Re: [PATCH 3/3] kbuild: propagate CONFIG_WERROR to resolve_btfids

[Jiri Olsa]

On Mon, Nov 25, 2024 at 09:20:37AM +0100, Thomas Weißschuh wrote:
> On 2024-11-24 15:38:40-0800, Alexei Starovoitov wrote:
> > On Sat, Nov 23, 2024 at 5:33 AM Thomas Weißschuh <linux@xxxxxxxxxxxxxx> wrote:
> > >
> > > Use CONFIG_WERROR to also fail on warnings emitted by resolve_btfids.
> > > Allow the CI bots to prevent the introduction of new warnings.
> > >
> > > Signed-off-by: Thomas Weißschuh <linux@xxxxxxxxxxxxxx>
> > > ---
> > >  scripts/link-vmlinux.sh | 6 +++++-
> > >  1 file changed, 5 insertions(+), 1 deletion(-)
> > >
> > > diff --git a/scripts/link-vmlinux.sh b/scripts/link-vmlinux.sh
> > > index a9b3f34a78d2cd4514e73a728f1a784eee891768..61f1f670291351a276221153146d66001eca556c 100755
> > > --- a/scripts/link-vmlinux.sh
> > > +++ b/scripts/link-vmlinux.sh
> > > @@ -274,7 +274,11 @@ vmlinux_link vmlinux
> > >  # fill in BTF IDs
> > >  if is_enabled CONFIG_DEBUG_INFO_BTF; then
> > >         info BTFIDS vmlinux
> > > -       ${RESOLVE_BTFIDS} vmlinux
> > > +       RESOLVE_BTFIDS_ARGS=""
> > > +       if is_enabled CONFIG_WERROR; then
> > > +               RESOLVE_BTFIDS_ARGS=" --fatal-warnings "
> > > +       fi
> > > +       ${RESOLVE_BTFIDS} ${RESOLVE_BTFIDS_ARGS} vmlinux
> > 
> > I'm not convinced we need to fail the build when functions are renamed.
> > These warns are eventually found and fixed.
> 
> The same could be said for most other build warnings.
> CONFIG_WERROR is a well-known opt-in switch for exactly this behavior.
> 
> Fixing these warnings before they hit mainline has various
> advantages. The author introducing the warning knows about the full
> impact of their change, discussions can be had when everybody still
> has the topic fresh on their mind and other unrelated people don't get
> confused, like me or [0].
> 
> The "eventually fixed" part seems to have been me the last two times :-)
> 
> Given the fairly simple implementation, in my opinion this is worth doing.
> 
> Please note that I have two fairly trivial changes for a v2 and would
> also like to get some feedback from Masahiro, especially for patch 1.

ok, I think it's fine to fail for CONFIG_WERROR option, for patchset:

Acked-by: Jiri Olsa <jolsa@xxxxxxxxxx>

thanks,
jirka

> 
> 
> Thomas
> 
> [0] https://lore.kernel.org/lkml/20241113093703.9936-1-laura.nao@xxxxxxxxxxxxx/