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Date: Mon, 25 Mar 2024 19:08:20 +0100
From: "Arnd Bergmann" <arnd@arndb.de>
To: "Takashi Iwai" <tiwai@suse.de>
Cc: "Linus Torvalds" <torvalds@linux-foundation.org>,
 "Brian Gerst" <brgerst@gmail.com>, "Uros Bizjak" <ubizjak@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
Subject: Re: [PATCH v4 00/16] x86-64: Stack protector and percpu improvements
Content-Type: text/plain

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=000019587, 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.

> SLE12 is built with the old gcc 4.8, and SLE12-SP5 (based on 4.12) is
> still actively maintained, but only for a few months until October
> 2024.

Right, and it also never updated beyond linux-4.12, which still
supported gcc-4.8. gcc-4.9 only became a requirement in linux-5.9.

> The next generation of SLE is built with the latest gcc (gcc-13 for
> now).  So SLE16 will be a totally different story.
>
> openSUSE Tumbleweed always uses a bleeding edge compiler (gcc-13),
> too.

Thanks for the detailed reply!
 
      Arnd