linux-kernel - Re: [PATCH v2 1/2] sparc,x86: vdso: remove meaningless undefining CONFIG_OPTIMIZE

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]

Message-ID: <20200220174155.GA40621@ubuntu-m2-xlarge-x86>
Date:   Thu, 20 Feb 2020 10:41:55 -0700
From:   Nathan Chancellor <natechancellor@...il.com>
To:     Masahiro Yamada <masahiroy@...nel.org>
Cc:     Andrew Morton <akpm@...ux-foundation.org>,
        Arnd Bergmann <arnd@...db.de>, Ingo Molnar <mingo@...hat.com>,
        Thomas Gleixner <tglx@...utronix.de>, x86@...nel.org,
        clang-built-linux@...glegroups.com,
        Miguel Ojeda <miguel.ojeda.sandonis@...il.com>,
        sparclinux@...r.kernel.org, Andy Lutomirski <luto@...nel.org>,
        Borislav Petkov <bp@...en8.de>,
        "David S. Miller" <davem@...emloft.net>,
        "H. Peter Anvin" <hpa@...or.com>, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 1/2] sparc,x86: vdso: remove meaningless undefining
 CONFIG_OPTIMIZE_INLINING

On Thu, Feb 20, 2020 at 08:08:06PM +0900, Masahiro Yamada wrote:
> The code, #undef CONFIG_OPTIMIZE_INLINING, is not working as expected
> because <linux/compiler_types.h> is parsed before vclock_gettime.c
> since 28128c61e08e ("kconfig.h: Include compiler types to avoid missed
> struct attributes").
> 
> Since then, <linux/compiler_types.h> is included really early by
> using the '-include' option. So, you cannot negate the decision of
> <linux/compiler_types.h> in this way.
> 
> You can confirm it by checking the pre-processed code, like this:
> 
>   $ make arch/x86/entry/vdso/vdso32/vclock_gettime.i
> 
> There is no difference with/without CONFIG_CC_OPTIMIZE_FOR_SIZE.
> 
> It is about two years since 28128c61e08e. Nobody has reported a
> problem (or, nobody has even noticed the fact that this code is not
> working).
> 
> It is ugly and unreliable to attempt to undefine a CONFIG option from
> C files, and anyway the inlining heuristic is up to the compiler.
> 
> Just remove the broken code.
> 
> Signed-off-by: Masahiro Yamada <masahiroy@...nel.org>
> Acked-by: Miguel Ojeda <miguel.ojeda.sandonis@...il.com>

Reviewed-by: Nathan Chancellor <natechancellor@...il.com>