Re: linux-next: build failure after merge of the net-next tree

Masahiro Yamada
2019-06-19T04:03:07Z

Hi.

On Wed, Jun 19, 2019 at 12:23 PM Stephen Rothwell <sfr@canb.auug.org.au> wrote:
>
> Hi all,
>
> After merging the net-next tree, today's linux-next build (x86_64
> allmodconfig) failed like this:
>
> In file included from usr/include/linux/tc_act/tc_ctinfo.hdrtest.c:1:
> ./usr/include/linux/tc_act/tc_ctinfo.h:30:21: error: implicit declaration of function 'BIT' [-Werror=implicit-function-declaration]
> CTINFO_MODE_DSCP = BIT(0),
> ^~~
> ./usr/include/linux/tc_act/tc_ctinfo.h:30:2: error: enumerator value for 'CTINFO_MODE_DSCP' is not an integer constant
> CTINFO_MODE_DSCP = BIT(0),
> ^~~~~~~~~~~~~~~~
> ./usr/include/linux/tc_act/tc_ctinfo.h:32:1: error: enumerator value for 'CTINFO_MODE_CPMARK' is not an integer constant
> };
> ^
>
> Caused by commit
>
> 24ec483cec98 ("net: sched: Introduce act_ctinfo action")
>
> Presumably exposed by commit
>
> b91976b7c0e3 ("kbuild: compile-test UAPI headers to ensure they are self-contained")
>
> from the kbuild tree.

My commit correctly blocked the broken UAPI header, Hooray!

People export more and more headers that
are never able to compile in user-space.

We must block new breakages from coming in.

BIT() is not exported to user-space
since it is not prefixed with underscore.

You can use _BITUL() in user-space,
which is available in include/uapi/linux/const.h

Thanks.

> I have applied the following (obvious) patch for today.
>
> From: Stephen Rothwell <sfr@canb.auug.org.au>
> Date: Wed, 19 Jun 2019 13:15:22 +1000
> Subject: [PATCH] net: sched: don't use BIT() in uapi headers
>
> Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
> ---
> include/uapi/linux/tc_act/tc_ctinfo.h | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/include/uapi/linux/tc_act/tc_ctinfo.h b/include/uapi/linux/tc_act/tc_ctinfo.h
> index da803e05a89b..6166c62dd7dd 100644
> --- a/include/uapi/linux/tc_act/tc_ctinfo.h
> +++ b/include/uapi/linux/tc_act/tc_ctinfo.h
> @@ -27,8 +27,8 @@ enum {
> #define TCA_CTINFO_MAX (__TCA_CTINFO_MAX - 1)
>
> enum {
> - CTINFO_MODE_DSCP = BIT(0),
> - CTINFO_MODE_CPMARK = BIT(1)
> + CTINFO_MODE_DSCP = (1UL << 0),
> + CTINFO_MODE_CPMARK = (1UL << 1)
> };
>
> #endif
> --
> 2.20.1
>
> --
> Cheers,
> Stephen Rothwell

--
Best Regards
Masahiro Yamada