[stable:linux-5.4.y 2861/5186] include/linux/sunrpc/xdr.h:539:17: error: comparison is always false due to limited range of data type

[kernel test robot]

Hi Dan,

FYI, the error/warning still remains.

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable.git linux-5.4.y
head:   684cc17be897de3b0fd2e5a021a702f68046d9fe
commit: ce1aa09cc14ed625104acc2d487bd92b9a88efe2 [2861/5186] NFSD: prevent integer overflow on 32 bit systems
config: sparc64-randconfig-r003-20220823 (https://download.01.org/0day-ci/archive/20220825/202208252033.POQoHYcN-lkp@xxxxxxxxx/config)
compiler: sparc64-linux-gcc (GCC) 12.1.0
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
        # https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable.git/commit/?id=ce1aa09cc14ed625104acc2d487bd92b9a88efe2
        git remote add stable https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable.git
        git fetch --no-tags stable linux-5.4.y
        git checkout ce1aa09cc14ed625104acc2d487bd92b9a88efe2
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross W=1 O=build_dir ARCH=sparc64 SHELL=/bin/bash arch/sparc/kernel/

If you fix the issue, kindly add following tag where applicable
Reported-by: kernel test robot <lkp@xxxxxxxxx>

All errors (new ones prefixed by >>):

   In file included from include/linux/sunrpc/sched.h:19,
                    from include/linux/sunrpc/auth.h:15,
                    from include/linux/nfs_fs.h:31,
                    from arch/sparc/kernel/sys_sparc32.c:25:
   include/linux/sunrpc/xdr.h: In function 'xdr_stream_decode_uint32_array':
>> include/linux/sunrpc/xdr.h:539:17: error: comparison is always false due to limited range of data type [-Werror=type-limits]
     539 |         if (len > SIZE_MAX / sizeof(*p))
         |                 ^
   cc1: all warnings being treated as errors

Kconfig warnings: (for reference only)
   WARNING: unmet direct dependencies detected for FRAME_POINTER
   Depends on [n]: DEBUG_KERNEL [=y] && (M68K || UML || SUPERH) || ARCH_WANT_FRAME_POINTERS [=n] || MCOUNT [=n]
   Selected by [y]:
   - LOCKDEP [=y] && DEBUG_KERNEL [=y] && LOCK_DEBUGGING_SUPPORT [=y] && !MIPS && !PPC && !ARM && !S390 && !MICROBLAZE && !ARC && !X86


vim +539 include/linux/sunrpc/xdr.h

   517	
   518	/**
   519	 * xdr_stream_decode_uint32_array - Decode variable length array of integers
   520	 * @xdr: pointer to xdr_stream
   521	 * @array: location to store the integer array or NULL
   522	 * @array_size: number of elements to store
   523	 *
   524	 * Return values:
   525	 *   On success, returns number of elements stored in @array
   526	 *   %-EBADMSG on XDR buffer overflow
   527	 *   %-EMSGSIZE if the size of the array exceeds @array_size
   528	 */
   529	static inline ssize_t
   530	xdr_stream_decode_uint32_array(struct xdr_stream *xdr,
   531			__u32 *array, size_t array_size)
   532	{
   533		__be32 *p;
   534		__u32 len;
   535		ssize_t retval;
   536	
   537		if (unlikely(xdr_stream_decode_u32(xdr, &len) < 0))
   538			return -EBADMSG;
 > 539		if (len > SIZE_MAX / sizeof(*p))
   540			return -EBADMSG;
   541		p = xdr_inline_decode(xdr, len * sizeof(*p));
   542		if (unlikely(!p))
   543			return -EBADMSG;
   544		if (array == NULL)
   545			return len;
   546		if (len <= array_size) {
   547			if (len < array_size)
   548				memset(array+len, 0, (array_size-len)*sizeof(*array));
   549			array_size = len;
   550			retval = len;
   551		} else
   552			retval = -EMSGSIZE;
   553		for (; array_size > 0; p++, array++, array_size--)
   554			*array = be32_to_cpup(p);
   555		return retval;
   556	}
   557	#endif /* __KERNEL__ */
   558	

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