From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753814AbbIANzI (ORCPT ); Tue, 1 Sep 2015 09:55:08 -0400 Received: from mail-ob0-f169.google.com ([209.85.214.169]:35444 "EHLO mail-ob0-f169.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752761AbbIANzG (ORCPT ); Tue, 1 Sep 2015 09:55:06 -0400 Subject: Re: [PATCH] phylib: fix device deletion order in mdiobus_unregister() To: Mark Salter , David Miller References: <1441114565-2340-1-git-send-email-msalter@redhat.com> Cc: David Daney , netdev@vger.kernel.org, linux-kernel@vger.kernel.org, buytenh@wantstofly.org, grant.likely@secretlab.ca From: Florian Fainelli Message-ID: <55E5AE36.7030906@gmail.com> Date: Tue, 1 Sep 2015 06:55:02 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.2.0 MIME-Version: 1.0 In-Reply-To: <1441114565-2340-1-git-send-email-msalter@redhat.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Le 09/01/15 06:36, Mark Salter a écrit : > commit 8b63ec1837fa ("phylib: Make PHYs children of their MDIO bus, not > the bus' parent.") uncovered a problem in mdiobus_unregister() which > leads to this warning when I reboot an APM Mustang (arm64) platform: > > WARNING: CPU: 7 PID: 4239 at fs/sysfs/group.c:224 sysfs_remove_group+0xa0/0xa4() > sysfs group fffffe0000e07a10 not found for kobject 'xgene-mii-eth0:03' > ... > CPU: 7 PID: 4239 Comm: reboot Tainted: G E 4.2.0-0.18.el7.test15.aarch64 #1 > Hardware name: AppliedMicro Mustang/Mustang, BIOS 1.1.0 Aug 26 2015 > Call Trace: > [] dump_backtrace+0x0/0x170 > [] show_stack+0x20/0x2c > [] dump_stack+0x78/0x9c > [] warn_slowpath_common+0xa0/0xd8 > [] warn_slowpath_fmt+0x74/0x88 > [] sysfs_remove_group+0x9c/0xa4 > [] dpm_sysfs_remove+0x5c/0x70 > [] device_del+0x44/0x208 > [] device_unregister+0x2c/0x7c > [] mdiobus_unregister+0x48/0x94 > [] xgene_enet_mdio_remove+0x28/0x44 > [] xgene_enet_remove+0xd0/0xd8 > [] xgene_enet_shutdown+0x2c/0x3c > [] platform_drv_shutdown+0x24/0x40 > [] device_shutdown+0xf0/0x1b4 > [] kernel_restart_prepare+0x40/0x4c > [] kernel_restart+0x1c/0x80 > [] SyS_reboot+0x17c/0x250 > > The problem is that mdiobus_unregister() deletes the bus device before > unregistering the phy devices on the bus. This wasn't a problem before > because the phys were not children of the bus: > > /sys/devices/platform/APMC0D05:00/net/eth0/xgene-mii-eth0:03 > /sys/devices/platform/APMC0D05:00/net/eth0/xgene-mii-eth0 > > But now that they are: > > /sys/devices/platform/APMC0D05:00/net/eth0/xgene-mii-eth0/xgene-mii-eth0:03 > > when mdiobus_unregister deletes the bus device, the phy subdirs are > removed from sysfs also. So when the phys are unregistered afterward, > we get the warning. This patch changes the order so that phys are > unregistered before the bus device is deleted. > > Signed-off-by: Mark Salter Fixes: 8b63ec1837fa ("phylib: Make PHYs children of their MDIO bus, not the bus' parent.") Reviewed-by: Florian Fainelli Thanks! -- Florian