Re: [PATCH] drm/bridge: lt9611uxc: support displays with up to 4 EDID blocks

[kernel test robot <lkp@intel.com>]

Hi,

kernel test robot noticed the following build errors:

[auto build test ERROR on 4c26e162947f91aa78ba57dd4fddd38fc80e7d60]

url:    https://github.com/intel-lab-lkp/linux/commits/vishnu-saini-oss-qualcomm-com/drm-bridge-lt9611uxc-support-displays-with-up-to-4-EDID-blocks/20260518-021632
base:   4c26e162947f91aa78ba57dd4fddd38fc80e7d60
patch link:    https://lore.kernel.org/r/20260517-lt9611usc_edid34_misc_next-v1-1-5e2fd8c6399b%40oss.qualcomm.com
patch subject: [PATCH] drm/bridge: lt9611uxc: support displays with up to 4 EDID blocks
config: i386-randconfig-014-20260518 (https://download.01.org/0day-ci/archive/20260518/202605180800.luZQCJZK-lkp@intel.com/config)
compiler: gcc-14 (Debian 14.2.0-19) 14.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260518/202605180800.luZQCJZK-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/202605180800.luZQCJZK-lkp@intel.com/

All errors (new ones prefixed by >>):

   In file included from include/linux/string.h:386,
                    from include/linux/bitmap.h:13,
                    from include/linux/cpumask.h:11,
                    from arch/x86/include/asm/paravirt.h:19,
                    from arch/x86/include/asm/irqflags.h:100,
                    from include/linux/irqflags.h:18,
                    from include/linux/spinlock.h:59,
                    from include/linux/mmzone.h:8,
                    from include/linux/gfp.h:7,
                    from include/linux/firmware.h:8,
                    from drivers/gpu/drm/bridge/lontium-lt9611uxc.c:7:
   In function 'memcmp',
       inlined from 'lt9611uxc_get_edid_block' at drivers/gpu/drm/bridge/lontium-lt9611uxc.c:454:23:
>> include/linux/fortify-string.h:719:25: error: call to '__read_overflow2' declared with attribute error: detected read beyond size of object (2nd parameter)
     719 |                         __read_overflow2();
         |                         ^~~~~~~~~~~~~~~~~~


vim +/__read_overflow2 +719 include/linux/fortify-string.h

a28a6e860c6cf23 Francis Laniel 2021-02-25  708  
92df138a8d663ce Kees Cook      2022-02-08  709  __FORTIFY_INLINE __diagnose_as(__builtin_memcmp, 1, 2, 3)
281d0c962752fb4 Kees Cook      2022-02-08  710  int memcmp(const void * const POS0 p, const void * const POS0 q, __kernel_size_t size)
a28a6e860c6cf23 Francis Laniel 2021-02-25  711  {
21a2c74b0a2a784 Kees Cook      2023-04-07  712  	const size_t p_size = __struct_size(p);
21a2c74b0a2a784 Kees Cook      2023-04-07  713  	const size_t q_size = __struct_size(q);
a28a6e860c6cf23 Francis Laniel 2021-02-25  714  
a28a6e860c6cf23 Francis Laniel 2021-02-25  715  	if (__builtin_constant_p(size)) {
fa35198f39571bb Kees Cook      2022-09-19  716  		if (__compiletime_lessthan(p_size, size))
a28a6e860c6cf23 Francis Laniel 2021-02-25  717  			__read_overflow();
fa35198f39571bb Kees Cook      2022-09-19  718  		if (__compiletime_lessthan(q_size, size))
a28a6e860c6cf23 Francis Laniel 2021-02-25 @719  			__read_overflow2();
a28a6e860c6cf23 Francis Laniel 2021-02-25  720  	}
3d965b33e40d973 Kees Cook      2023-04-07  721  	if (p_size < size)
3d965b33e40d973 Kees Cook      2023-04-07  722  		fortify_panic(FORTIFY_FUNC_memcmp, FORTIFY_READ, p_size, size, INT_MIN);
3d965b33e40d973 Kees Cook      2023-04-07  723  	else if (q_size < size)
3d965b33e40d973 Kees Cook      2023-04-07  724  		fortify_panic(FORTIFY_FUNC_memcmp, FORTIFY_READ, q_size, size, INT_MIN);
a28a6e860c6cf23 Francis Laniel 2021-02-25  725  	return __underlying_memcmp(p, q, size);
a28a6e860c6cf23 Francis Laniel 2021-02-25  726  }
a28a6e860c6cf23 Francis Laniel 2021-02-25  727  

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