tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master head: 72714841b705a5b9bccf37ee85a62352bee3a3ef commit: 71458cfc782eafe4b27656e078d379a34e472adf kernel: add support for gcc 5 date: 11 months ago config: i386-randconfig-c0-09170850 (attached as .config) reproduce: git checkout 71458cfc782eafe4b27656e078d379a34e472adf # 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:17, from include/linux/dynamic_debug.h:111, from include/linux/printk.h:260, from include/linux/kernel.h:13, from arch/x86/include/asm/percpu.h:44, from arch/x86/include/asm/preempt.h:5, from include/linux/preempt.h:18, from include/linux/uaccess.h:4, from fs/reiserfs/ibalance.c:5: fs/reiserfs/ibalance.c: In function 'balance_internal': >> arch/x86/include/asm/string_32.h:182:25: warning: 'new_insert_key' may be used uninitialized in this function [-Wmaybe-uninitialized] #define memcpy(t, f, n) __builtin_memcpy(t, f, n) ^ fs/reiserfs/ibalance.c:821:19: note: 'new_insert_key' was declared here struct item_head new_insert_key; ^ vim +/new_insert_key +182 arch/x86/include/asm/string_32.h ^1da177e include/asm-i386/string.h Linus Torvalds 2005-04-16 166 } ^1da177e include/asm-i386/string.h Linus Torvalds 2005-04-16 167 ^1da177e include/asm-i386/string.h Linus Torvalds 2005-04-16 168 #define memcpy(t, f, n) \ 78d64fc2 include/asm-x86/string_32.h Joe Perches 2008-05-12 169 (__builtin_constant_p((n)) \ 78d64fc2 include/asm-x86/string_32.h Joe Perches 2008-05-12 170 ? __constant_memcpy3d((t), (f), (n)) \ 78d64fc2 include/asm-x86/string_32.h Joe Perches 2008-05-12 171 : __memcpy3d((t), (f), (n))) ^1da177e include/asm-i386/string.h Linus Torvalds 2005-04-16 172 ^1da177e include/asm-i386/string.h Linus Torvalds 2005-04-16 173 #else ^1da177e include/asm-i386/string.h Linus Torvalds 2005-04-16 174 ^1da177e include/asm-i386/string.h Linus Torvalds 2005-04-16 175 /* ^1da177e include/asm-i386/string.h Linus Torvalds 2005-04-16 176 * No 3D Now! ^1da177e include/asm-i386/string.h Linus Torvalds 2005-04-16 177 */ ^1da177e include/asm-i386/string.h Linus Torvalds 2005-04-16 178 f8561296 arch/x86/include/asm/string_32.h Vegard Nossum 2008-04-04 179 #ifndef CONFIG_KMEMCHECK ff60fab7 arch/x86/include/asm/string_32.h Arjan van de Ven 2009-09-28 180 ff60fab7 arch/x86/include/asm/string_32.h Arjan van de Ven 2009-09-28 181 #if (__GNUC__ >= 4) ff60fab7 arch/x86/include/asm/string_32.h Arjan van de Ven 2009-09-28 @182 #define memcpy(t, f, n) __builtin_memcpy(t, f, n) ff60fab7 arch/x86/include/asm/string_32.h Arjan van de Ven 2009-09-28 183 #else ^1da177e include/asm-i386/string.h Linus Torvalds 2005-04-16 184 #define memcpy(t, f, n) \ 78d64fc2 include/asm-x86/string_32.h Joe Perches 2008-05-12 185 (__builtin_constant_p((n)) \ 78d64fc2 include/asm-x86/string_32.h Joe Perches 2008-05-12 186 ? __constant_memcpy((t), (f), (n)) \ 78d64fc2 include/asm-x86/string_32.h Joe Perches 2008-05-12 187 : __memcpy((t), (f), (n))) ff60fab7 arch/x86/include/asm/string_32.h Arjan van de Ven 2009-09-28 188 #endif f8561296 arch/x86/include/asm/string_32.h Vegard Nossum 2008-04-04 189 #else f8561296 arch/x86/include/asm/string_32.h Vegard Nossum 2008-04-04 190 /* :::::: The code at line 182 was first introduced by commit :::::: ff60fab71bb3b4fdbf8caf57ff3739ffd0887396 x86: Use __builtin_memset and __builtin_memcpy for memset/memcpy :::::: TO: Arjan van de Ven :::::: CC: H. Peter Anvin --- 0-DAY kernel test infrastructure Open Source Technology Center https://lists.01.org/pipermail/kbuild-all Intel Corporation