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From: Uros Bizjak <ubizjak@gmail.com>
Date: Tue, 26 Mar 2024 08:02:33 +0100
Message-ID: <CAFULd4biN8FPRtU54Q0QywfBFvvWV-s1M3kWF9YOmozyAX9+ZQ@mail.gmail.com>
Subject: Re: [PATCH v4 00/16] x86-64: Stack protector and percpu improvements
To: Arnd Bergmann <arnd@arndb.de>
Cc: Takashi Iwai <tiwai@suse.de>, Linus Torvalds <torvalds@linux-foundation.org>, 
	Brian Gerst <brgerst@gmail.com>, linux-kernel@vger.kernel.org, x86@kernel.org, 
	Ingo Molnar <mingo@kernel.org>, Thomas Gleixner <tglx@linutronix.de>, Borislav Petkov <bp@alien8.de>, 
	"H. Peter Anvin" <hpa@zytor.com>, mwilck@suse.com, Vlastimil Babka <vbabka@suse.cz>, denis.kirjanov@suse.com, 
	nmorey@suse.com
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On Mon, Mar 25, 2024 at 7:08=E2=80=AFPM Arnd Bergmann <arnd@arndb.de> wrote=
:
>
> On Mon, Mar 25, 2024, at 16:26, Takashi Iwai wrote:
> > On Mon, 25 Mar 2024 15:51:30 +0100, Arnd Bergmann wrote:
> >
> >> Not sure if they plan to update the kernel release beyond that,
> >> or how inconvenient it would be for them to require
> >> using the other compiler for future updates, so I've added
> >> the developers that last touched the OpenSUSE kernel RPM
> >> package to Cc here.
> >
> > SLE15-SP6 kernel (based on 6.4.x) is still built with gcc7, currently
> > gcc 7.5, indeed.  openSUSE Leap shares the very same kernel, so it's
> > with gcc 7.5, too.  Even though gcc-13 is provided as additional
> > compiler package, it's not used for the kernel package build.
>
> Ok, so for SP6 there won't be a problem because it won't
> update the kernel.
>
> > AFAIK, it's not decided yet about SP7 kernel.  But since we take a
> > conservative approach for SLE, I guess SLE15-SP7 will be likely
> > sticking with the old gcc, unless forced to change by some reason.
>
> From https://www.suse.com/support/kb/doc/?id=3D000019587, it
> looks like kernel versions are historically only updated for
> even numbered updates (SP2, SP4, SP6), so I guess there is a
> good chance that SP7 won't upgrade either, even if that decision
> is still to be made.
>
> I would assume that if SP7 does get a new kernel, it would
> not be any later than the next LTS kernel (6.12 according
> to phb-crystal-ball), and we could just decide to move to
> gcc-8 only after that is out.

I think that upgrading the compiler to 8.1 after 6.12 LTS is a good plan.

Following that plan also means that the original stack protector
improvement series that includes objtool changes is the way to go
forward. The stack protector specific part can be removed from objtool
after the compiler is upgraded.

Thanks,
Uros.