Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753520Ab0LHHCa (ORCPT ); Wed, 8 Dec 2010 02:02:30 -0500 Received: from fgwmail7.fujitsu.co.jp ([192.51.44.37]:34558 "EHLO fgwmail7.fujitsu.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751618Ab0LHHC2 convert rfc822-to-8bit (ORCPT ); Wed, 8 Dec 2010 02:02:28 -0500 X-SecurityPolicyCheck-FJ: OK by FujitsuOutboundMailChecker v1.3.1 From: KOSAKI Motohiro To: akpm@linux-foundation.org Subject: Re: [merged] mm-mempolicyc-add-rcu-read-lock-to-protect-pid-structure.patch removed from -mm tree Cc: kosaki.motohiro@jp.fujitsu.com, zengzm.kernel@gmail.com, cl@linux-foundation.org, paulmck@us.ibm.com, mm-commits@vger.kernel.org, Peter Zijlstra , LKML , linux-mm In-Reply-To: <201012071948.oB7Jm78B004585@imap1.linux-foundation.org> References: <201012071948.oB7Jm78B004585@imap1.linux-foundation.org> Message-Id: <20101208160009.173F.A69D9226@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 8BIT X-Mailer: Becky! ver. 2.50.07 [ja] Date: Wed, 8 Dec 2010 16:02:26 +0900 (JST) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2464 Lines: 75 > > The patch titled > mm/mempolicy.c: add rcu read lock to protect pid structure > has been removed from the -mm tree. Its filename was > mm-mempolicyc-add-rcu-read-lock-to-protect-pid-structure.patch > > This patch was dropped because it was merged into mainline or a subsystem tree > > The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/ > > ------------------------------------------------------ > Subject: mm/mempolicy.c: add rcu read lock to protect pid structure > From: Zeng Zhaoming > > find_task_by_vpid() should be protected by rcu_read_lock(), to prevent > free_pid() reclaiming pid. > > Signed-off-by: Zeng Zhaoming > Cc: "Paul E. McKenney" > Cc: KOSAKI Motohiro > Cc: Christoph Lameter > Signed-off-by: Andrew Morton Andrew, please consider pick following patch too. =========================================================================== >From 9de9f70f74e55d92b5e9057e22fc629405f63295 Mon Sep 17 00:00:00 2001 From: KOSAKI Motohiro Date: Thu, 16 Dec 2010 17:49:23 +0900 Subject: [PATCH] mempolicy: remove tasklist_lock from migrate_pages Today, tasklist_lock in migrate_pages doesn't protect anything. rcu_read_lock() provide enough protection from pid hash walk. Reported-by: Peter Zijlstra Cc: Christoph Lameter Signed-off-by: KOSAKI Motohiro --- mm/mempolicy.c | 3 --- 1 files changed, 0 insertions(+), 3 deletions(-) diff --git a/mm/mempolicy.c b/mm/mempolicy.c index 11ff260..9064945 100644 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -1308,16 +1308,13 @@ SYSCALL_DEFINE4(migrate_pages, pid_t, pid, unsigned long, maxnode, /* Find the mm_struct */ rcu_read_lock(); - read_lock(&tasklist_lock); task = pid ? find_task_by_vpid(pid) : current; if (!task) { - read_unlock(&tasklist_lock); rcu_read_unlock(); err = -ESRCH; goto out; } mm = get_task_mm(task); - read_unlock(&tasklist_lock); rcu_read_unlock(); err = -EINVAL; -- 1.6.5.2 -- 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/