Re: [PATCH bpf-next 1/5] net: checksum: move from32to16() to generic header

From: kernel test robot <lkp@intel.com>
To: Puranjay Mohan <puranjay@kernel.org>,
	Albert Ou <aou@eecs.berkeley.edu>,
	Alexei Starovoitov <ast@kernel.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Andrii Nakryiko <andrii@kernel.org>,
	bpf@vger.kernel.org, Daniel Borkmann <daniel@iogearbox.net>,
	"David S. Miller" <davem@davemloft.net>,
	Eduard Zingerman <eddyz87@gmail.com>,
	Eric Dumazet <edumazet@google.com>, Hao Luo <haoluo@google.com>,
	Helge Deller <deller@gmx.de>, Jakub Kicinski <kuba@kernel.org>,
	"James E.J. Bottomley" <James.Bottomley@hansenpartnership.com>,
	Jiri Olsa <jolsa@kernel.org>,
	John Fastabend <john.fastabend@gmail.com>,
	KP Singh <kpsingh@kernel.org>,
	linux-kernel@vger.kernel.org, linux-parisc@vger.kernel.org,
	linux-riscv@lists.infradead.org,
	Martin KaFai Lau <martin.lau@linux.dev>,
	Mykola Lysenko <mykolal@fb.com>,
	Palmer Dabbelt <palmer@dabbelt.com>,
	Paolo Abeni <pabeni@redhat.com>,
	Paul Walmsley <paul.walmsley@sifive.com>,
	Puranjay Mohan <puranjay12@gmail.com>,
	Shuah Khan <skhan@linuxfoundation.org>,
	Song Liu <song@kernel.org>, Stanislav Fomichev <sdf@fomichev.me>
Cc: oe-kbuild-all@lists.linux.dev,
	Linux Memory Management List <linux-mm@kvack.org>,
	netdev@vger.kernel.org
Subject: Re: [PATCH bpf-next 1/5] net: checksum: move from32to16() to generic header
Date: Tue, 22 Oct 2024 21:50:28 +0800	[thread overview]
Message-ID: <202410222149.3FVJFYYy-lkp@intel.com> (raw)
In-Reply-To: <20241021122112.101513-2-puranjay@kernel.org>

Hi Puranjay,

kernel test robot noticed the following build warnings:

[auto build test WARNING on bpf-next/master]

url:    https://github.com/intel-lab-lkp/linux/commits/Puranjay-Mohan/net-checksum-move-from32to16-to-generic-header/20241021-202707
base:   https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git master
patch link:    https://lore.kernel.org/r/20241021122112.101513-2-puranjay%40kernel.org
patch subject: [PATCH bpf-next 1/5] net: checksum: move from32to16() to generic header
config: x86_64-randconfig-122-20241022 (https://download.01.org/0day-ci/archive/20241022/202410222149.3FVJFYYy-lkp@intel.com/config)
compiler: gcc-12 (Debian 12.2.0-14) 12.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20241022/202410222149.3FVJFYYy-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/202410222149.3FVJFYYy-lkp@intel.com/

sparse warnings: (new ones prefixed by >>)
>> lib/checksum.c:84:34: sparse: sparse: incorrect type in argument 1 (different base types) @@     expected restricted __wsum [usertype] sum @@     got unsigned int [assigned] result @@
   lib/checksum.c:84:34: sparse:     expected restricted __wsum [usertype] sum
   lib/checksum.c:84:34: sparse:     got unsigned int [assigned] result
>> lib/checksum.c:84:16: sparse: sparse: incorrect type in assignment (different base types) @@     expected unsigned int [assigned] result @@     got restricted __sum16 @@
   lib/checksum.c:84:16: sparse:     expected unsigned int [assigned] result
   lib/checksum.c:84:16: sparse:     got restricted __sum16

vim +84 lib/checksum.c

    35	
    36	#ifndef do_csum
    37	static unsigned int do_csum(const unsigned char *buff, int len)
    38	{
    39		int odd;
    40		unsigned int result = 0;
    41	
    42		if (len <= 0)
    43			goto out;
    44		odd = 1 & (unsigned long) buff;
    45		if (odd) {
    46	#ifdef __LITTLE_ENDIAN
    47			result += (*buff << 8);
    48	#else
    49			result = *buff;
    50	#endif
    51			len--;
    52			buff++;
    53		}
    54		if (len >= 2) {
    55			if (2 & (unsigned long) buff) {
    56				result += *(unsigned short *) buff;
    57				len -= 2;
    58				buff += 2;
    59			}
    60			if (len >= 4) {
    61				const unsigned char *end = buff + ((unsigned)len & ~3);
    62				unsigned int carry = 0;
    63				do {
    64					unsigned int w = *(unsigned int *) buff;
    65					buff += 4;
    66					result += carry;
    67					result += w;
    68					carry = (w > result);
    69				} while (buff < end);
    70				result += carry;
    71				result = (result & 0xffff) + (result >> 16);
    72			}
    73			if (len & 2) {
    74				result += *(unsigned short *) buff;
    75				buff += 2;
    76			}
    77		}
    78		if (len & 1)
    79	#ifdef __LITTLE_ENDIAN
    80			result += *buff;
    81	#else
    82			result += (*buff << 8);
    83	#endif
  > 84		result = csum_from32to16(result);
    85		if (odd)
    86			result = ((result >> 8) & 0xff) | ((result & 0xff) << 8);
    87	out:
    88		return result;
    89	}
    90	#endif
    91	

-- 
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https://github.com/intel/lkp-tests/wiki