drivers/clk/clk-renesas-pcie.c:178:31: warning: '%d' directive output may be truncated writing between 1 and 4 bytes into a region of size 2

drivers/clk/clk-renesas-pcie.c:178:31: warning: '%d' directive output may be truncated writing between 1 and 4 bytes into a region of size 2

[kernel test robot]

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head:   9528d418de4d83c7ada69314ddd8d4427b1f703a
commit: cd9a5c97dfdaeb9c8ac02e14d7ccbd445e8b5265 clk: rs9: Replace model check with bitshift from chip data
date:   1 year, 1 month ago
config: s390-randconfig-r111-20250120 (https://download.01.org/0day-ci/archive/20250120/202501200756.HycDH8wZ-lkp@intel.com/config)
compiler: s390-linux-gcc (GCC) 14.2.0
reproduce: (https://download.01.org/0day-ci/archive/20250120/202501200756.HycDH8wZ-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202501200756.HycDH8wZ-lkp@intel.com/

All warnings (new ones prefixed by >>):

   drivers/clk/clk-renesas-pcie.c: In function 'rs9_probe':
>> drivers/clk/clk-renesas-pcie.c:178:31: warning: '%d' directive output may be truncated writing between 1 and 4 bytes into a region of size 2 [-Wformat-truncation=]
     178 |         snprintf(name, 5, "DIF%d", idx);
         |                               ^~
   In function 'rs9_get_output_config',
       inlined from 'rs9_probe' at drivers/clk/clk-renesas-pcie.c:305:9:
   drivers/clk/clk-renesas-pcie.c:178:27: note: directive argument in the range [-250, 63]
     178 |         snprintf(name, 5, "DIF%d", idx);
         |                           ^~~~~~~
   drivers/clk/clk-renesas-pcie.c:178:9: note: 'snprintf' output between 5 and 8 bytes into a destination of size 5
     178 |         snprintf(name, 5, "DIF%d", idx);
         |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~


vim +178 drivers/clk/clk-renesas-pcie.c

603df193ec5174 Alexander Stein 2023-03-10  165  
892e0ddea1aa6f Marek Vasut     2022-02-26  166  static int rs9_get_output_config(struct rs9_driver_data *rs9, int idx)
892e0ddea1aa6f Marek Vasut     2022-02-26  167  {
892e0ddea1aa6f Marek Vasut     2022-02-26  168  	struct i2c_client *client = rs9->client;
603df193ec5174 Alexander Stein 2023-03-10  169  	u8 dif = rs9_calc_dif(rs9, idx);
892e0ddea1aa6f Marek Vasut     2022-02-26  170  	unsigned char name[5] = "DIF0";
892e0ddea1aa6f Marek Vasut     2022-02-26  171  	struct device_node *np;
892e0ddea1aa6f Marek Vasut     2022-02-26  172  	int ret;
892e0ddea1aa6f Marek Vasut     2022-02-26  173  	u32 sr;
892e0ddea1aa6f Marek Vasut     2022-02-26  174  
892e0ddea1aa6f Marek Vasut     2022-02-26  175  	/* Set defaults */
603df193ec5174 Alexander Stein 2023-03-10  176  	rs9->clk_dif_sr |= dif;
892e0ddea1aa6f Marek Vasut     2022-02-26  177  
892e0ddea1aa6f Marek Vasut     2022-02-26 @178  	snprintf(name, 5, "DIF%d", idx);
892e0ddea1aa6f Marek Vasut     2022-02-26  179  	np = of_get_child_by_name(client->dev.of_node, name);
892e0ddea1aa6f Marek Vasut     2022-02-26  180  	if (!np)
892e0ddea1aa6f Marek Vasut     2022-02-26  181  		return 0;
892e0ddea1aa6f Marek Vasut     2022-02-26  182  
892e0ddea1aa6f Marek Vasut     2022-02-26  183  	/* Output clock slew rate */
892e0ddea1aa6f Marek Vasut     2022-02-26  184  	ret = of_property_read_u32(np, "renesas,slew-rate", &sr);
892e0ddea1aa6f Marek Vasut     2022-02-26  185  	of_node_put(np);
892e0ddea1aa6f Marek Vasut     2022-02-26  186  	if (!ret) {
892e0ddea1aa6f Marek Vasut     2022-02-26  187  		if (sr == 2000000) {		/* 2V/ns */
603df193ec5174 Alexander Stein 2023-03-10  188  			rs9->clk_dif_sr &= ~dif;
892e0ddea1aa6f Marek Vasut     2022-02-26  189  		} else if (sr == 3000000) {	/* 3V/ns (default) */
603df193ec5174 Alexander Stein 2023-03-10  190  			rs9->clk_dif_sr |= dif;
892e0ddea1aa6f Marek Vasut     2022-02-26  191  		} else
892e0ddea1aa6f Marek Vasut     2022-02-26  192  			ret = dev_err_probe(&client->dev, -EINVAL,
892e0ddea1aa6f Marek Vasut     2022-02-26  193  					    "Invalid renesas,slew-rate value\n");
892e0ddea1aa6f Marek Vasut     2022-02-26  194  	}
892e0ddea1aa6f Marek Vasut     2022-02-26  195  
892e0ddea1aa6f Marek Vasut     2022-02-26  196  	return ret;
892e0ddea1aa6f Marek Vasut     2022-02-26  197  }
892e0ddea1aa6f Marek Vasut     2022-02-26  198  

