linux-kernel - Re: [PATCH] Input: synaptics-rmi4 - Fix error handling in I2C transport driver

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Message-ID: <74a818fc-6ebf-0514-461e-b664390c32cb@roeck-us.net>
Date:   Fri, 30 Sep 2016 20:44:23 -0700
From:   Guenter Roeck <linux@...ck-us.net>
To:     Dmitry Torokhov <dmitry.torokhov@...il.com>,
        Bjorn Andersson <bjorn.andersson@...aro.org>
Cc:     linux-input@...r.kernel.org, linux-kernel@...r.kernel.org,
        Andrew Duggan <aduggan@...aptics.com>
Subject: Re: [PATCH] Input: synaptics-rmi4 - Fix error handling in I2C
 transport driver

On 09/30/2016 04:02 PM, Dmitry Torokhov wrote:
> On Fri, Sep 30, 2016 at 03:54:03PM -0700, Dmitry Torokhov wrote:
>> On Thu, Sep 29, 2016 at 10:55:40AM -0700, Bjorn Andersson wrote:
>>> On Wed 28 Sep 17:37 PDT 2016, Guenter Roeck wrote:
>>>
>>>> Instantiating the rmi4 I2C transport driver without interrupts assigned
>>>> (for example using manual i2c instantiation from the command line)
>>>> caused the driver to fail to load, but it does not clean up its
>>>> regulator or transport device registrations. Result is a crash at a later
>>>> time, for example when rebooting the system.
>>>>
>>>> Fixes: 946c8432aab0 ("Input: synaptics-rmi4 - support regulator supplies")
>>>
>>> Sorry for that.
>>>
>>>> Fixes: fdf51604f104 ("Input: synaptics-rmi4 - add I2C transport driver")
>>>> Cc: Bjorn Andersson <bjorn.andersson@...aro.org>
>>>
>>> Reviewed-by: Bjorn Andersson <bjorn.andersson@...aro.org>
>>
>> Applied, thank you.
>
> I take it back. rmi_i2c_init_irq() uses devm* so this whole thing mixes
> up devm* and manual unregistering and unwind order is completely
> broken.
>
Oops ...

> 1. Why do we register interrupt from transport drivers and not make it
> part of rmi_register_transport_device()?

rmi_register_transport_device() doesn't take dev as parameter.

> 2. If we need to use some non-devm-ised resources we should use
> devm_add_action[_or_reset] to work these operations into devm stream.

Ok, no problem.

Guenter

>
> Thanks,
>
>>
>> It looks like we have similar issue in rmi_spi.c. Can I get another
>> patch?
>>
>>>
>>> Regards,
>>> Bjorn
>>>
>>>> Cc: Andrew Duggan <aduggan@...aptics.com>
>>>> Signed-off-by: Guenter Roeck <linux@...ck-us.net>
>>>> ---
>>>>  drivers/input/rmi4/rmi_i2c.c | 13 ++++++++++---
>>>>  1 file changed, 10 insertions(+), 3 deletions(-)
>>>>
>>>> diff --git a/drivers/input/rmi4/rmi_i2c.c b/drivers/input/rmi4/rmi_i2c.c
>>>> index 6f2e0e4f0296..d57b227ccd25 100644
>>>> --- a/drivers/input/rmi4/rmi_i2c.c
>>>> +++ b/drivers/input/rmi4/rmi_i2c.c
>>>> @@ -285,23 +285,30 @@ static int rmi_i2c_probe(struct i2c_client *client,
>>>>  	retval = rmi_set_page(rmi_i2c, 0);
>>>>  	if (retval) {
>>>>  		dev_err(&client->dev, "Failed to set page select to 0.\n");
>>>> -		return retval;
>>>> +		goto error_disable;
>>>>  	}
>>>>
>>>>  	retval = rmi_register_transport_device(&rmi_i2c->xport);
>>>>  	if (retval) {
>>>>  		dev_err(&client->dev, "Failed to register transport driver at 0x%.2X.\n",
>>>>  			client->addr);
>>>> -		return retval;
>>>> +		goto error_disable;
>>>>  	}
>>>>
>>>>  	retval = rmi_i2c_init_irq(client);
>>>>  	if (retval < 0)
>>>> -		return retval;
>>>> +		goto error_unregister;
>>>>
>>>>  	dev_info(&client->dev, "registered rmi i2c driver at %#04x.\n",
>>>>  			client->addr);
>>>>  	return 0;
>>>> +
>>>> +error_unregister:
>>>> +	rmi_unregister_transport_device(&rmi_i2c->xport);
>>>> +error_disable:
>>>> +	regulator_bulk_disable(ARRAY_SIZE(rmi_i2c->supplies),
>>>> +			       rmi_i2c->supplies);
>>>> +	return retval;
>>>>  }
>>>>
>>>>  static int rmi_i2c_remove(struct i2c_client *client)
>>>> --
>>>> 2.5.0
>>>>
>>
>> --
>> Dmitry
>