From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752440AbWCPRkl (ORCPT ); Thu, 16 Mar 2006 12:40:41 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752441AbWCPRkl (ORCPT ); Thu, 16 Mar 2006 12:40:41 -0500 Received: from zeus1.kernel.org ([204.152.191.4]:1180 "EHLO zeus1.kernel.org") by vger.kernel.org with ESMTP id S1752440AbWCPRkk (ORCPT ); Thu, 16 Mar 2006 12:40:40 -0500 To: Linus Torvalds Cc: , Andrew Morton , Janak Desai , Al Viro , Christoph Hellwig , Michael Kerrisk , Andi Kleen , Paul Mackerras , Oleg Nesterov Subject: [PATCH] unshare: Use rcu_assign_pointer when setting sighand References: From: ebiederm@xmission.com (Eric W. Biederman) Date: Thu, 16 Mar 2006 10:31:38 -0700 In-Reply-To: (Eric W. Biederman's message of "Thu, 16 Mar 2006 09:49:08 -0700") Message-ID: User-Agent: Gnus/5.1007 (Gnus v5.10.7) Emacs/21.4 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org The sighand pointer only needs the rcu_read_lock on the read side. So only depending on task_lock protection when setting this pointer is not enough. We also need a memory barrier to ensure the initialization is seen first. Use rcu_assign_pointer as it does this for us, and clearly documents that we are setting an rcu readable pointer. Signed-off-by: Eric W. Biederman --- kernel/fork.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-) f0cdb649b7140927777f4355631648b396ee235b diff --git a/kernel/fork.c b/kernel/fork.c index d2706e9..2f24553 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -1573,7 +1573,7 @@ asmlinkage long sys_unshare(unsigned lon if (new_sigh) { sigh = current->sighand; - current->sighand = new_sigh; + rcu_assign_pointer(current->sighand, new_sigh); new_sigh = sigh; } -- 1.2.4.g2d33