From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751283AbcCFIhT (ORCPT ); Sun, 6 Mar 2016 03:37:19 -0500 Received: from mx1.redhat.com ([209.132.183.28]:44003 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751138AbcCFIhN (ORCPT ); Sun, 6 Mar 2016 03:37:13 -0500 Date: Sun, 6 Mar 2016 10:37:07 +0200 From: "Michael S. Tsirkin" To: kbuild test robot Cc: kbuild-all@01.org, linux-kernel@vger.kernel.org, linux@lists.openrisc.net, jonas@southpole.se, Philip Li Subject: Re: drivers/vhost/vhost.c:718:3: error: call to '__compiletime_assert_718' declared with attribute error: BUILD_BUG_ON failed: __alignof__ *vq->avail > VRING_AVAIL_ALIGN_SIZE Message-ID: <20160306083707.GA29096@redhat.com> References: <201602280711.3TTbALEV%fengguang.wu@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <201602280711.3TTbALEV%fengguang.wu@intel.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org I keep seeing these errors. Any openrisc/gcc/kbuild people interested in looking into this? On Sun, Feb 28, 2016 at 07:15:14AM +0800, kbuild test robot wrote: > Hi Michael, > > FYI, the error/warning still remains. > > tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master > head: 691429e13dfaf5b0994b07cc166db41bd608ee3d > commit: 5d9a07b0de512b77bf28d2401e5fe3351f00a240 vhost: relax used address alignment > date: 1 year, 2 months ago > config: openrisc-allmodconfig (attached as .config) > reproduce: > wget https://git.kernel.org/cgit/linux/kernel/git/wfg/lkp-tests.git/plain/sbin/make.cross -O ~/bin/make.cross > chmod +x ~/bin/make.cross > git checkout 5d9a07b0de512b77bf28d2401e5fe3351f00a240 > # save the attached .config to linux build tree > make.cross ARCH=openrisc > > All errors (new ones prefixed by >>): > > drivers/vhost/vhost.c: In function 'vhost_vring_ioctl': > >> drivers/vhost/vhost.c:718:3: error: call to '__compiletime_assert_718' declared with attribute error: BUILD_BUG_ON failed: __alignof__ *vq->avail > VRING_AVAIL_ALIGN_SIZE > > vim +/__compiletime_assert_718 +718 drivers/vhost/vhost.c > > 712 (u64)(unsigned long)a.avail_user_addr != a.avail_user_addr) { > 713 r = -EFAULT; > 714 break; > 715 } > 716 > 717 /* Make sure it's safe to cast pointers to vring types. */ > > 718 BUILD_BUG_ON(__alignof__ *vq->avail > VRING_AVAIL_ALIGN_SIZE); > 719 BUILD_BUG_ON(__alignof__ *vq->used > VRING_USED_ALIGN_SIZE); > 720 if ((a.avail_user_addr & (VRING_AVAIL_ALIGN_SIZE - 1)) || > 721 (a.used_user_addr & (VRING_USED_ALIGN_SIZE - 1)) || > > --- > 0-DAY kernel test infrastructure Open Source Technology Center > https://lists.01.org/pipermail/kbuild-all Intel Corporation I still think it's a bug in the openrisc compiler used. struct vring_avail { unsigned short flags; unsigned short idx; }; struct vring_avail *x; int main(int argc, char **argv) { footest(); if (__alignof__(*x) == 1) foo1(); else if (__alignof__(*x) == 2) foo2(); else if (__alignof__(*x) == 4) foo4(); else if (__alignof__(*x) == 8) foo8(); else fooother(); return 0; } when compiled with the openrisc compiler from kernel.org this calls foo4 and it really should call foo2, since the openrisc manual says: 16.1.2 Aggregates and Unions Aggregates (structures and arrays) and unions assume the alignment of their most strictly aligned element. and alignment for unsigned short is 2. -- MST