Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759355AbXEWIVx (ORCPT ); Wed, 23 May 2007 04:21:53 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756385AbXEWIVp (ORCPT ); Wed, 23 May 2007 04:21:45 -0400 Received: from wa-out-1112.google.com ([209.85.146.182]:46145 "EHLO wa-out-1112.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756271AbXEWIVo (ORCPT ); Wed, 23 May 2007 04:21:44 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=beta; h=received:message-id:date:from:user-agent:mime-version:to:cc:subject:references:in-reply-to:x-enigmail-version:content-type:content-transfer-encoding; b=X77uD2fZjFbWzHT4d/VJL0clWtlQpTMIFDHP416HNReWKQpv16Zz3YU0c1MKGE+8LA7LB5ycuT/ATYDLZl5ediDq3+8qXZ3ZA4AtvwBZxb6lEI1kP3SiY/q9WGkPnmKkGrk5ukrsw6MX88pgMaQjbkqvWfVZpqTvlByrgsjIJZ8= Message-ID: <4653F98A.8080308@gmail.com> Date: Wed, 23 May 2007 10:21:30 +0200 From: Tejun Heo User-Agent: Thunderbird 2.0.0.0 (X11/20070326) MIME-Version: 1.0 To: Greg KH CC: Maneesh Soni , Andrew Morton , Clemens Schwaighofer , linux-kernel , Dipankar Sarma , Chuck Ebbert Subject: Re: [PATCH 2/2] sysfs: fix race condition around sd->s_dentry, take#2 References: <20070516082935.fe112ab5.akpm@linux-foundation.org> <464B2605.9040200@gmail.com> <20070516091346.3c76cb46.akpm@linux-foundation.org> <464B4DE4.9060100@gmail.com> <20070517120423.GE17712@kroah.com> <20070517173912.GA14370@in.ibm.com> <464C95AB.3020209@gmail.com> <464C9801.8000606@gmail.com> <464C9BEA.7060309@gmail.com> <20070521050101.GC9214@in.ibm.com> <20070522223841.GB2874@kroah.com> In-Reply-To: <20070522223841.GB2874@kroah.com> X-Enigmail-Version: 0.95.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1534 Lines: 35 Greg KH wrote: > On Mon, May 21, 2007 at 10:31:01AM +0530, Maneesh Soni wrote: >> On Thu, May 17, 2007 at 08:16:10PM +0200, Tejun Heo wrote: >>> Allowing attribute and symlink dentries to be reclaimed means >>> sd->s_dentry can change dynamically. However, updates to the field >>> are unsynchronized leading to race conditions. This patch adds >>> sysfs_lock and use it to synchronize updates to sd->s_dentry. >>> >>> Due to the locking around ->d_iput, the check in sysfs_drop_dentry() >>> is complex. sysfs_lock only protect sd->s_dentry pointer itself. The >>> validity of the dentry is protected by dcache_lock, so whether dentry >>> is alive or not can only be tested while holding both locks. >>> >>> This is minimal backport of sysfs_drop_dentry() rewrite in devel >>> branch. >>> >>> DONT APPLY JUST YET >> Looks ok to me.. I have tested it it but unfortunately I couldn't >> recreate the race without the patch also. It would be helpful if >> people actually seeing the race, provide the test results. >> >> Greg, please merge this one once we have some test results. > > Can someone just resend it after those test results are in, with the > proper signed-off-by, so I know it's safe to apply? I'll resend with S-O-B after someone verifies it fixes the problem. -- tejun - 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/