Re: [PATCH] correct disabling of -Wshift-negative-value

[Nathan Chancellor <nathan@kernel.org>]

On Tue, Apr 15, 2025 at 07:53:12AM +0200, Jan Beulich wrote:
> On 14.04.2025 21:38, Nathan Chancellor wrote:
> > On Mon, Apr 14, 2025 at 04:23:36PM +0200, Jan Beulich wrote:
> >> The warning is supported only from gcc6 onwards, hence its disabling
> >> needs probing that the (positive) option is actually supported.
> >>
> >> Fixes: 1344794a59db ("Kbuild: add -Wno-shift-negative-value where -Wextra is used")
> >> Signed-off-by: Jan Beulich <jbeulich@suse.com>
> > 
> > The patch itself seems fine (I might add "scripts/Makefile.extrawarn: "
> > to the title) but if I understand correctly, this is only to support GCC
> > 5? Would this be necessary if GCC 8.1 becomes the minimum supported
> > version of GCC for building the kernel?
> > 
> > https://lore.kernel.org/20250407094116.1339199-2-arnd@kernel.org/
> > 
> > If people are actively noticing this, perhaps we should send this to
> > Linus's tree for backports then Arnd could revert it in his series?
> 
> Actually, aiui that work was meanwhile merged. Hence the patch here is

I think only x86 has been bumped to a minimum of GCC 8.1 so far, done in
commit a3e8fe814ad1 ("x86/build: Raise the minimum GCC version to 8.1").
That series is still being reviewed/worked on as far as I can tell, so I
think these patches would still be needed for other architectures.

> indeed only applicable to stable trees. No idea how such a situation
> is to be handled. (Apparently the same is true for "correct disabling
> of -Wstringop-overflow": That option was introduced in gcc7.)

Normally, you would just send a patch to the stable maintainers and
mailing list just like this but the commit message would say something
like "<xyz problem> was fixed in mainline in such a way that cannot be
easily backported due to <xyz reason> so do <xyz thing> to resolve said
problem in the stable trees".

Cheers,
Nathan