From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail143.messagelabs.com (mail143.messagelabs.com [216.82.254.35]) by kanga.kvack.org (Postfix) with SMTP id ECC6F6B0088 for ; Wed, 10 Nov 2010 11:08:29 -0500 (EST) Date: Wed, 10 Nov 2010 17:02:11 +0100 From: Oleg Nesterov Subject: Re: INFO: suspicious rcu_dereference_check() usage - kernel/pid.c:419 invoked rcu_dereference_check() without protection! Message-ID: <20101110160211.GA2562@redhat.com> References: <20101107182028.GZ15561@linux.vnet.ibm.com> <20101108151509.GA3702@redhat.com> <20101109202900.GV4032@linux.vnet.ibm.com> <20101110155530.GA1905@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20101110155530.GA1905@redhat.com> Sender: owner-linux-mm@kvack.org To: "Paul E. McKenney" Cc: Greg Thelen , linux-kernel@vger.kernel.org, linux-mm@kvack.org, Jens Axboe List-ID: (another try with the proper email address) On 11/09, Paul E. McKenney wrote: > > Thank you, Oleg! Greg, would you be willing to update your patch > to remove the comment? (Perhaps tasklist_lock as well...) Agreed, I think tasklock should be killed. But wait. Whatever we do, isn't this code racy? I do not see why, say, sys_ioprio_set(IOPRIO_WHO_PROCESS) can't install ->io_context after this task has already passed exit_io_context(). Jens, am I missed something? 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 policy in Canada: sign http://dissolvethecrtc.ca/ Don't email: email@kvack.org