From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Wed, 15 May 2002 16:12:50 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Wed, 15 May 2002 16:11:36 -0400 Received: from [195.39.17.254] ([195.39.17.254]:33943 "EHLO Elf.ucw.cz") by vger.kernel.org with ESMTP id ; Wed, 15 May 2002 16:10:33 -0400 Date: Wed, 15 May 2002 14:04:48 +0000 From: Pavel Machek To: "Vamsi Krishna S ." Cc: "Gross, Mark" , "'Erich Focht'" , Linus Torvalds , linux-kernel@vger.kernel.org, "'Bharata B Rao'" Subject: Re: PATCH Multithreaded core dump support for the 2.5.14 (and 15) kernel. Message-ID: <20020515140448.C37@toy.ucw.cz> In-Reply-To: <59885C5E3098D511AD690002A5072D3C057B485B@orsmsx111.jf.intel.com> <20020515120722.A17644@in.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Mailer: Mutt 1.0.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Hi! > To respond to your specific question, if a thread happens to be in > kernel mode when some other thread is dumping core (capturing > register state of other threads, to be more accurate) then > we would capture the _user mode_ register of that thread from the > bottom of it's kernel stack. GDB will show back trace untill the > thread entered kernel (int 0x80), eip will be pointing to the > instruction after the system call (return address). Okay, what about: Thread 1 is in kernel and holds lock A. You need lock A to dump state. When you move 1 to phantom runqueue, you loose ability to get A and deadlock. What prevents that? Pavel -- Philips Velo 1: 1"x4"x8", 300gram, 60, 12MB, 40bogomips, linux, mutt, details at http://atrey.karlin.mff.cuni.cz/~pavel/velo/index.html.