. [akpm@linux-foundation.org: fix find_next_iomem_res() documentation] Link: http://lkml.kernel.org/r/20190613045903.4922-2-namit@vmware.com Fixes: ff3cc952d3f00 ("resource: Add remove_resource interface") Signed-off-by: Nadav Amit Reviewed-by: Andrew Morton Reviewed-by: Dan Williams Cc: Borislav Petkov Cc: Toshi Kani Cc: Peter Zijlstra Cc: Dave Hansen Cc: Bjorn Helgaas Cc: Ingo Molnar Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin --- kernel/resource.c | 20 ++++++++++---------- 1 file changed, 10 insertions(+), 10 deletions(-) diff --git a/kernel/resource.c b/kernel/resource.c index 38b8d11c9eaf4..bce773cc5e416 100644 --- a/kernel/resource.c +++ b/kernel/resource.c @@ -325,7 +325,7 @@ EXPORT_SYMBOL(release_resource); * * If a resource is found, returns 0 and *res is overwritten with the part * of the resource that's within [start..end]; if none is found, returns - * -1. + * -ENODEV. Returns -EINVAL for invalid parameters. * * This function walks the whole tree and not just first level children * unless @first_level_children_only is true. @@ -359,16 +359,16 @@ static int find_next_iomem_res(resource_size_t start, resource_size_t end, break; } + if (p) { + /* copy data */ + res->start = max(start, p->start); + res->end = min(end, p->end); + res->flags = p->flags; + res->desc = p->desc; + } + read_unlock(&resource_lock); - if (!p) - return -1; - - /* copy data */ - res->start = max(start, p->start); - res->end = min(end, p->end); - res->flags = p->flags; - res->desc = p->desc; - return 0; + return p ? 0 : -ENODEV; } static int __walk_iomem_res_desc(resource_size_t start, resource_size_t end, -- 2.20.1