From mboxrd@z Thu Jan 1 00:00:00 1970 From: Guillaume Nault Subject: Re: [regresssion 4.15] Userspace compilation broken by uapi/linux/if_ether.h update Date: Fri, 26 Jan 2018 18:17:23 +0100 Message-ID: <20180126171723.GV1422@alphalink.fr> References: <20180125145819.GT1422@alphalink.fr> <032d01e4-81c8-ad2f-abaf-28a5584e6bef@hauke-m.de> <20180126105138.GU1422@alphalink.fr> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20180126105138.GU1422-pHk1y4uTXVDytLWWfqlThQ@public.gmane.org> Sender: linux-api-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: David Miller , Hauke Mehrtens Cc: netdev-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-api-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-api@vger.kernel.org On Fri, Jan 26, 2018 at 11:51:38AM +0100, Guillaume Nault wrote: > On Thu, Jan 25, 2018 at 11:21:34PM +0100, Hauke Mehrtens wrote: > > On 01/25/2018 03:58 PM, Guillaume Nault wrote: > > > Now that linux/libc-compat.h is included in linux/if_ether.h, it is > > > processed before netinet/in.h. Therefore, it sets the relevant > > > __UAPI_DEF_* guards to 1 (as _NETINET_IN_H isn't yet defined). > > > Then netinet/in.h is included, followed by linux/in.h. The later > > > doesn't realise that what it defines has already been included by > > > netinet/in.h because the __UAPI_DEF_* guards were set too early. > > > > > This is about this commit: > > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=6926e041a8920c8ec27e4e155efa760aa01551fd > > > > On option would be to move this into include/uapi/linux/if_ether.h and > > remove the include for libc-compat.h: > > #ifndef __UAPI_DEF_ETHHDR > > #define __UAPI_DEF_ETHHDR 1 > > #endif > > > > This will only work if netinet/if_ether.h is included before > > linux/if_ether.h, but I think this is very likely. > > > I don't see what makes its likely. That's not directly related to your > point, but for example, glibc guarantees the opposite as it includes > linux/if_ether.h at the beginning of netinet/if_ether.h. > > > I think we can do this because we do not need some special libc handling > > like it is done for other symbols as __UAPI_DEF_ETHHDR is currently only > > needed by musl and not by glibc. > > > That's ok for me as long as existing projects keep compiling. But all > __UAPI_DEF_* are currently centralised in libc-compat.h. Adding > __UAPI_DEF_ETHHDR in if_ether.h looks like defeating the purpose of > libc-compat.h and I wonder if that'd be accepted. Maybe with a > different name. > > In any case, we're really late in the release cycle. If more discussion > is needed, it's probably better to revert and take time to work on a > solution for the next release. > Hi David, I just realise you've sent your last pull request for this release. I was waiting for feedbacks in order to avoid a revert. Should I send a revert now or do you prefer to sort this out later and backport a fix in 4.15.1?