From patchwork Tue Jul 10 11:35:41 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Rafael J. Wysocki" X-Patchwork-Id: 10516863 X-Patchwork-Delegate: bhelgaas@google.com Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 0D19F6054E for ; Tue, 10 Jul 2018 11:37:16 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id EC82628DCD for ; Tue, 10 Jul 2018 11:37:15 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id DD72328DCA; Tue, 10 Jul 2018 11:37:15 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00, MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=unavailable version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 7F48928DB5 for ; Tue, 10 Jul 2018 11:37:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932710AbeGJLhO (ORCPT ); Tue, 10 Jul 2018 07:37:14 -0400 Received: from cloudserver094114.home.pl ([79.96.170.134]:65436 "EHLO cloudserver094114.home.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932620AbeGJLhN (ORCPT ); Tue, 10 Jul 2018 07:37:13 -0400 Received: from 79.184.255.246.ipv4.supernova.orange.pl (79.184.255.246) (HELO aspire.rjw.lan) by serwer1319399.home.pl (79.96.170.134) with SMTP (IdeaSmtpServer 0.83) id 675df17f1068173b; Tue, 10 Jul 2018 13:37:11 +0200 From: "Rafael J. Wysocki" To: Greg Kroah-Hartman Cc: Pingfan Liu , linux-kernel@vger.kernel.org, Grygorii Strashko , Christoph Hellwig , Bjorn Helgaas , Dave Young , linux-pci@vger.kernel.org, Lukas Wunner , Linux PM , Kishon Vijay Abraham I Subject: [PATCH] driver core: Partially revert "driver core: correct device's shutdown order" Date: Tue, 10 Jul 2018 13:35:41 +0200 Message-ID: <2927655.Y1qg3UnIrE@aspire.rjw.lan> In-Reply-To: <8816662.k3KXbdkA2e@aspire.rjw.lan> References: <1530600642-25090-1-git-send-email-kernelfans@gmail.com> <8816662.k3KXbdkA2e@aspire.rjw.lan> MIME-Version: 1.0 Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Rafael J. Wysocki Commit 52cdbdd49853 (driver core: correct device's shutdown order) introduced a regression by breaking device shutdown on some systems. Namely, the devices_kset_move_last() call in really_probe() added by that commit is a mistake as it may cause parents to follow children in the devices_kset list which then causes shutdown to fail. For example, if a device has children before really_probe() is called for it (which is not uncommon), that call will cause it to be reordered after the children in the devices_kset list and the ordering of that list will not reflect the correct device shutdown order any more. Also it causes the devices_kset list to be constantly reordered until all drivers have been probed which is totally pointless overhead in the majority of cases and it only covers an issue with system shutdown, while system-wide suspend/resume potentially has the same issue on the affected platforms (which is not covered). For that reason, revert the really_probe() modifications made by commit 52cdbdd49853 which unfortunately will expose the shutdown issue the problematic commit attempted to fix (and which will have to be addressed differently and correctly in the future). The other code changes made by commit 52cdbdd49853 are useful and they need not be reverted. Fixes: 52cdbdd49853 (driver core: correct device's shutdown order) Link: https://lore.kernel.org/lkml/CAFgQCTt7VfqM=UyCnvNFxrSw8Z6cUtAi3HUwR4_xPAc03SgHjQ@mail.gmail.com/ Reported-by: Pingfan Liu Tested-by: Pingfan Liu Signed-off-by: Rafael J. Wysocki Reviewed-by: Kishon Vijay Abraham I --- This is a v2 of https://patchwork.kernel.org/patch/10511241/ under a different subject. The patch itself hasn't changed, but I rewrote the changelog (as per the Bjorn's request) and changed the subject accordingly. --- drivers/base/dd.c | 8 -------- 1 file changed, 8 deletions(-) Index: linux-pm/drivers/base/dd.c =================================================================== --- linux-pm.orig/drivers/base/dd.c +++ linux-pm/drivers/base/dd.c @@ -434,14 +434,6 @@ re_probe: goto probe_failed; } - /* - * Ensure devices are listed in devices_kset in correct order - * It's important to move Dev to the end of devices_kset before - * calling .probe, because it could be recursive and parent Dev - * should always go first - */ - devices_kset_move_last(dev); - if (dev->bus->probe) { ret = dev->bus->probe(dev); if (ret)