New warning in linus/master

[Ricardo Ribalda]

Hi Thomas

Thanks for the prompt reply

On Wed, 22 Apr 2026 at 13:57, Thomas Weißschuh
<thomas.weissschuh at linutronix.de> wrote:
>
> Hi Ricardo,
>
> On Wed, Apr 22, 2026 at 11:51:45AM +0800, Ricardo Ribalda wrote:
> > Media-CI has found a couple of new warnings in the latest kernel
> > version for aarch64 and powerpc. They get fixed with this patch and
> > before moving I wanted to know if this was under your radar.
>
> Thanks for the report. I was not aware of these so far.
>
> > diff --git a/arch/arm64/kernel/vdso/Makefile b/arch/arm64/kernel/vdso/Makefile
> > index 7dec05dd33b7..65914842fae0 100644
> > --- a/arch/arm64/kernel/vdso/Makefile
> > +++ b/arch/arm64/kernel/vdso/Makefile
> > @@ -50,7 +50,7 @@ CFLAGS_vgettimeofday.o = $(CC_FLAGS_ADD_VDSO)
> >  CFLAGS_vgetrandom.o = $(CC_FLAGS_ADD_VDSO)
> >
> >  ifneq ($(c-gettimeofday-y),)
> > -  CFLAGS_vgettimeofday.o += -include $(c-gettimeofday-y)
> > +  CFLAGS_vgettimeofday.o += -include $(c-gettimeofday-y)
> > -Wno-maybe-uninitialized
> >  endif
>
> (...)
>
> I'd like to know exactly what is going on before suppressing the warning.
> It is a non-standard warning, only enabled by *some* of the vDSO builds
> for some reason.
>
> > https://gitlab.freedesktop.org/linux-media/users/ribalda/-/pipelines/1649144/test_report?job_name=cross-gcc
>
> While I was able to download a configuration from this job and also use the
> same container image, I can not reproduce the issue. Is the configuration the
> full one or only the template?
>
> Could you provide full reproduction steps?

You can try repro with:

work/linux $ podman run -v .:/workdir/ --rm -it
registry.freedesktop.org/linux-media/media-ci/build:latest
$ cd /workdir
$ CROSS_COMPILE=aarch64-linux-gnu- ARCH=arm64 make allyesconfig
$ CROSS_COMPILE=aarch64-linux-gnu- ARCH=arm64 make
arch/arm64/kernel/vdso/vgettimeofday.o

The gcc version discrepancy is because I the error was due to old gcc
version and I was playing around with that... but it fails in both
gcc14 and gcc15

You can try with debian testing with
work/linux$ podman run -v .:/workdir/ --rm -it debian:testing
$ apt-get update
$ apt-get install gcc-aarch64-linux-gnu build-essential flex bison libssl-dev bc
$ cd /workdir
$ CROSS_COMPILE=aarch64-linux-gnu- ARCH=arm64 make allyesconfig
$ CROSS_COMPILE=aarch64-linux-gnu- ARCH=arm64 make
arch/arm64/kernel/vdso/vgettimeofday.o

Regards!

>
> > CONFIG_CC_VERSION_TEXT="aarch64-linux-gnu-gcc (Debian 15.2.0-16) 15.2.0"
>
> The linked test log shows GCC 14.2, not 15.2.
> Not that I could reproduce it with either one...
>
> >   SYNC    include/config/auto.conf
> >   CC      arch/arm64/kernel/vdso/vgettimeofday.o
> > In file included from <command-line>:
> > In function ‘vdso_set_timespec’,
> >     inlined from ‘do_aux’ at /workdir/lib/vdso/gettimeofday.c:266:2,
> >     inlined from ‘__cvdso_clock_gettime_common’ at
> > /workdir/lib/vdso/gettimeofday.c:293:10,
> >     inlined from ‘__cvdso_clock_gettime_data.constprop’ at
> > /workdir/lib/vdso/gettimeofday.c:306:7:
> > /workdir/lib/vdso/gettimeofday.c:104:26: warning: ‘sec’ may be used
> > uninitialized [-Wmaybe-uninitialized]
> >   104 |         ts->tv_sec = sec + __iter_div_u64_rem(ns, NSEC_PER_SEC, &ns);
> >       |                      ~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> > /workdir/lib/vdso/gettimeofday.c: In function
> > ‘__cvdso_clock_gettime_data.constprop’:
> > /workdir/lib/vdso/gettimeofday.c:242:13: note: ‘sec’ was declared here
> >   242 |         u64 sec, ns;
> >       |             ^~~
>
> The same pattern is used in some other do_ handlers, which do not generate this
> warning. I also can't immediately see what is wrong.
>
> (...)
>
>
> Thomas



-- 
Ricardo Ribalda