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From: David Laight <David.Laight@ACULAB.COM>
To: 'Josh Poimboeuf' <jpoimboe@redhat.com>,
	Masahiro Yamada <masahiroy@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Michal Marek <michal.lkml@markovi.net>,
	"linux-hardening@vger.kernel.org"
	<linux-hardening@vger.kernel.org>,
	"Linux Kbuild mailing list" <linux-kbuild@vger.kernel.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Justin Forbes <jforbes@redhat.com>,
	Ondrej Mosnacek <omosnace@redhat.com>,
	Frank Eigler <fche@redhat.com>, Kees Cook <keescook@chromium.org>
Subject: RE: [PATCH RFC] gcc-plugins: Handle GCC version mismatch for OOT modules
Date: Mon, 8 Mar 2021 09:39:42 +0000	[thread overview]
Message-ID: <bb60fe817f5144929a527d1f5768dd1a@AcuMS.aculab.com> (raw)
In-Reply-To: <20210305191835.4e54dei3dmslbo3a@treble>

> - "External modules must be built with the same GCC version"
> 
>   As has been stated repeatedly, by Linus and others, there's no
>   technical reason behind this claim.  It ignores the realities of how
>   distros release the kernel and compiler independently, with separate
>   cadences.  Minor variances in compiler version are ABI compatible.

Aren't major versions ABI compatible?
Otherwise it is a different architecture.

>   Also, for features which are dependent on compiler version, many of
>   those are now enabled by kbuild.  As I suggested to you previously,
>   kbuild should warn when such features get disabled (which can happen
>   due to a compiler/toolchain change or due to a .config copied from
>   another system).

Anything that is just an optimisation (or pessimisation) really
doesn't matter.
AFAICT most of these options are in the latter category.

One think people might do is download a kernel from kernel.org
and then build an extra module for it.
The compiler they have will be completely different.

	David

-
Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)

  reply	other threads:[~2021-03-08  9:40 UTC|newest]

Thread overview: 57+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-01-25 20:42 [PATCH RFC] gcc-plugins: Handle GCC version mismatch for OOT modules Josh Poimboeuf
2021-01-25 21:16 ` Masahiro Yamada
2021-01-25 21:27   ` Josh Poimboeuf
2021-01-25 21:44     ` Masahiro Yamada
2021-01-25 22:07       ` Josh Poimboeuf
2021-01-26  8:13         ` Greg KH
2021-01-26 12:44           ` Justin Forbes
2021-01-26 13:51             ` Greg KH
2021-01-26 14:51               ` Josh Poimboeuf
2021-01-26 15:00                 ` Greg KH
2021-01-26 15:15                 ` Peter Zijlstra
2021-01-26 15:46                   ` Josh Poimboeuf
2021-01-26 16:05                     ` Peter Zijlstra
2021-01-26 16:15                       ` Justin Forbes
2021-01-26 16:19                         ` Josh Poimboeuf
2021-01-26 17:06                           ` Greg KH
2021-01-26 17:47                             ` Justin Forbes
2021-01-26 16:22                       ` David Laight
2021-01-27 18:03             ` Christoph Hellwig
2021-01-26  8:12     ` Greg KH
2021-01-25 22:03 ` Kees Cook
2021-01-25 22:19   ` Josh Poimboeuf
2021-01-26 17:56     ` Kees Cook
2021-01-26 18:43       ` Josh Poimboeuf
2021-01-26 22:59         ` Kees Cook
2021-01-26 23:32           ` Josh Poimboeuf
2021-01-26  1:53   ` Masahiro Yamada
2021-01-26 12:16     ` David Laight
2021-01-27 18:02 ` Christoph Hellwig
2021-01-27 18:38   ` Josh Poimboeuf
2021-01-27 18:43     ` Christoph Hellwig
2021-01-27 18:51       ` Josh Poimboeuf
2021-01-27 22:09         ` David Laight
2021-01-28 14:29         ` Christoph Hellwig
2021-01-28 15:45           ` Josh Poimboeuf
2021-03-02 23:26 ` Josh Poimboeuf
2021-03-03 18:49   ` Masahiro Yamada
2021-03-03 19:15     ` Josh Poimboeuf
2021-03-03 19:25       ` Linus Torvalds
2021-03-03 19:38         ` Josh Poimboeuf
2021-03-03 19:57           ` Linus Torvalds
2021-03-03 20:24             ` Josh Poimboeuf
2021-03-03 20:31               ` Josh Poimboeuf
2021-03-03 20:56               ` Linus Torvalds
2021-03-03 21:45                 ` Josh Poimboeuf
2021-03-04 12:27                   ` Masahiro Yamada
2021-03-04 15:08                     ` Josh Poimboeuf
2021-03-04 15:35                       ` Masahiro Yamada
2021-03-04 19:12                         ` Linus Torvalds
2021-03-05  2:41                           ` Josh Poimboeuf
2021-03-05  2:49                             ` Linus Torvalds
2021-03-05 16:03                             ` Masahiro Yamada
2021-03-05 19:18                               ` Josh Poimboeuf
2021-03-08  9:39                                 ` David Laight [this message]
2021-03-05 15:31                           ` Masahiro Yamada
2021-03-03 21:52             ` Kees Cook
2021-03-04 12:26       ` Masahiro Yamada

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