Re: [PATCH v4 net-next 05/10] net/ncsi: Ethtool operation to get NCSI channel info

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

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Hi Gavin,

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

url:    https://github.com/0day-ci/linux/commits/Gavin-Shan/net-ncsi-Add-debugging-functionality/20170503-185932
config: alpha-allyesconfig (attached as .config)
compiler: alpha-linux-gnu-gcc (Debian 6.1.1-9) 6.1.1 20160705
reproduce:
        wget https://raw.githubusercontent.com/01org/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # save the attached .config to linux build tree
        make.cross ARCH=alpha 

Note: it may well be a FALSE warning. FWIW you are at least aware of it now.
http://gcc.gnu.org/wiki/Better_Uninitialized_Warnings

All warnings (new ones prefixed by >>):

   In file included from include/linux/string.h:18:0,
                    from include/linux/bitmap.h:8,
                    from include/linux/nodemask.h:94,
                    from include/linux/mmzone.h:16,
                    from include/linux/gfp.h:5,
                    from include/linux/kmod.h:22,
                    from include/linux/module.h:13,
                    from net/ncsi/ncsi-ethtool.c:10:
   net/ncsi/ncsi-ethtool.c: In function 'ncsi_get_channel_info':
>> arch/alpha/include/asm/string.h:21:16: warning: 'dest' may be used uninitialized in this function [-Wmaybe-uninitialized]
    #define memcpy __builtin_memcpy
                   ^~~~~~~~~~~~~~~~
   net/ncsi/ncsi-ethtool.c:106:9: note: 'dest' was declared here
      void *dest;
            ^~~~
   net/ncsi/ncsi-ethtool.c:105:26: warning: 'd_idx' may be used uninitialized in this function [-Wmaybe-uninitialized]
      int entry_size, s_idx, d_idx;
                             ^~~~~
   net/ncsi/ncsi-ethtool.c:148:18: warning: 'p_valid_bits' may be used uninitialized in this function [-Wmaybe-uninitialized]
       *p_valid_bits |= (1 << d_idx);
       ~~~~~~~~~~~~~~^~~~~~~~~~~~~~~
--
   In file included from include/linux/string.h:18:0,
                    from include/linux/bitmap.h:8,
                    from include/linux/nodemask.h:94,
                    from include/linux/mmzone.h:16,
                    from include/linux/gfp.h:5,
                    from include/linux/kmod.h:22,
                    from include/linux/module.h:13,
                    from net//ncsi/ncsi-ethtool.c:10:
   net//ncsi/ncsi-ethtool.c: In function 'ncsi_get_channel_info':
>> arch/alpha/include/asm/string.h:21:16: warning: 'dest' may be used uninitialized in this function [-Wmaybe-uninitialized]
    #define memcpy __builtin_memcpy
                   ^~~~~~~~~~~~~~~~
   net//ncsi/ncsi-ethtool.c:106:9: note: 'dest' was declared here
      void *dest;
            ^~~~
   net//ncsi/ncsi-ethtool.c:105:26: warning: 'd_idx' may be used uninitialized in this function [-Wmaybe-uninitialized]
      int entry_size, s_idx, d_idx;
                             ^~~~~
   net//ncsi/ncsi-ethtool.c:148:18: warning: 'p_valid_bits' may be used uninitialized in this function [-Wmaybe-uninitialized]
       *p_valid_bits |= (1 << d_idx);
       ~~~~~~~~~~~~~~^~~~~~~~~~~~~~~

vim +/dest +21 arch/alpha/include/asm/string.h

^1da177e include/asm-alpha/string.h      Linus Torvalds    2005-04-16   5  
^1da177e include/asm-alpha/string.h      Linus Torvalds    2005-04-16   6  /*
^1da177e include/asm-alpha/string.h      Linus Torvalds    2005-04-16   7   * GCC of any recent vintage doesn't do stupid things with bcopy.
^1da177e include/asm-alpha/string.h      Linus Torvalds    2005-04-16   8   * EGCS 1.1 knows all about expanding memcpy inline, others don't.
^1da177e include/asm-alpha/string.h      Linus Torvalds    2005-04-16   9   *
^1da177e include/asm-alpha/string.h      Linus Torvalds    2005-04-16  10   * Similarly for a memset with data = 0.
^1da177e include/asm-alpha/string.h      Linus Torvalds    2005-04-16  11   */
^1da177e include/asm-alpha/string.h      Linus Torvalds    2005-04-16  12  
^1da177e include/asm-alpha/string.h      Linus Torvalds    2005-04-16  13  #define __HAVE_ARCH_MEMCPY
^1da177e include/asm-alpha/string.h      Linus Torvalds    2005-04-16  14  extern void * memcpy(void *, const void *, size_t);
^1da177e include/asm-alpha/string.h      Linus Torvalds    2005-04-16  15  #define __HAVE_ARCH_MEMMOVE
^1da177e include/asm-alpha/string.h      Linus Torvalds    2005-04-16  16  extern void * memmove(void *, const void *, size_t);
^1da177e include/asm-alpha/string.h      Linus Torvalds    2005-04-16  17  
^1da177e include/asm-alpha/string.h      Linus Torvalds    2005-04-16  18  /* For backward compatibility with modules.  Unused otherwise.  */
^1da177e include/asm-alpha/string.h      Linus Torvalds    2005-04-16  19  extern void * __memcpy(void *, const void *, size_t);
^1da177e include/asm-alpha/string.h      Linus Torvalds    2005-04-16  20  
^1da177e include/asm-alpha/string.h      Linus Torvalds    2005-04-16 @21  #define memcpy __builtin_memcpy
^1da177e include/asm-alpha/string.h      Linus Torvalds    2005-04-16  22  
^1da177e include/asm-alpha/string.h      Linus Torvalds    2005-04-16  23  #define __HAVE_ARCH_MEMSET
^1da177e include/asm-alpha/string.h      Linus Torvalds    2005-04-16  24  extern void * __constant_c_memset(void *, unsigned long, size_t);
a47e5bb5 arch/alpha/include/asm/string.h Richard Henderson 2013-07-11  25  extern void * ___memset(void *, int, size_t);
^1da177e include/asm-alpha/string.h      Linus Torvalds    2005-04-16  26  extern void * __memset(void *, int, size_t);
^1da177e include/asm-alpha/string.h      Linus Torvalds    2005-04-16  27  extern void * memset(void *, int, size_t);
^1da177e include/asm-alpha/string.h      Linus Torvalds    2005-04-16  28  
a47e5bb5 arch/alpha/include/asm/string.h Richard Henderson 2013-07-11  29  /* For gcc 3.x, we cannot have the inline function named "memset" because

:::::: The code at line 21 was first introduced by commit
:::::: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 Linux-2.6.12-rc2

:::::: TO: Linus Torvalds <torvalds@ppc970.osdl.org>
:::::: CC: Linus Torvalds <torvalds@ppc970.osdl.org>

---
0-DAY kernel test infrastructure                Open Source Technology Center
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