Re: [PATCH v1] smsc911x: add second read of EEPROM mac when possible corruption seen

kernel test robot <[email protected]>
Newsgroups dev.linux.lists.llvm,dev.linux.lists.oe-kbuild-all,org.kernel.vger.linux-kernel,org.kernel.vger.netdev
Message-ID <[email protected]> 
Hi Colin,

kernel test robot noticed the following build warnings:

[auto build test WARNING on horms-ipvs/master]
[cannot apply to linus/master v7.2-rc7 next-20260807]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Colin-Foster/smsc911x-add-second-read-of-EEPROM-mac-when-possible-corruption-seen/20260810-123819
base:   https://git.kernel.org/pub/scm/linux/kernel/git/horms/ipvs.git master
patch link:    https://lore.kernel.org/r/20250828214452.11683-1-colin.foster%40in-advantage.com
patch subject: [PATCH v1] smsc911x: add second read of EEPROM mac when possible corruption seen
config: hexagon-randconfig-001-20260811 (https://download.01.org/0day-ci/archive/20260811/[email protected]/config)
compiler: clang version 24.0.0git (https://github.com/llvm/llvm-project 12df34b8469b8095359de8c249cb1b2753fadeea)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260811/[email protected]/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 <[email protected]>
| Closes: https://lore.kernel.org/oe-kbuild-all/[email protected]/

All warnings (new ones prefixed by >>):

   In file included from drivers/net/ethernet/smsc/smsc911x.c:25:
   In file included from include/linux/etherdevice.h:20:
   In file included from include/linux/if_ether.h:19:
   In file included from include/linux/skbuff.h:17:
   In file included from include/linux/bvec.h:10:
   In file included from include/linux/highmem.h:12:
   In file included from include/linux/hardirq.h:11:
   In file included from ./arch/hexagon/include/generated/asm/hardirq.h:1:
   In file included from include/asm-generic/hardirq.h:17:
   In file included from include/linux/irq.h:20:
   In file included from include/linux/io.h:13:
   In file included from arch/hexagon/include/asm/io.h:334:
   include/asm-generic/io.h:547:31: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     547 |         val = __raw_readb(PCI_IOBASE + addr);
         |                           ~~~~~~~~~~ ^
   include/asm-generic/io.h:560:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     560 |         val = __le16_to_cpu((__le16 __force)__raw_readw(PCI_IOBASE + addr));
         |                                                         ~~~~~~~~~~ ^
   include/uapi/linux/byteorder/little_endian.h:37:51: note: expanded from macro '__le16_to_cpu'
      37 | #define __le16_to_cpu(x) ((__force __u16)(__le16)(x))
         |                                                   ^
   In file included from drivers/net/ethernet/smsc/smsc911x.c:25:
   In file included from include/linux/etherdevice.h:20:
   In file included from include/linux/if_ether.h:19:
   In file included from include/linux/skbuff.h:17:
   In file included from include/linux/bvec.h:10:
   In file included from include/linux/highmem.h:12:
   In file included from include/linux/hardirq.h:11:
   In file included from ./arch/hexagon/include/generated/asm/hardirq.h:1:
   In file included from include/asm-generic/hardirq.h:17:
   In file included from include/linux/irq.h:20:
   In file included from include/linux/io.h:13:
   In file included from arch/hexagon/include/asm/io.h:334:
   include/asm-generic/io.h:573:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     573 |         val = __le32_to_cpu((__le32 __force)__raw_readl(PCI_IOBASE + addr));
         |                                                         ~~~~~~~~~~ ^
   include/uapi/linux/byteorder/little_endian.h:35:51: note: expanded from macro '__le32_to_cpu'
      35 | #define __le32_to_cpu(x) ((__force __u32)(__le32)(x))
         |                                                   ^
   In file included from drivers/net/ethernet/smsc/smsc911x.c:25:
   In file included from include/linux/etherdevice.h:20:
   In file included from include/linux/if_ether.h:19:
   In file included from include/linux/skbuff.h:17:
   In file included from include/linux/bvec.h:10:
   In file included from include/linux/highmem.h:12:
   In file included from include/linux/hardirq.h:11:
   In file included from ./arch/hexagon/include/generated/asm/hardirq.h:1:
   In file included from include/asm-generic/hardirq.h:17:
   In file included from include/linux/irq.h:20:
   In file included from include/linux/io.h:13:
   In file included from arch/hexagon/include/asm/io.h:334:
   include/asm-generic/io.h:584:33: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     584 |         __raw_writeb(value, PCI_IOBASE + addr);
         |                             ~~~~~~~~~~ ^
   include/asm-generic/io.h:594:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     594 |         __raw_writew((u16 __force)cpu_to_le16(value), PCI_IOBASE + addr);
         |                                                       ~~~~~~~~~~ ^
   include/asm-generic/io.h:604:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     604 |         __raw_writel((u32 __force)cpu_to_le32(value), PCI_IOBASE + addr);
         |                                                       ~~~~~~~~~~ ^
>> drivers/net/ethernet/smsc/smsc911x.c:2179:5: warning: mixing declarations and code is incompatible with standards before C99 [-Wdeclaration-after-statement]
    2179 |         u8 addr[ETH_ALEN];
         |            ^
   7 warnings generated.


