From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753662Ab1HHMys (ORCPT ); Mon, 8 Aug 2011 08:54:48 -0400 Received: from mx1.redhat.com ([209.132.183.28]:63317 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752870Ab1HHMyr (ORCPT ); Mon, 8 Aug 2011 08:54:47 -0400 Organization: Red Hat UK Ltd. Registered Address: Red Hat UK Ltd, Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SI4 1TE, United Kingdom. Registered in England and Wales under Company Registration No. 3798903 From: David Howells In-Reply-To: <20110808123442.GF2385@linux.vnet.ibm.com> References: <20110808123442.GF2385@linux.vnet.ibm.com> <20110807175511.GZ2203@ZenIV.linux.org.uk> <13248.1312791509@redhat.com> To: paulmck@linux.vnet.ibm.com Cc: dhowells@redhat.com, Al Viro , Linus Torvalds , linux-kernel@vger.kernel.org Subject: Re: fix rcu annotations noise in cred.h Date: Mon, 08 Aug 2011 13:54:08 +0100 Message-ID: <13642.1312808048@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Paul E. McKenney wrote: > This is indeed what rcu_dereference_protected() is intended for. How about the attached patch? David --- From: David Howells Subject: [PATCH] CRED: Restore const to current_cred() Commit 3295514841c2112d94451ba5deaf54f5afb78ea9 accidentally dropped the const of current->cred inside current_cred() by the insertion of a cast to deal with an RCU annotation loss warning from sparce. Use an appropriate RCU wrapper instead so as not to lose the const. Signed-off-by: David Howells cc: Al Viro --- include/linux/cred.h | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-) diff --git a/include/linux/cred.h b/include/linux/cred.h index 98f46ef..8e2fd44 100644 --- a/include/linux/cred.h +++ b/include/linux/cred.h @@ -269,7 +269,7 @@ static inline void put_cred(const struct cred *_cred) * since nobody else can modify it. */ #define current_cred() \ - (*(__force struct cred **)¤t->cred) + rcu_dereference_protected(current->cred, 1) /** * __task_cred - Access a task's objective credentials