From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754188AbYHSFjI (ORCPT ); Tue, 19 Aug 2008 01:39:08 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752659AbYHSFiw (ORCPT ); Tue, 19 Aug 2008 01:38:52 -0400 Received: from mga11.intel.com ([192.55.52.93]:26119 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752574AbYHSFiv (ORCPT ); Tue, 19 Aug 2008 01:38:51 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.32,233,1217833200"; d="scan'208";a="371764082" Subject: Re: [PATH -mm] Fix a race condtion of oops_in_progress From: Huang Ying To: Andrew Morton Cc: linux-kernel@vger.kernel.org In-Reply-To: <20080818210657.c7f3cd87.akpm@linux-foundation.org> References: <1219025007.5663.22.camel@yhuang-dev.sh.intel.com> <20080818210657.c7f3cd87.akpm@linux-foundation.org> Content-Type: text/plain Date: Tue, 19 Aug 2008 13:38:00 +0800 Message-Id: <1219124280.5663.88.camel@yhuang-dev.sh.intel.com> Mime-Version: 1.0 X-Mailer: Evolution 2.22.3.1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 2008-08-18 at 21:06 -0700, Andrew Morton wrote: > On Mon, 18 Aug 2008 10:03:27 +0800 Huang Ying wrote: > > > This patch fix a race condition of oops_in_progress. Which may be > > changed on multiple CPU simultaneously, but it is changed via > > non-atomic operation ++/--. This patch changes the definition of > > oops_in_process from int to atomic_t, and accessing method to atomic > > operations. > > > > extern atomic_t oops_in_progress; > > In file included from include/asm/system.h:10, > from include/asm/processor.h:17, > from include/asm/atomic_32.h:5, > from include/asm/atomic.h:2, > from include/linux/crypto.h:20, > from arch/x86/kernel/asm-offsets_32.c:7, > from arch/x86/kernel/asm-offsets.c:2: > include/linux/kernel.h:236: error: expected '=', ',', ';', 'asm' or '__attribute__' before 'oops_in_progress' > make[1]: *** [arch/x86/kernel/asm-offsets.s] Error 1 > make: *** [prepare0] Error 2 > > we can't inlude asm/atomic.h from linux/kernel.h because asm/atomic.h > includes linux/kernel.h via the above route. > > And we cannot forward-declare atomic_t by hand because it's a typedef. > > Not sure what to do, really. Find a different header file in which to > declare oops_in_progress? It seems that asm/atomic.h is used for both atomic_t declaration and implementation, how about separate them? That it, add a new file asm/atomic_def.h, put typedef there, and include asm/atomic_def.h in kernel.h? Best Regards, Huang Ying