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Date:   Tue, 03 Oct 2023 15:40:23 +0200
From:   "Arnd Bergmann" <arnd@arndb.de>
To:     =?UTF-8?Q?Micka=C3=ABl_Sala=C3=BCn?= <mic@digikod.net>,
        "Stephen Rothwell" <sfr@canb.auug.org.au>
Cc:     "Konstantin Meskhidze" <konstantin.meskhidze@huawei.com>,
        "Linux Kernel Mailing List" <linux-kernel@vger.kernel.org>,
        linux-next <linux-next@vger.kernel.org>,
        "Willem de Bruijn" <willemdebruijn.kernel@gmail.com>,
        gnoack3000@gmail.com, linux-security-module@vger.kernel.org,
        Netdev <netdev@vger.kernel.org>, netfilter-devel@vger.kernel.org,
        yusongping@huawei.com, artem.kuzin@huawei.com,
        "Geert Uytterhoeven" <geert@linux-m68k.org>,
        "Randy Dunlap" <rdunlap@infradead.org>
Subject: Re: linux-next: build warning after merge of the landlock tree
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On Tue, Oct 3, 2023, at 15:15, Micka=C3=ABl Sala=C3=BCn wrote:
> PowerPC-64 follows the LP64 data model and then uses int-l64.h (instea=
d of
> int-ll64.h like most architectures) for user space code.
>
> Here is the same code with the (suggested) "%lu" token on x86_86:
>
>   samples/landlock/sandboxer.c: In function =E2=80=98populate_ruleset_=
net=E2=80=99:
>   samples/landlock/sandboxer.c:170:77: error: format =E2=80=98%lu=E2=80=
=99 expects=20
> argument of type =E2=80=98long unsigned int=E2=80=99, but argument 3 h=
as type =E2=80=98__u64=E2=80=99=20
> {aka =E2=80=98long long unsigned int=E2=80=99} [-Werror=3Dformat=3D]
>     170 |                                 "Failed to update the rulese=
t=20
> with port \"%lu\": %s\n",
>         |                                                             =
 =20
>             ~~^
>         |                                                             =
 =20
>               |
>         |                                                             =
 =20
>               long unsigned int
>         |                                                             =
 =20
>             %llu
>     171 |                                 net_port.port,=20
> strerror(errno));
>         |                                 ~~~~~~~~~~~~~
>         |                                         |
>         |                                         __u64 {aka long long=20
> unsigned int}
>
>
> We would then need to cast __u64 to unsigned long long to avoid this w=
arning,
> which may look useless, of even buggy, for people taking a look at thi=
s sample.
>
> Anyway, it makes more sense to cast it to __u16 because it is the
> expected type for a TCP port. I'm updating the patch with that.
> Konstantin, please take this fix for the next series:
> https://git.kernel.org/mic/c/fc9de206a61a
>
>
> On Tue, Oct 03, 2023 at 02:27:37PM +1100, Stephen Rothwell wrote:
>> Hi all,
>>=20
>> After merging the landlock tree, today's linux-next build (powerpc
>> allyesconfig) produced this warning:
>>=20
>> samples/landlock/sandboxer.c: In function 'populate_ruleset_net':
>> samples/landlock/sandboxer.c:170:78: warning: format '%llu' expects a=
rgument of type 'long long unsigned int', but argument 3 has type '__u64=
' {aka 'long unsigned int'} [-Wformat=3D]
>>   170 |                                 "Failed to update the ruleset=
 with port \"%llu\": %s\n"

I think defining the __SANE_USERSPACE_TYPES__ macro should take care of =
this,
then __u64 has the same type as it does in the kernel.

        Arnd