On 20 July 2017 at 20:29, Mark Cave-Ayland <mark.cave-ayl...@ilande.co.uk> wrote: > On 19/07/17 18:09, Mark Cave-Ayland wrote: > >> Hi all, >> >> I see the following build failure here on git master with gcc 4.7.2: >> >> cc -I/home/build/src/qemu/git/qemu/block -Iblock >> -I/home/build/src/qemu/git/qemu/tcg >> -I/home/build/src/qemu/git/qemu/tcg/i386 >> -I/home/build/src/qemu/git/qemu/linux-headers >> -I/home/build/src/qemu/git/qemu/linux-headers -I. >> -I/home/build/src/qemu/git/qemu >> -I/home/build/src/qemu/git/qemu/accel/tcg >> -I/home/build/src/qemu/git/qemu/include -I/usr/include/pixman-1 >> -I/home/build/src/qemu/git/qemu/dtc/libfdt -Werror -pthread >> -I/usr/include/glib-2.0 -I/usr/lib/x86_64-linux-gnu/glib-2.0/include >> -m64 -mcx16 -D_GNU_SOURCE -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE >> -Wstrict-prototypes -Wredundant-decls -Wall -Wundef -Wwrite-strings >> -Wmissing-prototypes -fno-strict-aliasing -fno-common -fwrapv >> -Wendif-labels -Wno-missing-include-dirs -Wempty-body -Wnested-externs >> -Wformat-security -Wformat-y2k -Winit-self -Wignored-qualifiers >> -Wold-style-declaration -Wold-style-definition -Wtype-limits >> -fstack-protector-all -I/usr/include/p11-kit-1 >> -I/usr/include/libpng12 -I/home/build/src/qemu/git/qemu/tests -MMD -MP >> -MT block/vpc.o -MF block/vpc.d -O2 -U_FORTIFY_SOURCE >> -D_FORTIFY_SOURCE=2 -g -c -o block/vpc.o block/vpc.c >> block/vpc.c: In function ‘vpc_co_pwritev’: >> block/vpc.c:652:9: error: ‘ret’ may be used uninitialized in this >> function [-Werror=maybe-uninitialized] >> cc1: all warnings being treated as errors >> make: *** [block/vpc.o] Error 1 >> >> At a quick glance it looks as if this is being caused by commit cfc87e00 >> "block/vpc.c: Handle write failures in get_image_offset()". > > The fix is seemingly quite simple: > > diff --git a/block/vpc.c b/block/vpc.c > index 10e6519..574879b 100644 > --- a/block/vpc.c > +++ b/block/vpc.c > @@ -649,7 +649,7 @@ vpc_co_pwritev(BlockDriverState *bs, uint64_t > offset, uint64_t bytes, > int64_t image_offset; > int64_t n_bytes; > int64_t bytes_done = 0; > - int ret; > + int ret = 0; > VHDFooter *footer = (VHDFooter *) s->footer_buf;
Yeah, I think 4.7.2 isn't smart enough to realize this is a false positive (and that compiler is getting old enough that it's not in the set I usually test with). Do you want to send a proper patch? thanks -- PMM
