linux-kernel - Re: [PATCH v1 1/1] mtd: mtdpart: Do not supply NULL to printf()

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Message-ID: <a5d38df2-4679-9bb9-4b01-2cfa184cd1be@huawei.com>
Date: Thu, 13 Mar 2025 18:54:40 +0800
From: Zhihao Cheng <chengzhihao1@...wei.com>
To: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
CC: <linux-mtd@...ts.infradead.org>, <linux-kernel@...r.kernel.org>, Miquel
 Raynal <miquel.raynal@...tlin.com>, Richard Weinberger <richard@....at>,
	Vignesh Raghavendra <vigneshr@...com>
Subject: Re: [PATCH v1 1/1] mtd: mtdpart: Do not supply NULL to printf()

在 2025/3/13 17:09, Andy Shevchenko 写道:
> On Thu, Mar 13, 2025 at 09:24:21AM +0800, Zhihao Cheng wrote:
>> 在 2025/3/13 4:16, Andy Shevchenko 写道:
>>> Compiler is not happy about NULL being supplied as printf() parameter:
>>
>> printf -> printk? The title has the same issue.
>>>
>>> drivers/mtd/mtdpart.c:693:34: error: ‘%s’ directive argument is null [-Werror=format-overflow=]
>>>
>>> Replace that with "(null)" to fix compilation error.
> 
>> Reviewed-by: Zhihao Cheng <chengzhihao1@...wei.com>
> 
> Thank you!
> 
> But I think my approach is a hack, the best is to move this message to the
> after the follow up conditional and drop that ternary completely as we have
> already another debug message before that. So, the parser == NULL can be
> deducted from the appearance of the one and not the other one.
> 
> I'll send a v2.
> 
>>>    			if (!parser && !request_module("%s", *types))
>>>    				parser = mtd_part_parser_get(*types);
>>>    			pr_debug("%s: got parser %s\n", master->name,
>>> -				parser ? parser->name : NULL);
>>> +				parser ? parser->name : "(null)");
>>>    			if (!parser)
>>>    				continue;
> 
> (move it here)

After looking through 8e2c992b59fc("mtd: mtdpart: add debug prints to 
partition parser.") and 01f9c7240a90("mtd: partitions: factor out code 
calling parser"), I think we'd better keep the debug message before the 
condition 'if (!parser)', it is used to inform us whether we get a 
parser and which name it is. And the debug message in mtd_part_do_parse 
informs us the result of the 'parser->parse_fn'.
> 
>>>    			ret = mtd_part_do_parse(parser, master, &pparts, data);
>