From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1763197AbXHEJug (ORCPT ); Sun, 5 Aug 2007 05:50:36 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753929AbXHEJu1 (ORCPT ); Sun, 5 Aug 2007 05:50:27 -0400 Received: from 1wt.eu ([62.212.114.60]:1152 "EHLO 1wt.eu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753039AbXHEJu1 (ORCPT ); Sun, 5 Aug 2007 05:50:27 -0400 Date: Sun, 5 Aug 2007 11:49:16 +0200 From: Willy Tarreau To: Axel Reinhold Cc: linux-kernel@vger.kernel.org Subject: Re: Kernel Bug in 2.4.35 when compiled gcc>=4.2.0 and -march=c3 Message-ID: <20070805094916.GE6002@1wt.eu> References: <200708050856.l758u4ou031651@bongo.freakout.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <200708050856.l758u4ou031651@bongo.freakout.de> User-Agent: Mutt/1.5.11 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Aug 05, 2007 at 10:56:04AM +0200, Axel Reinhold wrote: > i found a bug in linux-2.4.35. > > the bug produces a crashing kernel when compiled > with gcc >=4.2.0 and VIA C3 optimized -march=c3 > (CONFIG_MCYRIXIII=y) > > this issue was first discussed on the gcc bugzilla: > http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32264 > > and tracked down to the include/asm-i386/hw_irq.h > module with the help of the gcc guys: > > (pluto at agmk dot net) wrote: > >yup, i see something new :) > > > >please look at line 12137 of i8259.i: > > > >__attribute__((regparm(0))) void call_do_IRQ(void); __asm__(... > > > >as you can see there is a semicolon after call_do_IRQ(void) > >and following asm statement isn't treated as a function body. > >in this way -O1 -f{no-}unit-at-a-time accidentally produces > >different code. it's not a gcc bug. > > > >linux-2.4.35/include/asm-i386/hw_irq.h > >contains these evil macros. > > is there a chance to fix this? > these macros a far beyond my capabilities to fix. That's one of the ugliest things I've discovered to date ! I have no idea how to fix it, I'm downloading gcc-4.2 right now to try to find a solution. I've never compiled 2.4 with gcc 4.2, so there may be surprises. Regards, Willy