From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753315AbbIANgW (ORCPT ); Tue, 1 Sep 2015 09:36:22 -0400 Received: from mx1.redhat.com ([209.132.183.28]:40870 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751141AbbIANgV (ORCPT ); Tue, 1 Sep 2015 09:36:21 -0400 From: Mark Salter To: David Miller Cc: David Daney , netdev@vger.kernel.org, linux-kernel@vger.kernel.org, f.fainelli@gmail.com, buytenh@wantstofly.org, grant.likely@secretlab.ca, Mark Salter Subject: [PATCH] phylib: fix device deletion order in mdiobus_unregister() Date: Tue, 1 Sep 2015 09:36:05 -0400 Message-Id: <1441114565-2340-1-git-send-email-msalter@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 --- drivers/net/phy/mdio_bus.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/net/phy/mdio_bus.c b/drivers/net/phy/mdio_bus.c index 46a14cb..02a4615 100644 --- a/drivers/net/phy/mdio_bus.c +++ b/drivers/net/phy/mdio_bus.c @@ -303,12 +303,12 @@ void mdiobus_unregister(struct mii_bus *bus) BUG_ON(bus->state != MDIOBUS_REGISTERED); bus->state = MDIOBUS_UNREGISTERED; - device_del(&bus->dev); for (i = 0; i < PHY_MAX_ADDR; i++) { if (bus->phy_map[i]) device_unregister(&bus->phy_map[i]->dev); bus->phy_map[i] = NULL; } + device_del(&bus->dev); } EXPORT_SYMBOL(mdiobus_unregister); -- 2.4.3