From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757042AbXD0TPy (ORCPT ); Fri, 27 Apr 2007 15:15:54 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1757171AbXD0TPv (ORCPT ); Fri, 27 Apr 2007 15:15:51 -0400 Received: from mx2.suse.de ([195.135.220.15]:35224 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757038AbXD0S5A (ORCPT ); Fri, 27 Apr 2007 14:57:00 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Oliver Neukum , Greg Kroah-Hartman Subject: [PATCH 12/46] kref: fix CPU ordering with respect to krefs Date: Fri, 27 Apr 2007 11:53:26 -0700 Message-Id: <11777000814075-git-send-email-gregkh@suse.de> X-Mailer: git-send-email 1.5.1.2 In-Reply-To: <11777000773819-git-send-email-gregkh@suse.de> References: <20070427185152.GA17121@kroah.com> <1177700040520-git-send-email-gregkh@suse.de> <11777000433552-git-send-email-gregkh@suse.de> <11777000471977-git-send-email-gregkh@suse.de> <11777000511784-git-send-email-gregkh@suse.de> <11777000552084-git-send-email-gregkh@suse.de> <1177700059319-git-send-email-gregkh@suse.de> <11777000632194-git-send-email-gregkh@suse.de> <11777000663361-git-send-email-gregkh@suse.de> <1177700070961-git-send-email-gregkh@suse.de> <1177700074272-git-send-email-gregkh@suse.de> <11777000773819-git-send-email-gregkh@suse.de> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org From: Oliver Neukum some atomic operations are only atomic, not ordered. Thus a CPU is allowed to reorder memory references to an object to before the reference is obtained. This fixes it. Signed-off-by: Oliver Neukum Signed-off-by: Greg Kroah-Hartman --- lib/kref.c | 2 ++ 1 files changed, 2 insertions(+), 0 deletions(-) diff --git a/lib/kref.c b/lib/kref.c index 0d07cc3..a6dc3ec 100644 --- a/lib/kref.c +++ b/lib/kref.c @@ -21,6 +21,7 @@ void kref_init(struct kref *kref) { atomic_set(&kref->refcount,1); + smp_mb(); } /** @@ -31,6 +32,7 @@ void kref_get(struct kref *kref) { WARN_ON(!atomic_read(&kref->refcount)); atomic_inc(&kref->refcount); + smp_mb__after_atomic_inc(); } /** -- 1.5.1.2