linux-kernel - Re: [PATCH net-next] compiler: Document behavior compiling with -O0

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Thu, 24 Aug 2017 23:20:18 +0200
From:   Arnd Bergmann <arnd@...db.de>
To:     Joe Stringer <joe@....org>
Cc:     Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Ian Abbott <abbotti@....co.uk>,
        Michal Nazarewicz <mina86@...a86.com>,
        Kees Cook <keescook@...omium.org>
Subject: Re: [PATCH net-next] compiler: Document behavior compiling with -O0

On Thu, Aug 24, 2017 at 6:45 PM, Joe Stringer <joe@....org> wrote:
> Recent changes[0] to make use of __compiletime_assert() from container_of()
> increased the scope of this macro, resulting in a wider set of
> situations where developers cannot compile their code using "-O0". I
> noticed this when making use of the macro in my own development, and
> spent more time than I'd like to admit tracking the problem down. This
> patch documents the behavior in lieu of a compile-time assertion
> implementation that does not rely on optimizations.
>
> Example compilation failure:

Maybe the macro should be enclosed in "#ifdef __OPTIMIZE__"?

Generally speaking we at least rely on function inlining to create a
working kernel, but sometimes there may be a reason to compile a
single file without optimizations.

        Arnd