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=-18.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 97330C43381 for ; Thu, 21 Jan 2021 17:52:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 69A0221973 for ; Thu, 21 Jan 2021 17:52:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389242AbhAURvp (ORCPT ); Thu, 21 Jan 2021 12:51:45 -0500 Received: from mail.kernel.org ([198.145.29.99]:52550 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389123AbhAURrm (ORCPT ); Thu, 21 Jan 2021 12:47:42 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 6DAED21973; Thu, 21 Jan 2021 17:46:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1611251218; bh=5/CpjNzCYUvdit+J2tPaf4hrd9eu5NYoBJ0rK8Zuz7w=; h=Subject:To:From:Date:From; b=M5CxnplAuS91w4QAo5SCFrHLPErgOirjiEmElPE2p6PqCoGYDLYQJ2h/gAv0CLmDu Q6/iz9Cfa1J7C5weKbm9YcXnNIHFZRIGUQqOrm/l/z3SvkhUwesaXHJ8hnO9nn+18f qvHHh3yq/EwOQlEqvhfwNfr6vvnWbSKm89Rb0Yxk= Subject: patch "driver core: Extend device_is_dependent()" added to driver-core-linus To: rafael.j.wysocki@intel.com, gregkh@linuxfoundation.org, saravanak@google.com, stable@vger.kernel.org, stephan@gerhold.net From: Date: Thu, 21 Jan 2021 18:46:55 +0100 Message-ID: <16112512152956@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org This is a note to let you know that I've just added the patch titled driver core: Extend device_is_dependent() to my driver-core git tree which can be found at git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core.git in the driver-core-linus branch. The patch will show up in the next release of the linux-next tree (usually sometime within the next 24 hours during the week.) The patch will hopefully also be merged in Linus's tree for the next -rc kernel release. If you have any questions about this process, please let me know. >From 3d1cf435e201d1fd63e4346b141881aed086effd Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Fri, 15 Jan 2021 19:30:51 +0100 Subject: driver core: Extend device_is_dependent() If the device passed as the target (second argument) to device_is_dependent() is not completely registered (that is, it has been initialized, but not added yet), but the parent pointer of it is set, it may be missing from the list of the parent's children and device_for_each_child() called by device_is_dependent() cannot be relied on to catch that dependency. For this reason, modify device_is_dependent() to check the ancestors of the target device by following its parent pointer in addition to the device_for_each_child() walk. Fixes: 9ed9895370ae ("driver core: Functional dependencies tracking support") Reported-by: Stephan Gerhold Tested-by: Stephan Gerhold Reviewed-by: Saravana Kannan Signed-off-by: Rafael J. Wysocki Link: https://lore.kernel.org/r/17705994.d592GUb2YH@kreacher Cc: stable Signed-off-by: Greg Kroah-Hartman --- drivers/base/core.c | 17 ++++++++++++++++- 1 file changed, 16 insertions(+), 1 deletion(-) diff --git a/drivers/base/core.c b/drivers/base/core.c index 25e08e5f40bd..3819fd012e27 100644 --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -208,6 +208,16 @@ int device_links_read_lock_held(void) #endif #endif /* !CONFIG_SRCU */ +static bool device_is_ancestor(struct device *dev, struct device *target) +{ + while (target->parent) { + target = target->parent; + if (dev == target) + return true; + } + return false; +} + /** * device_is_dependent - Check if one device depends on another one * @dev: Device to check dependencies for. @@ -221,7 +231,12 @@ int device_is_dependent(struct device *dev, void *target) struct device_link *link; int ret; - if (dev == target) + /* + * The "ancestors" check is needed to catch the case when the target + * device has not been completely initialized yet and it is still + * missing from the list of children of its parent device. + */ + if (dev == target || device_is_ancestor(dev, target)) return 1; ret = device_for_each_child(dev, target, device_is_dependent); -- 2.30.0