Re: [PATCH net v2] mctp i2c: handle NULL header address

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

Hi Matt,

kernel test robot noticed the following build warnings:

[auto build test WARNING on cb560795c8c2ceca1d36a95f0d1b2eafc4074e37]

url:    https://github.com/intel-lab-lkp/linux/commits/Matt-Johnston/mctp-i2c-handle-NULL-header-address/20241021-123741
base:   cb560795c8c2ceca1d36a95f0d1b2eafc4074e37
patch link:    https://lore.kernel.org/r/20241021-mctp-i2c-null-dest-v2-1-4503e478517c%40codeconstruct.com.au
patch subject: [PATCH net v2] mctp i2c: handle NULL header address
config: arc-allmodconfig (https://download.01.org/0day-ci/archive/20241022/202410220730.90gh2nXQ-lkp@intel.com/config)
compiler: arceb-elf-gcc (GCC) 13.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20241022/202410220730.90gh2nXQ-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/202410220730.90gh2nXQ-lkp@intel.com/

All warnings (new ones prefixed by >>):

   drivers/net/mctp/mctp-i2c.c: In function 'mctp_i2c_header_create':
>> drivers/net/mctp/mctp-i2c.c:599:23: warning: assignment to 'u8' {aka 'unsigned char'} from 'const unsigned char *' makes integer from pointer without a cast [-Wint-conversion]
     599 |                 llsrc = dev->dev_addr;
         |                       ^

Kconfig warnings: (for reference only)
   WARNING: unmet direct dependencies detected for GET_FREE_REGION
   Depends on [n]: SPARSEMEM [=n]
   Selected by [m]:
   - RESOURCE_KUNIT_TEST [=m] && RUNTIME_TESTING_MENU [=y] && KUNIT [=m]


vim +599 drivers/net/mctp/mctp-i2c.c

   579	
   580	static int mctp_i2c_header_create(struct sk_buff *skb, struct net_device *dev,
   581					  unsigned short type, const void *daddr,
   582					  const void *saddr, unsigned int len)
   583	{
   584		struct mctp_i2c_hdr *hdr;
   585		struct mctp_hdr *mhdr;
   586		u8 lldst, llsrc;
   587	
   588		if (len > MCTP_I2C_MAXMTU)
   589			return -EMSGSIZE;
   590	
   591		if (daddr)
   592			lldst = *((u8 *)daddr);
   593		else
   594			return -EINVAL;
   595	
   596		if (saddr)
   597			llsrc = *((u8 *)saddr);
   598		else
 > 599			llsrc = dev->dev_addr;
   600	
   601		skb_push(skb, sizeof(struct mctp_i2c_hdr));
   602		skb_reset_mac_header(skb);
   603		hdr = (void *)skb_mac_header(skb);
   604		mhdr = mctp_hdr(skb);
   605		hdr->dest_slave = (lldst << 1) & 0xff;
   606		hdr->command = MCTP_I2C_COMMANDCODE;
   607		hdr->byte_count = len + 1;
   608		hdr->source_slave = ((llsrc << 1) & 0xff) | 0x01;
   609		mhdr->ver = 0x01;
   610	
   611		return sizeof(struct mctp_i2c_hdr);
   612	}
   613	

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