From mboxrd@z Thu Jan  1 00:00:00 1970
From: Chao Peng <chao.p.peng@linux.intel.com>
Subject: Re: [PATCH v4 08/12] x86: dynamically get/set CBM for a
 domain
Date: Fri, 10 Apr 2015 15:37:46 +0800
Message-ID: <20150410073746.GE3417@pengc-linux.bj.intel.com>
References: <1428571105-3604-1-git-send-email-chao.p.peng@linux.intel.com>
	<1428571105-3604-9-git-send-email-chao.p.peng@linux.intel.com>
	<5526F7F5.6030508@citrix.com>
Reply-To: Chao Peng <chao.p.peng@linux.intel.com>
Mime-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: 7bit
Return-path: <xen-devel-bounces@lists.xen.org>
Content-Disposition: inline
In-Reply-To: <5526F7F5.6030508@citrix.com>
List-Unsubscribe: <http://lists.xen.org/cgi-bin/mailman/options/xen-devel>,
	<mailto:xen-devel-request@lists.xen.org?subject=unsubscribe>
List-Post: <mailto:xen-devel@lists.xen.org>
List-Help: <mailto:xen-devel-request@lists.xen.org?subject=help>
List-Subscribe: <http://lists.xen.org/cgi-bin/mailman/listinfo/xen-devel>,
	<mailto:xen-devel-request@lists.xen.org?subject=subscribe>
Sender: xen-devel-bounces@lists.xen.org
Errors-To: xen-devel-bounces@lists.xen.org
To: Andrew Cooper <andrew.cooper3@citrix.com>
Cc: keir@xen.org, Ian.Campbell@citrix.com, stefano.stabellini@eu.citrix.com, Ian.Jackson@eu.citrix.com, xen-devel@lists.xen.org, will.auld@intel.com, JBeulich@suse.com, wei.liu2@citrix.com, dgdegra@tycho.nsa.gov
List-Id: xen-devel@lists.xenproject.org

On Thu, Apr 09, 2015 at 11:06:45PM +0100, Andrew Cooper wrote:
> On 09/04/2015 10:18, Chao Peng wrote:
> > +        find->cbm = cbm;
> > +    }
> > +    find->ref++;
> > +    map[old_cos].ref--;
> 
> This can race with psr_free_cos() leading to corruption.  It is possible
> for two different domains to be holding their own spinlock but using the
> same cos index.
> 
> You definitely do need a psr/cos spinlock for safety.

Indeed. Thanks.

Chao