Re: [PATCH] netfilter: NFT_SOCKET don't use NF_SOCKET_IPV6 without NF_TABLES_IPV6

On Tue, Jul 10, 2018 at 11:10:40AM +0200, Arnd Bergmann wrote:

On Tue, Jul 10, 2018 at 10:05 AM, Máté Eckl [off-list ref] wrote:

quoted

On Tue, Jul 10, 2018 at 10:02:27AM +0200, Máté Eckl wrote:

quoted

On Mon, Jul 09, 2018 at 11:35:09PM +0200, Arnd Bergmann wrote:

quoted

It is now possible to build the nft_socket module as built-in when
NF_TABLES_IPV6 is disabled, and have NF_SOCKET_IPV6=m set manually.

In this case, the NF_SOCKET_IPV6 functionality will be useless according
to the explanation in commit 35bf1ccecaaa ("netfilter: Kconfig: Change
IPv6 select dependencies"), but on top of that it also causes a link
error:

net/netfilter/nft_socket.o: In function `nft_socket_eval':
nft_socket.c:(.text+0x162): undefined reference to `nf_sk_lookup_slow_v6'

This changes the compile-time check so we don't attempt to use
the NF_SOCKET_IPV6 code when it cannot be used, and make it all
compile again. That may lead to unexpected behavior when a user
enables NF_SOCKET_IPV6 but cannot use it, but seems to be the
logical conclusion of the 35bf1ccecaaa change.

Fixes: 35bf1ccecaaa ("netfilter: Kconfig: Change IPv6 select dependencies")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

I think this should be fixed in the Kconfig rather than inside the module(s).

Should we revert your patch then, or do you have a better idea?

Máté, would you resubmit a new patch that addresses all the problems
that Arnd is reporting in one go?

I think it's better if we toss your original patch in the tree and
rebase, ie. take the new one that fixes all issues that Arnd is
reporting. It would be good if we can sort out this before I send the
next pull request for net-next stuff.

I was afraid of fallout like this when I saw your original patch,
kbuild is always tricky.

Please Cc Arnd, Florian and me for review.

Thanks!