Regression on next (Re: [PATCH 3/3] driver: Call bus->remove instead of driver->remove)

[Ezequiel Garcia]

On 05/04/2015 03:29 AM, Sascha Hauer wrote:
> Hi Ezequiel,
> 
> On Sat, May 02, 2015 at 01:50:42PM -0300, Ezequiel Garcia wrote:
>> Hi Sascha,
>>
>> On 03/17/2015 03:25 AM, Sascha Hauer wrote:
>>> In devices_shutdown we should call the busses remove function
>>> which in turn calls the drivers remove function. Otherwise for
>>> example PCI devices never get removed since they do not have
>>> a remove function but a pcidev->remove function instead.
>>>
>>> Signed-off-by: Sascha Hauer <s.hauer at pengutronix.de>
>>> ---
>>>  drivers/base/driver.c | 4 ++--
>>>  1 file changed, 2 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/drivers/base/driver.c b/drivers/base/driver.c
>>> index 453966b..590c97c 100644
>>> --- a/drivers/base/driver.c
>>> +++ b/drivers/base/driver.c
>>> @@ -399,8 +399,8 @@ void devices_shutdown(void)
>>>  	struct device_d *dev;
>>>  
>>>  	list_for_each_entry(dev, &active, active) {
>>> -		if (dev->driver->remove)
>>> -			dev->driver->remove(dev);
>>> +		if (dev->bus->remove)
>>> +			dev->bus->remove(dev);
>>>  	}
>>>  }
>>>  
>>>
>>
>> This commit caused a regression on the Openblocks A6 board, which now freezes
>> when calling devices_shutdown. The problem is that calling bus->remove makes
>> the remove() of the PHY driver called twice.
>>
>> This happened because the mdio bus device (mdio-mvebu) was registered first,
>> and the phy0 device was be registered later, and attached to the mdio bus.
>>
>> Upon device shutdown, when iterating through the active device list,
>> the phy0 device is removed before mdio-mvebu. Then, when the mdio bus device
>> is removed, the phy0 device is removed again, here:
>>
>> mdio_bus_remove(on mdio-mvebu)
>>   mvebu_mdio_remove
>>     mdiobus_unregister
>>       unregister_device
>>         mdio_bus_remove(on phy0)
>>         
>> This is currently the case for the Kirkwood Openblocks A6 board, where a double
>> free(dev->cdev.name) in mdio_bus_remove causes a silent freeze when booting
>> Linux.
> 
> Too bad that happened. I believe the following fixes this, but I have no
> hardware to test this on. Could you give this a test? I'll delay the
> outstanding release until this is solved.
> 
> Sascha
> 
> ----------------------------8<---------------------------
> 
> From 15422e3435b0151f1b5d753b19a8578210da9d04 Mon Sep 17 00:00:00 2001
> From: Sascha Hauer <s.hauer at pengutronix.de>
> Date: Mon, 4 May 2015 08:16:20 +0200
> Subject: [PATCH] net: phy: Do not double remove phy device
> 
> This fixes: 80264a8 driver: Call bus->remove instead of driver->remove
> 
> On mvebu it happens that:
> 
> Upon device shutdown, when iterating through the active device list,
> the phy0 device is removed before mdio-mvebu. Then, when the mdio bus
> device is removed, the phy0 device is removed again, here:
> 
> mdio_bus_remove(on mdio-mvebu)
>   mvebu_mdio_remove
>     mdiobus_unregister
>       unregister_device
>         mdio_bus_remove(on phy0)
> 
> Fix this by setting the mdio busses phy_map[phy->addr] to NULL when
> unregistering the phy device, so that mdiobus_unregister no longer
> finds a valid phy_device when iterating over the busses device list.
> 
> Reported-by: Ezequiel Garcia <ezequiel at vanguardiasur.com.ar>
> Signed-off-by: Sascha Hauer <s.hauer at pengutronix.de>

Tested-by: Ezequiel Garcia <ezequiel at vanguardiasur.com.ar>

Thanks for the quick fix,
-- 
Ezequiel Garcia, VanguardiaSur
www.vanguardiasur.com.ar