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From:   Andy Lutomirski <luto@kernel.org>
Date:   Tue, 1 Dec 2020 09:23:24 -0800
Message-ID: <CALCETrWZ5eH=0Rjd-vBFRtk-tFQ3tN8_rReaKdVbSm78PFQ7_g@mail.gmail.com>
Subject: Re: [PATCH] fanotify: Fix sys_fanotify_mark() on native x86-32
To:     Brian Gerst <brgerst@gmail.com>
Cc:     LKML <linux-kernel@vger.kernel.org>, X86 ML <x86@kernel.org>,
        Andy Lutomirski <luto@kernel.org>,
        Borislav Petkov <bp@alien8.de>,
        Thomas Gleixner <tglx@linutronix.de>, Jan Kara <jack@suse.cz>,
        =?UTF-8?Q?Pawe=C5=82_Jasiak?= <pawel@jasiak.xyz>
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On Mon, Nov 30, 2020 at 2:31 PM Brian Gerst <brgerst@gmail.com> wrote:
>
> Commit 121b32a58a3a converted native x86-32 which take 64-bit arguments t=
o
> use the compat handlers to allow conversion to passing args via pt_regs.
> sys_fanotify_mark() was however missed, as it has a general compat handle=
r.
> Add a config option that will use the syscall wrapper that takes the spli=
t
> args for native 32-bit.
>
> Reported-by: Pawe=C5=82 Jasiak <pawel@jasiak.xyz>
> Fixes: 121b32a58a3a ("x86/entry/32: Use IA32-specific wrappers for syscal=
ls taking 64-bit arguments")
> Signed-off-by: Brian Gerst <brgerst@gmail.com>
> ---
>  arch/Kconfig                       |  6 ++++++
>  arch/x86/Kconfig                   |  1 +
>  fs/notify/fanotify/fanotify_user.c | 17 +++++++----------
>  include/linux/syscalls.h           | 24 ++++++++++++++++++++++++
>  4 files changed, 38 insertions(+), 10 deletions(-)
>
> diff --git a/arch/Kconfig b/arch/Kconfig
> index 090ef3566c56..452cc127c285 100644
> --- a/arch/Kconfig
> +++ b/arch/Kconfig
> @@ -1045,6 +1045,12 @@ config HAVE_STATIC_CALL_INLINE
>         bool
>         depends on HAVE_STATIC_CALL
>
> +config ARCH_SPLIT_ARG64
> +       bool
> +       help
> +          If a 32-bit architecture requires 64-bit arguments to be split=
 into
> +          pairs of 32-bit arguemtns, select this option.

You misspelled arguments.  You might also want to clarify that, for
64-bit arches, this means that compat syscalls split their arguments.

Aside from that:

Acked-by: Andy Lutomirski <luto@kernel.org>