Hi Stanislaw, [auto build test WARNING on net-next/master] [also build test WARNING on v4.10-rc6] [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/Stanislaw-Gruszka/ethtool-do-not-vzalloc-0-on-registers-dump/20170202-194352 config: i386-randconfig-x001-201705 (attached as .config) compiler: gcc-6 (Debian 6.2.0-3) 6.2.0 20160901 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 include/linux/uaccess.h:5:0, from include/net/checksum.h:25, from include/linux/skbuff.h:31, from include/linux/if_ether.h:23, from include/uapi/linux/ethtool.h:18, from include/linux/ethtool.h:17, from net/core/ethtool.c:18: net/core/ethtool.c: In function 'dev_ethtool': >> arch/x86/include/asm/uaccess.h:722:5: warning: 'regbuf' may be used >> uninitialized in this function [-Wmaybe-uninitialized] n = _copy_to_user(to, from, n); ~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~ net/core/ethtool.c:1395:8: note: 'regbuf' was declared here void *regbuf; ^~~~~~ vim +/regbuf +722 arch/x86/include/asm/uaccess.h 0d025d27 Josh Poimboeuf 2016-08-30 706 __bad_copy_user(); 3df7b41a Jan Beulich 2013-10-21 707 3df7b41a Jan Beulich 2013-10-21 708 return n; 3df7b41a Jan Beulich 2013-10-21 709 } 3df7b41a Jan Beulich 2013-10-21 710 e6971009 Kees Cook 2016-09-06 711 static __always_inline unsigned long __must_check 7a3d9b0f Jan Beulich 2013-10-21 712 copy_to_user(void __user *to, const void *from, unsigned long n) 7a3d9b0f Jan Beulich 2013-10-21 713 { 7a3d9b0f Jan Beulich 2013-10-21 714 int sz = __compiletime_object_size(from); 7a3d9b0f Jan Beulich 2013-10-21 715 1771c6e1 Andrey Ryabinin 2016-05-20 716 kasan_check_read(from, n); 1771c6e1 Andrey Ryabinin 2016-05-20 717 7a3d9b0f Jan Beulich 2013-10-21 718 might_fault(); 7a3d9b0f Jan Beulich 2013-10-21 719 5b710f34 Kees Cook 2016-06-23 720 if (likely(sz < 0 || sz >= n)) { 5b710f34 Kees Cook 2016-06-23 721 check_object_size(from, n, true); 7a3d9b0f Jan Beulich 2013-10-21 @722 n = _copy_to_user(to, from, n); 0d025d27 Josh Poimboeuf 2016-08-30 723 } else if (!__builtin_constant_p(n)) 0d025d27 Josh Poimboeuf 2016-08-30 724 copy_user_overflow(sz, n); 7a3d9b0f Jan Beulich 2013-10-21 725 else 0d025d27 Josh Poimboeuf 2016-08-30 726 __bad_copy_user(); 7a3d9b0f Jan Beulich 2013-10-21 727 7a3d9b0f Jan Beulich 2013-10-21 728 return n; 7a3d9b0f Jan Beulich 2013-10-21 729 } 7a3d9b0f Jan Beulich 2013-10-21 730 :::::: The code at line 722 was first introduced by commit :::::: 7a3d9b0f3abbea957b829cdfff8169872c575642 x86: Unify copy_to_user() and add size checking to it :::::: TO: Jan Beulich <[email protected]> :::::: CC: Ingo Molnar <[email protected]> --- 0-DAY kernel test infrastructure Open Source Technology Center https://lists.01.org/pipermail/kbuild-all Intel Corporation
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