Re: drivers/input/misc/iqs626a.c:1645:12: warning: stack frame size of 2560 bytes in function 'iqs626_probe'

[Jeff LaBundy <jeff@labundy.com>]

Hi Dmitry,

On Sat, Jun 05, 2021 at 09:43:46PM -0700, Dmitry Torokhov wrote:
> On Sun, Jun 06, 2021 at 12:37:43PM +0800, kernel test robot wrote:
> > Hi Jeff,
> > 
> > FYI, the error/warning still remains.
> 
> I have no idea how it happens... 
> 
> > > 1645	static int iqs626_probe(struct i2c_client *client)
> >   1646	{
> >   1647		struct iqs626_ver_info ver_info;
> 
> This is 4 bytes.
> 
> >   1648		struct iqs626_private *iqs626;
> 
> This is 4 or 8.
> 
> >   1649		int error;
> 
> And another 4. And that is it. The bloat must be coming from elsewhere.

Agreed; in fact I am suspicious if this is part of some fallout from a recent
change in Clang. There seems to be a smattering of similar warnings as in [1]
which are preceded by the same warning about __lwsync().

I see there is a patch [2] to address the issue with __lwsync(); perhaps this
is related.

[1] https://lkml.org/lkml/2021/6/6/7
[2] https://lkml.org/lkml/2021/5/28/690

> 
> >   1650	
> >   1651		iqs626 = devm_kzalloc(&client->dev, sizeof(*iqs626), GFP_KERNEL);
> >   1652		if (!iqs626)
> >   1653			return -ENOMEM;
> >   1654	
> >   1655		i2c_set_clientdata(client, iqs626);
> >   1656		iqs626->client = client;
> >   1657	
> >   1658		iqs626->regmap = devm_regmap_init_i2c(client, &iqs626_regmap_config);
> >   1659		if (IS_ERR(iqs626->regmap)) {
> >   1660			error = PTR_ERR(iqs626->regmap);
> >   1661			dev_err(&client->dev, "Failed to initialize register map: %d\n",
> >   1662				error);
> >   1663			return error;
> >   1664		}
> >   1665	
> >   1666		init_completion(&iqs626->ati_done);
> >   1667	
> >   1668		error = regmap_raw_read(iqs626->regmap, IQS626_VER_INFO, &ver_info,
> >   1669					sizeof(ver_info));
> >   1670		if (error)
> >   1671			return error;
> >   1672	
> >   1673		if (ver_info.prod_num != IQS626_VER_INFO_PROD_NUM) {
> >   1674			dev_err(&client->dev, "Unrecognized product number: 0x%02X\n",
> >   1675				ver_info.prod_num);
> >   1676			return -EINVAL;
> >   1677		}
> >   1678	
> >   1679		error = iqs626_parse_prop(iqs626);
> >   1680		if (error)
> >   1681			return error;
> >   1682	
> >   1683		error = iqs626_input_init(iqs626);
> >   1684		if (error)
> >   1685			return error;
> >   1686	
> >   1687		error = devm_request_threaded_irq(&client->dev, client->irq,
> >   1688						  NULL, iqs626_irq, IRQF_ONESHOT,
> >   1689						  client->name, iqs626);
> >   1690		if (error) {
> >   1691			dev_err(&client->dev, "Failed to request IRQ: %d\n", error);
> >   1692			return error;
> >   1693		}
> >   1694	
> >   1695		if (!wait_for_completion_timeout(&iqs626->ati_done,
> >   1696						 msecs_to_jiffies(2000))) {
> >   1697			dev_err(&client->dev, "Failed to complete ATI\n");
> >   1698			return -ETIMEDOUT;
> >   1699		}
> >   1700	
> >   1701		/*
> >   1702		 * The keypad may include one or more switches and is not registered
> >   1703		 * until ATI is complete and the initial switch states are read.
> >   1704		 */
> >   1705		error = input_register_device(iqs626->keypad);
> >   1706		if (error)
> >   1707			dev_err(&client->dev, "Failed to register keypad: %d\n", error);
> >   1708	
> >   1709		return error;
> >   1710	}
> >   1711	
> 
> Thanks.
> 
> -- 
> Dmitry

Kind regards,
Jeff LaBundy