Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759868AbcLAPW6 (ORCPT ); Thu, 1 Dec 2016 10:22:58 -0500 Received: from mx1.redhat.com ([209.132.183.28]:49040 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753591AbcLAPW5 (ORCPT ); Thu, 1 Dec 2016 10:22:57 -0500 Subject: Re: Odd build breakage in 4.9-rc7 To: Prarit Bhargava , Nicolas Pitre , Linus Torvalds References: <20161130172435.GG8563@redhat.com> <583F1A5A.7040708@redhat.com> <583F1F6A.5010307@redhat.com> <58402D96.9020101@redhat.com> Cc: Linux Kernel Mailing List , Tony Luck , zarniwhoop73@googlemail.com, Linux Kbuild mailing list From: Jarod Wilson Message-ID: Date: Thu, 1 Dec 2016 10:22:55 -0500 User-Agent: Mutt/1.5.21 (2010-09-15) MIME-Version: 1.0 In-Reply-To: <58402D96.9020101@redhat.com> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.27]); Thu, 01 Dec 2016 15:22:56 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2755 Lines: 81 On 2016-12-01 9:03 AM, Prarit Bhargava wrote: > > > On 11/30/2016 05:41 PM, Nicolas Pitre wrote: >> On Wed, 30 Nov 2016, Linus Torvalds wrote: >> >>> On Wed, Nov 30, 2016 at 10:50 AM, Prarit Bhargava wrote: >>>> >>>> It comes back. The steps to reproduce this are: >>>> >>>> 1. checkout latest linux.git >>>> 2. make -j112 >>>> >>>> (IOW, it occurs 100% of the time for me on a clean tree.) >> >> I don't have access to such hardware where -j112 could ever make sense. :-) >> In other words, I can't reproduce regardless of the -j value I try. >> >>> I suspect it's not new, it's just that you are able to hit the timing >>> just right (and the new include presumable makes that just be much >>> easier). >> >> Here's the best fix I can think of. I can't convince myself any other >> location would be 100% safe. Obviously I can't confirm if this actually >> fixes anything. >> >> ----- >8 >> Subject: kbuild: make sure autoksyms.h exists early >> >> Some people are able to trigger a race where autoksyms.h is used before >> its empty version is even created. Let's create it at the same time as >> the directory holding it is created. >> >> Signed-off-by: Nicolas Pitre >> >> diff --git a/Makefile b/Makefile >> index 694111b43c..9f9c3b577c 100644 >> --- a/Makefile >> +++ b/Makefile >> @@ -1019,8 +1019,6 @@ prepare2: prepare3 prepare-compiler-check outputmakefile asm-generic >> prepare1: prepare2 $(version_h) include/generated/utsrelease.h \ >> include/config/auto.conf >> $(cmd_crmodverdir) >> - $(Q)test -e include/generated/autoksyms.h || \ >> - touch include/generated/autoksyms.h >> >> archprepare: archheaders archscripts prepare1 scripts_basic >> >> diff --git a/scripts/kconfig/Makefile b/scripts/kconfig/Makefile >> index ebced77deb..90a091b6ae 100644 >> --- a/scripts/kconfig/Makefile >> +++ b/scripts/kconfig/Makefile >> @@ -35,6 +35,8 @@ nconfig: $(obj)/nconf >> >> silentoldconfig: $(obj)/conf >> $(Q)mkdir -p include/config include/generated >> + $(Q)test -e include/generated/autoksyms.h || \ >> + touch include/generated/autoksyms.h >> $< $(silent) --$@ $(Kconfig) >> >> localyesconfig localmodconfig: $(obj)/streamline_config.pl $(obj)/conf >> > > The testing was successful. > > After testing an hour of builds with different -j values, I'm no longer seeing > any compile issues when this patch is applied. When I remove the patch the > compile error returns so I'm going to say that this patch fixed it. > > Thanks again Nicolas. > > Tested-by: Prarit Bhargava Looks good here as well, can do parallel make w/o reverting Tony's patches again. Tested-by: Jarod Wilson -- Jarod Wilson jarod@redhat.com