Re: drivers/input/misc/iqs626a.c:1645:12: warning: stack frame size (2448) exceeds limit (2048) in 'iqs626_probe'

[Jeff LaBundy <jeff@labundy.com>]

Hi all,

On Fri, Nov 26, 2021 at 10:27:30PM +0800, kernel test robot wrote:
> Hi Jeff,
> 
> FYI, the error/warning still remains.
> 
> tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
> head:   a4849f6000e29235a2707f22e39da6b897bb9543
> commit: f1d2809de97adc422967b6de59f0f6199769eb93 Input: Add support for Azoteq IQS626A
> date:   8 months ago
> config: mips-randconfig-r013-20211124 (https://download.01.org/0day-ci/archive/20211126/202111262250.Y0l0olCY-lkp@intel.com/config)
> compiler: clang version 14.0.0 (https://github.com/llvm/llvm-project 67a1c45def8a75061203461ab0060c75c864df1c)
> reproduce (this is a W=1 build):
>         wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
>         chmod +x ~/bin/make.cross
>         # install mips cross compiling tool for clang build
>         # apt-get install binutils-mips-linux-gnu
>         # https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=f1d2809de97adc422967b6de59f0f6199769eb93
>         git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
>         git fetch --no-tags linus master
>         git checkout f1d2809de97adc422967b6de59f0f6199769eb93
>         # save the config file to linux build tree
>         COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 ARCH=mips 
> 
> If you fix the issue, kindly add following tag as appropriate
> Reported-by: kernel test robot <lkp@intel.com>

I was finally able to reproduce this report with the same steps; the
compiler appears to be inlining several functions called from inside
a for loop. I have posted a workaround in [1].

> 
> All warnings (new ones prefixed by >>):
> 
> >> drivers/input/misc/iqs626a.c:1645:12: warning: stack frame size (2448) exceeds limit (2048) in 'iqs626_probe' [-Wframe-larger-than]
>    static int iqs626_probe(struct i2c_client *client)
>               ^
>    1 warning generated.
>    Assembler messages:
>    Warning: a different -march was already specified, is now octeon
> 
> 
> vim +/iqs626_probe +1645 drivers/input/misc/iqs626a.c
> 
>   1644	
> > 1645	static int iqs626_probe(struct i2c_client *client)
>   1646	{
>   1647		struct iqs626_ver_info ver_info;
>   1648		struct iqs626_private *iqs626;
>   1649		int error;
>   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	
> 
> ---
> 0-DAY CI Kernel Test Service, Intel Corporation
> https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org

[1] https://patchwork.kernel.org/patch/12643273

Kind regards,
Jeff LaBundy