Re: [RFC] minimum gcc version for kernel: raise to gcc-4.3 or 4.6?

From: Suzuki K Poulose
Date: Tue Apr 25 2017 - 05:24:15 EST


On 16/04/17 20:52, Kees Cook wrote:
Was there a conclusion to this discussion? I didn't see anything
definitive in the thread...

Notes below...

On Fri, Dec 16, 2016 at 3:14 AM, Arnd Bergmann <arnd@xxxxxxxx> wrote:
[Fixed linux-arm-kernel mailing list address, sorry for the duplicate,
I'm not reposting all the ugly patches though, unless someone really
wants them, https://lkml.org/lkml/2016/12/16/174 has a copy]

On Friday, December 16, 2016 11:56:21 AM CET Arnd Bergmann wrote:
I had some fun doing build testing with older gcc versions, building
every release from 4.0 through 7.0 and running that on my randconfig
setup to see what comes out.

First of all, gcc-4.9 and higher is basically warning-free everywhere,
although gcc-7 introduces some interesting new warnings (I have started
doing patches for those as well). gcc-4.8 is probably good, too, and
gcc-4.6 and 4.7 at least don't produce build failures in general, though
the level of false-positive warnings increases (we could decide to turn
those off for older compilers for build test purposes).

In gcc-4.5 and below, dead code elimination is not as good as later,
causing a couple of link errors, and some of them have no good workaround
(see patch 1). It would be nice to declare that version too old, but
several older distros that are still in wide use ship with compilers
earlier than 4.6:

RHEL6: gcc-4.4

This appears to have support until July 31, 2018. (Though it's using a
2.6 kernel.)

Debian 6: gcc-4.4

This went fully unsupported on Feb 29, 2016.

Ubuntu 10.04: gcc-4.4

This went fully unsupported on Apr 30, 2015.

SLES11: gcc-4.3

General support ends Mar 31 2019, fully unsupported 31 Mar 2022. (And
like RHEL6 is using a 2.6 kernel.)

fyi, SLES11 upgraded to kernel 3.0, in SP2.

https://www.novell.com/support/kb/doc.php?id=3594951

Cheers
Suzuki