Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752177Ab0LOJgS (ORCPT ); Wed, 15 Dec 2010 04:36:18 -0500 Received: from cn.fujitsu.com ([222.73.24.84]:64538 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1751340Ab0LOJgP (ORCPT ); Wed, 15 Dec 2010 04:36:15 -0500 Message-ID: <4D088C14.1080405@cn.fujitsu.com> Date: Wed, 15 Dec 2010 17:36:20 +0800 From: Li Zefan User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.1b3pre) Gecko/20090513 Fedora/3.0-2.3.beta2.fc11 Thunderbird/3.0b2 MIME-Version: 1.0 To: Andrew Morton CC: Paul Menage , Peter Zijlstra , Hiroyuki KAMEZAWA , Matt Helsley , Stephane Eranian , LKML , containers@lists.linux-foundation.org Subject: [PATCH v2 5/6] cgroups: Triger BUG if a bindable subsystem calls css_get() References: <4D088BB5.30903@cn.fujitsu.com> In-Reply-To: <4D088BB5.30903@cn.fujitsu.com> X-MIMETrack: Itemize by SMTP Server on mailserver/fnst(Release 8.5.1FP4|July 25, 2010) at 2010-12-15 17:36:13, Serialize by Router on mailserver/fnst(Release 8.5.1FP4|July 25, 2010) at 2010-12-15 17:36:13, Serialize complete at 2010-12-15 17:36:13 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2041 Lines: 63 For now unbindable subsystems should not use css_get/put(), so check this misuse. Signed-off-by: Li Zefan --- include/linux/cgroup.h | 7 +++++-- kernel/cgroup.c | 5 +++++ 2 files changed, 10 insertions(+), 2 deletions(-) diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h index 17579b2..e8ad9f1 100644 --- a/include/linux/cgroup.h +++ b/include/linux/cgroup.h @@ -80,13 +80,15 @@ struct cgroup_subsys_state { /* bits in struct cgroup_subsys_state flags field */ enum { - CSS_ROOT, /* This CSS is the root of the subsystem */ - CSS_REMOVED, /* This CSS is dead */ + CSS_ROOT, /* This CSS is the root of the subsystem */ + CSS_REMOVED, /* This CSS is dead */ + CSS_NO_GET, /* Forbid calling css_get/put() */ }; /* Caller must verify that the css is not for root cgroup */ static inline void __css_get(struct cgroup_subsys_state *css, int count) { + BUG_ON(test_bit(CSS_NO_GET, &css->flags)); atomic_add(count, &css->refcnt); } @@ -131,6 +133,7 @@ static inline bool css_tryget(struct cgroup_subsys_state *css) { if (test_bit(CSS_ROOT, &css->flags)) return true; + BUG_ON(test_bit(CSS_NO_GET, &css->flags)); while (!atomic_inc_not_zero(&css->refcnt)) { if (test_bit(CSS_REMOVED, &css->flags)) return false; diff --git a/kernel/cgroup.c b/kernel/cgroup.c index fa2c5de..d49a459 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -938,6 +938,11 @@ static void init_cgroup_css(struct cgroup_subsys_state *css, atomic_set(&css->refcnt, 1); css->flags = 0; css->id = NULL; + + /* For now, unbindable subsystems should not call css_get/put(). */ + if (ss->unbindable) + set_bit(CSS_NO_GET, &css->flags); + if (cgrp == dummytop) set_bit(CSS_ROOT, &css->flags); BUG_ON(cgrp->subsys[ss->subsys_id]); -- 1.6.3 -- 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/