vim +2179 drivers/net/ethernet/smsc/smsc911x.c

631b7568c7d8f02 drivers/net/smsc911x.c               Steve Glendinning 2008-12-25  2160  
31f4574774e98aa drivers/net/smsc911x.c               Steve Glendinning 2009-01-27  2161  /* copies the current mac address from hardware to dev->dev_addr */
8489ec1f9700649 drivers/net/ethernet/smsc/smsc911x.c Bill Pemberton    2012-12-03  2162  static void smsc911x_read_mac_address(struct net_device *dev)
31f4574774e98aa drivers/net/smsc911x.c               Steve Glendinning 2009-01-27  2163  {
31f4574774e98aa drivers/net/smsc911x.c               Steve Glendinning 2009-01-27  2164  	struct smsc911x_data *pdata = netdev_priv(dev);
8b1e595e2e78004 drivers/net/ethernet/smsc/smsc911x.c Colin Foster      2025-08-28  2165  	u32 mac_high16, mac_low32;
8b1e595e2e78004 drivers/net/ethernet/smsc/smsc911x.c Colin Foster      2025-08-28  2166  
8b1e595e2e78004 drivers/net/ethernet/smsc/smsc911x.c Colin Foster      2025-08-28  2167  	mac_high16 = smsc911x_mac_read(pdata, ADDRH);
8b1e595e2e78004 drivers/net/ethernet/smsc/smsc911x.c Colin Foster      2025-08-28  2168  	mac_low32 = smsc911x_mac_read(pdata, ADDRL);
8b1e595e2e78004 drivers/net/ethernet/smsc/smsc911x.c Colin Foster      2025-08-28  2169  
8b1e595e2e78004 drivers/net/ethernet/smsc/smsc911x.c Colin Foster      2025-08-28  2170  	/*
8b1e595e2e78004 drivers/net/ethernet/smsc/smsc911x.c Colin Foster      2025-08-28  2171  	 * The first mac_read always returns 0. Re-read it to get the
8b1e595e2e78004 drivers/net/ethernet/smsc/smsc911x.c Colin Foster      2025-08-28  2172  	 * full MAC
8b1e595e2e78004 drivers/net/ethernet/smsc/smsc911x.c Colin Foster      2025-08-28  2173  	 */
8b1e595e2e78004 drivers/net/ethernet/smsc/smsc911x.c Colin Foster      2025-08-28  2174  	if (mac_high16 == 0) {
8b1e595e2e78004 drivers/net/ethernet/smsc/smsc911x.c Colin Foster      2025-08-28  2175  		SMSC_TRACE(pdata, probe, "Re-read MAC ADDRH\n");
8b1e595e2e78004 drivers/net/ethernet/smsc/smsc911x.c Colin Foster      2025-08-28  2176  		mac_high16 = smsc911x_mac_read(pdata, ADDRH);
8b1e595e2e78004 drivers/net/ethernet/smsc/smsc911x.c Colin Foster      2025-08-28  2177  	}
8b1e595e2e78004 drivers/net/ethernet/smsc/smsc911x.c Colin Foster      2025-08-28  2178  
f15fef4c0675d41 drivers/net/ethernet/smsc/smsc911x.c Jakub Kicinski    2021-10-18 @2179  	u8 addr[ETH_ALEN];
f15fef4c0675d41 drivers/net/ethernet/smsc/smsc911x.c Jakub Kicinski    2021-10-18  2180  
f15fef4c0675d41 drivers/net/ethernet/smsc/smsc911x.c Jakub Kicinski    2021-10-18  2181  	addr[0] = (u8)(mac_low32);
f15fef4c0675d41 drivers/net/ethernet/smsc/smsc911x.c Jakub Kicinski    2021-10-18  2182  	addr[1] = (u8)(mac_low32 >> 8);
f15fef4c0675d41 drivers/net/ethernet/smsc/smsc911x.c Jakub Kicinski    2021-10-18  2183  	addr[2] = (u8)(mac_low32 >> 16);
f15fef4c0675d41 drivers/net/ethernet/smsc/smsc911x.c Jakub Kicinski    2021-10-18  2184  	addr[3] = (u8)(mac_low32 >> 24);
f15fef4c0675d41 drivers/net/ethernet/smsc/smsc911x.c Jakub Kicinski    2021-10-18  2185  	addr[4] = (u8)(mac_high16);
f15fef4c0675d41 drivers/net/ethernet/smsc/smsc911x.c Jakub Kicinski    2021-10-18  2186  	addr[5] = (u8)(mac_high16 >> 8);
f15fef4c0675d41 drivers/net/ethernet/smsc/smsc911x.c Jakub Kicinski    2021-10-18  2187  	eth_hw_addr_set(dev, addr);
31f4574774e98aa drivers/net/smsc911x.c               Steve Glendinning 2009-01-27  2188  }
31f4574774e98aa drivers/net/smsc911x.c               Steve Glendinning 2009-01-27  2189  

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