From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail172.messagelabs.com (mail172.messagelabs.com [216.82.254.3]) by kanga.kvack.org (Postfix) with SMTP id 4590D6B0069 for ; Tue, 1 Nov 2011 11:27:54 -0400 (EDT) Date: Tue, 1 Nov 2011 16:23:20 +0100 From: Oleg Nesterov Subject: Re: Issue with core dump Message-ID: <20111101152320.GA30466@redhat.com> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: owner-linux-mm@kvack.org List-ID: To: trisha yad Cc: linux-mm , Russell King - ARM Linux , linux-kernel@vger.kernel.org, linux-mips@linux-mips.org, kamezawa.hiroyu@jp.fujitsu.com, mhocko@suse.cz, rientjes@google.com, Andrew Morton , Konstantin Khlebnikov , KOSAKI Motohiro , "Rafael J. Wysocki" , Rusty Russell , Tejun Heo On 11/01, trisha yad wrote: > > Dear all, > > I am running a multithreaded application. So consider a global > variable x which is used by a, b and c thread. > > In thread 'a' do abnormal operation(invalid memory access) and kernel > send signal kill to it. In the mean time Thread 'b' and Thread 'c' > got schedule and update > the variable x. when I got the core file, variable x got updated, and > I am not getting actual value that is present at time of crash of > thread a. > But In core file I got updated value of x. I want In core file exact > the same memory status as it at time of abnormal operation(invalid > memory access) Yes, this is possible. > Is there any solution for such problem. ? > > I want in core dump the same status of memory as at time of abnormal > operation(invalid memory access). I don't think we can "fix" this. We can probably change complete_signal() to notify other threads "immediately", but this is not simple and obviously can not close the window completely. Whatever we do, we can't "stop" other threads at the time when thread 'a' traps. All we can do is to try to shrink the window. Oleg. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org