Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755486AbbHYQOR (ORCPT ); Tue, 25 Aug 2015 12:14:17 -0400 Received: from mx1.redhat.com ([209.132.183.28]:55395 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753280AbbHYQOQ (ORCPT ); Tue, 25 Aug 2015 12:14:16 -0400 Date: Tue, 25 Aug 2015 18:11:45 +0200 From: Oleg Nesterov To: Guenter Roeck Cc: Mark Salter , Yoshinori Sato , uclinux-h8-devel@lists.sourceforge.jp, "linux-kernel@vger.kernel.org" , "Peter Zijlstra (Intel)" , "Paul E. McKenney" , Josh Triplett Subject: Re: h8300 build failures in linux-next (in rcu code, gcc 5.x related, not limited to h8300) Message-ID: <20150825161145.GA29908@redhat.com> References: <55DB63AC.7070305@roeck-us.net> <8737z7nc7b.wl-ysato@users.sourceforge.jp> <1440512875.5882.16.camel@redhat.com> <55DC83C7.1060809@roeck-us.net> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <55DC83C7.1060809@roeck-us.net> User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2385 Lines: 77 On 08/25, Guenter Roeck wrote: > > Hi Mark, > > On 08/25/2015 07:27 AM, Mark Salter wrote: >> On Tue, 2015-08-25 at 14:56 +0900, Yoshinori Sato wrote: >>> On Tue, 25 Aug 2015 03:34:20 +0900, >>> Guenter Roeck wrote: >>>> >>>> Hi, >>>> >>>> In linux-next as of today (0824), all h8300 builds fail for me with an >>>> internal >>>> compiler error. >>>> >>>> Building h8300:allnoconfig ... failed >>>> -------------- >>>> Error log: >>>> >>>> In file included from include/linux/rcupdate.h:429:0, >>>> from include/linux/rcusync.h:5, >>>> from kernel/rcu/sync.c:1: >>>> include/linux/rcutiny.h: In function ‘rcu_barrier_sched’: >>>> include/linux/rcutiny.h:55:20: internal compiler error: Segmentation >>>> fault >>>> static inline void rcu_barrier_sched(void) >>>> ^ >>>> >>>> I tried both gcc 5.1 and 5.2, built with the patch set available to me. >>>> >>>> Is there a more recent compiler / patch set available that might fix >>>> the problem ? >>>> >>> >>> No. >>> I tried gcc 6.0. It got same error. >>> It looks optimization problem on h8300 target. >>> I will investigate it. >> >> I get the same ICE with c6x gcc 5.1 >> > > Interesting. h8300 was the only gcc 5+ compiler I had used so far. > Just for fun, I built an alpha toolchain with gcc 5.1. Same problem there. > So it looks like it isn't a h8300 problem after all, it is a gcc problem. > > Updated subject line, and copied rcu maintainers. Damn. This was caused by my patch, I need to react, and I do not know what to say ;) OK, this is gcc bug. But we probably need the workaround, and I don't have a h8300 machine so I can't test the fix. Could you please try to compile kernel/rcu/sync.o with the patch below? Just to know how "stable" this bug is. I expect the compilation should fail again, rcutiny.h:rcu_barrier() is "inline" too. Oleg. --- a/kernel/rcu/sync.c +++ b/kernel/rcu/sync.c @@ -24,7 +24,6 @@ static const struct { [RCU_SCHED_SYNC] = { .sync = synchronize_sched, .call = call_rcu_sched, - .wait = rcu_barrier_sched, __INIT_HELD(rcu_read_lock_sched_held) }, [RCU_BH_SYNC] = { -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/