From: Mark Langsdorf <mlangsdo@redhat.com>
To: Mark Salter <msalter@redhat.com>, David Miller <davem@davemloft.net>
Cc: David Daney <ddaney.cavm@gmail.com>,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
f.fainelli@gmail.com, buytenh@wantstofly.org,
grant.likely@secretlab.ca
Subject: Re: [PATCH] phylib: fix device deletion order in mdiobus_unregister()
Date: Tue, 01 Sep 2015 09:07:12 -0500 [thread overview]
Message-ID: <55E5B110.5080704@redhat.com> (raw)
In-Reply-To: <1441114565-2340-1-git-send-email-msalter@redhat.com>
On 09/01/2015 08:36 AM, Mark Salter wrote:
> 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:
> [<fffffe000009739c>] dump_backtrace+0x0/0x170
> [<fffffe000009752c>] show_stack+0x20/0x2c
> [<fffffe00007436f0>] dump_stack+0x78/0x9c
> [<fffffe00000c2cb4>] warn_slowpath_common+0xa0/0xd8
> [<fffffe00000c2d60>] warn_slowpath_fmt+0x74/0x88
> [<fffffe0000293d3c>] sysfs_remove_group+0x9c/0xa4
> [<fffffe00004a8bac>] dpm_sysfs_remove+0x5c/0x70
> [<fffffe000049b388>] device_del+0x44/0x208
> [<fffffe000049b578>] device_unregister+0x2c/0x7c
> [<fffffe000050dc68>] mdiobus_unregister+0x48/0x94
> [<fffffe000052afd0>] xgene_enet_mdio_remove+0x28/0x44
> [<fffffe000052d3f0>] xgene_enet_remove+0xd0/0xd8
> [<fffffe000052d424>] xgene_enet_shutdown+0x2c/0x3c
> [<fffffe00004a204c>] platform_drv_shutdown+0x24/0x40
> [<fffffe000049d4f4>] device_shutdown+0xf0/0x1b4
> [<fffffe00000e31ec>] kernel_restart_prepare+0x40/0x4c
> [<fffffe00000e32f8>] kernel_restart+0x1c/0x80
> [<fffffe00000e3670>] 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 <msalter@redhat.com>
> ---
Tested-by: Mark Langsdorf <mlangsdo@redhat.com>
next prev parent reply other threads:[~2015-09-01 14:07 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-09-01 13:36 [PATCH] phylib: fix device deletion order in mdiobus_unregister() Mark Salter
2015-09-01 13:55 ` Florian Fainelli
2015-09-01 14:07 ` Mark Langsdorf [this message]
2015-09-01 22:03 ` David Miller
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