Re: [PATCH-for-7.0 v2] block-qdict: Fix -Werror=maybe-uninitialized build failure

[Philippe Mathieu-Daudé]

On Wed, Mar 16, 2022 at 3:52 PM Markus Armbruster <armbru@redhat.com> wrote:
>
> Murilo Opsfelder Araújo <muriloo@linux.ibm.com> writes:
>
> > Hi, Philippe.
> >
> > On Monday, March 14, 2022 10:47:11 AM -03 Philippe Mathieu-Daudé wrote:
> >> On 11/3/22 23:16, Murilo Opsfelder Araujo wrote:
> >> > Building QEMU on Fedora 37 (Rawhide Prerelease) ppc64le failed with the
> >> > following error:
> >> >
> >> >      $ ../configure --prefix=/usr/local/qemu-disabletcg 
> >> > --target-list=ppc-softmmu,ppc64-softmmu --disable-tcg 
> >> > --disable-linux-user
> >> >      ...
> >> >      $ make -j$(nproc)
> >> >      ...
> >> >      FAILED: libqemuutil.a.p/qobject_block-qdict.c.o
> >>
> >> This part >>>
> >>
> >> >      cc -m64 -mlittle-endian -Ilibqemuutil.a.p -I. -I.. 
> >> > -Isubprojects/libvhost-user -I../subprojects/libvhost-user -Iqapi 
> >> > -Itrace -Iui -Iui/shader -I/usr/include/glib-2.0 
> >> > -I/usr/lib64/glib-2.0/include -I/usr/include/sysprof-4 -I/usr/include/lib
> >> >      mount -I/usr/include/blkid -I/usr/include/gio-unix-2.0 
> >> > -I/usr/include/p11-kit-1 -I/usr/include/pixman-1 
> >> > -fdiagnostics-color=auto -Wall -Winvalid-pch -Werror -std=gnu11 -O2 -g 
> >> > -isystem /root/qemu/linux-headers -isystem linux-headers -iquote
> >> >       . -iquote /root/qemu -iquote /root/qemu/include -iquote 
> >> > /root/qemu/disas/libvixl -pthread -U_FORTIFY_SOURCE -D_FORTIFY_SOURCE=2 
> >> > -D_GNU_SOURCE -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE 
> >> > -Wstrict-prototypes -Wredundant-decls -Wundef -Wwrite
> >> >      -strings -Wmissing-prototypes -fno-strict-aliasing -fno-common 
> >> > -fwrapv -Wold-style-declaration -Wold-style-definition -Wtype-limits 
> >> > -Wformat-security -Wformat-y2k -Winit-self -Wignored-qualifiers 
> >> > -Wempty-body -Wnested-externs -Wendif-label
> >> >      s -Wexpansion-to-defined -Wimplicit-fallthrough=2 
> >> > -Wno-missing-include-dirs -Wno-shift-negative-value -Wno-psabi 
> >> > -fstack-protector-strong -fPIE -MD -MQ 
> >> > libqemuutil.a.p/qobject_block-qdict.c.o -MF 
> >> > libqemuutil.a.p/qobject_block-qdict.c.o.d -
> >> >      o libqemuutil.a.p/qobject_block-qdict.c.o -c 
> >> > ../qobject/block-qdict.c
> >>
> >> <<< is noise (doesn't provide any value) and could be stripped.
> >
> > Is this something the committer/maintainer could edit when applying the 
> > commit
> > or do you need I resend the v3?
> >
> > Cheers!
>
> I'll take care of it unless Kevin or Hanna beat me to the punch.

Thanks!

Same error on latest Debian:

include/qapi/qmp/qobject.h: In function 'qdict_array_split':
include/qapi/qmp/qobject.h:49:17: error: 'subqdict' may be used
uninitialized [-Werror=maybe-uninitialized]
   49 |     typeof(obj) _obj = (obj);                                   \
      |                 ^~~~
../qobject/block-qdict.c:227:16: note: 'subqdict' declared here
  227 |         QDict *subqdict;
      |                ^~~~~~~~
cc1: all warnings being treated as errors
FAILED: libqemuutil.a.p/qobject_block-qdict.c.o

Tested-by: Philippe Mathieu-Daudé <f4bug@amsat.org>