Re: [v2 PATCH 1/2] scsi:stex.c Support Pegasus 3 product

[kbuild test robot]

Hi,

[auto build test WARNING on scsi/for-next]
[also build test WARNING on v4.7-rc3 next-20160614]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/Charles-Chiou/scsi-stex-c-Support-Pegasus-3-product/20160614-142621
base:   https://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi.git for-next
config: i386-allmodconfig (attached as .config)
compiler: gcc-6 (Debian 6.1.1-1) 6.1.1 20160430
reproduce:
        # save the attached .config to linux build tree
        make ARCH=i386 

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 arch/x86/include/asm/string.h:2:0,
                    from include/linux/string.h:18,
                    from arch/x86/include/asm/page_32.h:34,
                    from arch/x86/include/asm/page.h:13,
                    from arch/x86/include/asm/thread_info.h:11,
                    from include/linux/thread_info.h:54,
                    from arch/x86/include/asm/preempt.h:6,
                    from include/linux/preempt.h:59,
                    from include/linux/spinlock.h:50,
                    from include/linux/mmzone.h:7,
                    from include/linux/gfp.h:5,
                    from include/linux/slab.h:14,
                    from drivers/scsi/stex.c:20:
   drivers/scsi/stex.c: In function 'stex_handshake':
>> arch/x86/include/asm/string_32.h:325:29: warning: 'scratch' may be used uninitialized in this function [-Wmaybe-uninitialized]
    #define memset(s, c, count) __builtin_memset(s, c, count)
                                ^~~~~~~~~~~~~~~~
   drivers/scsi/stex.c:1111:10: note: 'scratch' was declared here
     __le32 *scratch;
             ^~~~~~~

vim +/scratch +325 arch/x86/include/asm/string_32.h

^1da177e include/asm-i386/string.h        Linus Torvalds   2005-04-16  309  
^1da177e include/asm-i386/string.h        Linus Torvalds   2005-04-16  310  #undef COMMON
^1da177e include/asm-i386/string.h        Linus Torvalds   2005-04-16  311  }
^1da177e include/asm-i386/string.h        Linus Torvalds   2005-04-16  312  
^1da177e include/asm-i386/string.h        Linus Torvalds   2005-04-16  313  #define __constant_c_x_memset(s, c, count)			\
78d64fc2 include/asm-x86/string_32.h      Joe Perches      2008-05-12  314  	(__builtin_constant_p(count)				\
78d64fc2 include/asm-x86/string_32.h      Joe Perches      2008-05-12  315  	 ? __constant_c_and_count_memset((s), (c), (count))	\
78d64fc2 include/asm-x86/string_32.h      Joe Perches      2008-05-12  316  	 : __constant_c_memset((s), (c), (count)))
^1da177e include/asm-i386/string.h        Linus Torvalds   2005-04-16  317  
^1da177e include/asm-i386/string.h        Linus Torvalds   2005-04-16  318  #define __memset(s, c, count)				\
78d64fc2 include/asm-x86/string_32.h      Joe Perches      2008-05-12  319  	(__builtin_constant_p(count)			\
78d64fc2 include/asm-x86/string_32.h      Joe Perches      2008-05-12  320  	 ? __constant_count_memset((s), (c), (count))	\
78d64fc2 include/asm-x86/string_32.h      Joe Perches      2008-05-12  321  	 : __memset_generic((s), (c), (count)))
^1da177e include/asm-i386/string.h        Linus Torvalds   2005-04-16  322  
^1da177e include/asm-i386/string.h        Linus Torvalds   2005-04-16  323  #define __HAVE_ARCH_MEMSET
ff60fab7 arch/x86/include/asm/string_32.h Arjan van de Ven 2009-09-28  324  #if (__GNUC__ >= 4)
ff60fab7 arch/x86/include/asm/string_32.h Arjan van de Ven 2009-09-28 @325  #define memset(s, c, count) __builtin_memset(s, c, count)
ff60fab7 arch/x86/include/asm/string_32.h Arjan van de Ven 2009-09-28  326  #else
^1da177e include/asm-i386/string.h        Linus Torvalds   2005-04-16  327  #define memset(s, c, count)						\
78d64fc2 include/asm-x86/string_32.h      Joe Perches      2008-05-12  328  	(__builtin_constant_p(c)					\
78d64fc2 include/asm-x86/string_32.h      Joe Perches      2008-05-12  329  	 ? __constant_c_x_memset((s), (0x01010101UL * (unsigned char)(c)), \
78d64fc2 include/asm-x86/string_32.h      Joe Perches      2008-05-12  330  				 (count))				\
78d64fc2 include/asm-x86/string_32.h      Joe Perches      2008-05-12  331  	 : __memset((s), (c), (count)))
ff60fab7 arch/x86/include/asm/string_32.h Arjan van de Ven 2009-09-28  332  #endif
^1da177e include/asm-i386/string.h        Linus Torvalds   2005-04-16  333  

:::::: The code at line 325 was first introduced by commit
:::::: ff60fab71bb3b4fdbf8caf57ff3739ffd0887396 x86: Use __builtin_memset and __builtin_memcpy for memset/memcpy

:::::: TO: Arjan van de Ven <arjan@xxxxxxxxxxxxx>
:::::: CC: H. Peter Anvin <hpa@xxxxxxxxx>

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