Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753231Ab1DTAjF (ORCPT ); Tue, 19 Apr 2011 20:39:05 -0400 Received: from fgwmail6.fujitsu.co.jp ([192.51.44.36]:37650 "EHLO fgwmail6.fujitsu.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752157Ab1DTAjC (ORCPT ); Tue, 19 Apr 2011 20:39:02 -0400 X-SecurityPolicyCheck-FJ: OK by FujitsuOutboundMailChecker v1.3.1 From: KOSAKI Motohiro To: David Rientjes Subject: Re: [PATCH 1/2] break out page allocation warning code Cc: kosaki.motohiro@jp.fujitsu.com, Dave Hansen , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Johannes Weiner , Michal Nazarewicz , Andrew Morton In-Reply-To: References: <20110419094422.9375.A69D9226@jp.fujitsu.com> Message-Id: <20110420093900.45F6.A69D9226@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit X-Mailer: Becky! ver. 2.56.05 [ja] Date: Wed, 20 Apr 2011 09:39:00 +0900 (JST) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 936 Lines: 28 > On Tue, 19 Apr 2011, KOSAKI Motohiro wrote: > > > The rule is, > > > > 1) writing comm > > need task_lock > > 2) read _another_ thread's comm > > need task_lock > > 3) read own comm > > no need task_lock > > > > That was true a while ago, but you now need to protect every thread's > ->comm with get_task_comm() or ensuring task_lock() is held to protect > against /proc/pid/comm which can change other thread's ->comm. That was > different before when prctl(PR_SET_NAME) would only operate on current, so > no lock was needed when reading current->comm. Right. /proc/pid/comm is evil. We have to fix it. otherwise we need change all of current->comm user. It's very lots! -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/