From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964959AbWGJNbk (ORCPT ); Mon, 10 Jul 2006 09:31:40 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S964965AbWGJNbk (ORCPT ); Mon, 10 Jul 2006 09:31:40 -0400 Received: from mx1.redhat.com ([66.187.233.31]:31134 "EHLO mx1.redhat.com") by vger.kernel.org with ESMTP id S964959AbWGJNbj (ORCPT ); Mon, 10 Jul 2006 09:31:39 -0400 From: David Howells In-Reply-To: <20060710024657.GA255@oleg> References: <20060710024657.GA255@oleg> To: Oleg Nesterov Cc: David Howells , linux-kernel@vger.kernel.org, Andrew Morton Subject: Re: [PATCH 7/8] FDPIC: Add coredump capability for the ELF-FDPIC binfmt [try #4] X-Mailer: MH-E 8.0; nmh 1.1; GNU Emacs 22.0.50 Date: Mon, 10 Jul 2006 14:31:31 +0100 Message-ID: <10872.1152538291@warthog.cambridge.redhat.com> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Oleg Nesterov wrote: > Do you see any reason for tasklist_lock here (and in elf_core_dump) ? > > do_each_thread() is rcu-safe, and all tasks which use this ->mm must > sleep in wait_for_completion(&mm->core_done) at this point. Hmmm... do_each_thread() does not call rcu_read_lock/unlock(), but you may well be right. What about kernel threads running on another CPU with active_mm set to this mm (assuming I'm remembering correctly how that works)? I'm not sure they'd be a problem, though. It does sound like you've got a valid point, though. David