Re: [PATCH] netfilter: conntrack: Force inlining of build check to prevent build failure

[Arnd Bergmann]

On Wed, May 3, 2017 at 2:18 PM, Geert Uytterhoeven <geert@xxxxxxxxxxxxxx> wrote:
> If gcc (e.g. 4.1.2) decides not to inline total_extension_size(), the
> build will fail with:
>
>     net/built-in.o: In function `nf_conntrack_init_start':
>     (.text+0x9baf6): undefined reference to `__compiletime_assert_1893'
>
> or
>
>     ERROR: "__compiletime_assert_1893" [net/netfilter/nf_conntrack.ko] undefined!
>
> Fix this by forcing inlining of total_extension_size().
>
> Fixes: b3a5db109e0670d6 ("netfilter: conntrack: use u8 for extension sizes again")
> Signed-off-by: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>

I saw this as well when I tried building with "gcc-7 -Og", and came to the same
conclusion.

Acked-by: Arnd Bergmann <arnd@xxxxxxxx>

With -Og, there were a couple of other instances of BUILD_BUG_ON() failing
to see a compile-time constant, presumably as it fails to inline any functions
that are not explicitly marked inline.

       Arnd