From: Florian Weimer <fweimer@redhat.com>
To: Pavel Machek <pavel@ucw.cz>
Cc: Randy Dunlap <rdunlap@infradead.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Marco Elver <elver@google.com>,
Nick Desaulniers <ndesaulniers@google.com>,
llvm@lists.linux.dev,
LSM List <linux-security-module@vger.kernel.org>,
linux-toolchains@vger.kernel.org, Arnd Bergmann <arnd@arndb.de>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Guenter Roeck <linux@roeck-us.net>,
Kees Cook <keescook@chromium.org>,
Mark Brown <broonie@kernel.org>,
Masahiro Yamada <masahiroy@kernel.org>,
Nathan Chancellor <nathan@kernel.org>,
Michal Marek <michal.lkml@markovi.net>,
Andrew Morton <akpm@linux-foundation.org>,
Vipin Sharma <vipinsh@google.com>,
Chris Down <chris@chrisdown.name>,
Rasmus Villemoes <linux@rasmusvillemoes.dk>,
Daniel Borkmann <daniel@iogearbox.net>,
Vlastimil Babka <vbabka@suse.cz>,
Linux Kbuild mailing list <linux-kbuild@vger.kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] Revert "Enable '-Werror' by default for all kernel builds"
Date: Mon, 13 Sep 2021 11:50:31 +0200 [thread overview]
Message-ID: <87a6kgerdk.fsf@oldenburg.str.redhat.com> (raw)
In-Reply-To: <20210913093256.GA12225@amd> (Pavel Machek's message of "Mon, 13 Sep 2021 11:32:56 +0200")
* Pavel Machek:
> Do we really want developers treat warnings as errors? When the code
> is okay but some random version of gcc dislikes it...
There are some warnings-as-errors which are quite reasonable, like
-Werror=implicit-function-declaration (which we can't make the compiler
default without cleaning up userspace first) and perhaps
-Werror=implicit-int. Some other warnings can be used to enforce coding
style, and there -Werror could make sense as well (-Werror=vla and
others).
But there are also warnings which are emitted by the GCC middle-end (the
optimizers), and turning on -Werror for those is very problematic.
These warnings are very target-specific and also depend on compiler
version and optimization parameters. Unfortunately that includes the
buffer size warnings based on function attributes (which would otherwise
be a good fit for the kernel because it uses few external headers).
GCC also lacks a facility to suppress warnings if they concern code that
was introduced during optimization and removed again later
(e.g. inlining, constant propagation, dead code removal).
Thanks,
Florian
next prev parent reply other threads:[~2021-09-13 9:50 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-07 18:38 [PATCH] Revert "Enable '-Werror' by default for all kernel builds" Nick Desaulniers
2021-09-07 18:55 ` Fāng-ruì Sòng
2021-09-07 19:16 ` Linus Torvalds
2021-09-07 20:30 ` Nick Desaulniers
2021-09-07 22:14 ` Marco Elver
2021-09-07 22:18 ` Linus Torvalds
2021-09-07 22:33 ` Randy Dunlap
2021-09-13 9:32 ` Pavel Machek
2021-09-13 9:46 ` Greg Kroah-Hartman
2021-09-13 10:02 ` Pavel Machek
2021-09-13 10:51 ` Greg Kroah-Hartman
2021-09-20 16:26 ` Geert Uytterhoeven
2021-09-13 9:50 ` Florian Weimer [this message]
2021-09-13 17:42 ` Linus Torvalds
2021-09-13 14:33 ` Guenter Roeck
2021-09-07 22:28 ` Guenter Roeck
2021-09-07 22:42 ` Segher Boessenkool
2021-09-07 22:55 ` Mark Brown
2021-09-07 23:00 ` Nathan Chancellor
2021-09-07 23:35 ` Mark Brown
2021-09-08 16:12 ` Steven Rostedt
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