:::::: The code at line 178 was first introduced by commit
:::::: 892e0ddea1aa6f70b68cb2dd8e16bf271e20e72f clk: rs9: Add Renesas 9-series PCIe clock generator driver

:::::: TO: Marek Vasut <marex@denx.de>
:::::: CC: Stephen Boyd <sboyd@kernel.org>

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

Re: drivers/clk/clk-renesas-pcie.c:178:31: warning: '%d' directive output may be truncated writing between 1 and 4 bytes into a region of size 2

[Marek Vasut]

On 1/20/25 12:45 AM, kernel test robot wrote:
> tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
> head:   9528d418de4d83c7ada69314ddd8d4427b1f703a
> commit: cd9a5c97dfdaeb9c8ac02e14d7ccbd445e8b5265 clk: rs9: Replace model check with bitshift from chip data
> date:   1 year, 1 month ago
> config: s390-randconfig-r111-20250120 (https://download.01.org/0day-ci/archive/20250120/202501200756.HycDH8wZ-lkp@intel.com/config)
> compiler: s390-linux-gcc (GCC) 14.2.0
> reproduce: (https://download.01.org/0day-ci/archive/20250120/202501200756.HycDH8wZ-lkp@intel.com/reproduce)
> 
> If you fix the issue in a separate patch/commit (i.e. not just a new version of
> the same patch/commit), kindly add following tags
> | Reported-by: kernel test robot <lkp@intel.com>
> | Closes: https://lore.kernel.org/oe-kbuild-all/202501200756.HycDH8wZ-lkp@intel.com/
> 
> All warnings (new ones prefixed by >>):
> 
>     drivers/clk/clk-renesas-pcie.c: In function 'rs9_probe':
>>> drivers/clk/clk-renesas-pcie.c:178:31: warning: '%d' directive output may be truncated writing between 1 and 4 bytes into a region of size 2 [-Wformat-truncation=]
>       178 |         snprintf(name, 5, "DIF%d", idx);
>           |                               ^~
>     In function 'rs9_get_output_config',
>         inlined from 'rs9_probe' at drivers/clk/clk-renesas-pcie.c:305:9:
>     drivers/clk/clk-renesas-pcie.c:178:27: note: directive argument in the range [-250, 63]
>       178 |         snprintf(name, 5, "DIF%d", idx);
>           |                           ^~~~~~~
>     drivers/clk/clk-renesas-pcie.c:178:9: note: 'snprintf' output between 5 and 8 bytes into a destination of size 5
>       178 |         snprintf(name, 5, "DIF%d", idx);
>           |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> 
I can extend the name variable to length 8 to mitigate this warning, but 
there is some 8 DIF outputs maximum on this hardware, so it is known 
this %d field would not be longer than 1 decimal number. Shall I send 
such a patch ?

Re: drivers/clk/clk-renesas-pcie.c:178:31: warning: '%d' directive output may be truncated writing between 1 and 4 bytes into a region of size 2

[Geert Uytterhoeven]

On Mon, Jan 20, 2025 at 8:19 AM Marek Vasut <marek.vasut@mailbox.org> wrote:
> On 1/20/25 12:45 AM, kernel test robot wrote:
> > tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
> > head:   9528d418de4d83c7ada69314ddd8d4427b1f703a
> > commit: cd9a5c97dfdaeb9c8ac02e14d7ccbd445e8b5265 clk: rs9: Replace model check with bitshift from chip data
> > date:   1 year, 1 month ago
> > config: s390-randconfig-r111-20250120 (https://download.01.org/0day-ci/archive/20250120/202501200756.HycDH8wZ-lkp@intel.com/config)
> > compiler: s390-linux-gcc (GCC) 14.2.0
> > reproduce: (https://download.01.org/0day-ci/archive/20250120/202501200756.HycDH8wZ-lkp@intel.com/reproduce)
> >
> > If you fix the issue in a separate patch/commit (i.e. not just a new version of
> > the same patch/commit), kindly add following tags
> > | Reported-by: kernel test robot <lkp@intel.com>
> > | Closes: https://lore.kernel.org/oe-kbuild-all/202501200756.HycDH8wZ-lkp@intel.com/
> >
> > All warnings (new ones prefixed by >>):
> >
> >     drivers/clk/clk-renesas-pcie.c: In function 'rs9_probe':
> >>> drivers/clk/clk-renesas-pcie.c:178:31: warning: '%d' directive output may be truncated writing between 1 and 4 bytes into a region of size 2 [-Wformat-truncation=]
> >       178 |         snprintf(name, 5, "DIF%d", idx);
> >           |                               ^~
> >     In function 'rs9_get_output_config',
> >         inlined from 'rs9_probe' at drivers/clk/clk-renesas-pcie.c:305:9:
> >     drivers/clk/clk-renesas-pcie.c:178:27: note: directive argument in the range [-250, 63]

I'm wondering how the compiler arrives at this range?

> >       178 |         snprintf(name, 5, "DIF%d", idx);
> >           |                           ^~~~~~~
> >     drivers/clk/clk-renesas-pcie.c:178:9: note: 'snprintf' output between 5 and 8 bytes into a destination of size 5
> >       178 |         snprintf(name, 5, "DIF%d", idx);
> >           |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> >
> I can extend the name variable to length 8 to mitigate this warning, but
> there is some 8 DIF outputs maximum on this hardware, so it is known
> this %d field would not be longer than 1 decimal number. Shall I send
> such a patch ?

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds