Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757478AbZGFHoo (ORCPT ); Mon, 6 Jul 2009 03:44:44 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753702AbZGFHof (ORCPT ); Mon, 6 Jul 2009 03:44:35 -0400 Received: from acsinet11.oracle.com ([141.146.126.233]:41786 "EHLO acsinet11.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753365AbZGFHoe (ORCPT ); Mon, 6 Jul 2009 03:44:34 -0400 Message-ID: <4A51AAFB.1000601@oracle.com> Date: Mon, 06 Jul 2009 15:42:51 +0800 From: Tao Ma User-Agent: Thunderbird 2.0.0.22 (X11/20090608) MIME-Version: 1.0 To: Amerigo Wang CC: linux-kernel@vger.kernel.org, Jeff Mahoney , Yan Zheng , Josef Bacik , Arjan , Chris Mason , akpm@linux-foundation.org, linux-btrfs@vger.kernel.org, Sven Wegener Subject: Re: [Patch v2] btrfs: use file_remove_suid() after i_mutex is held References: <20090706072043.6555.13669.sendpatchset@localhost.localdomain> In-Reply-To: <20090706072043.6555.13669.sendpatchset@localhost.localdomain> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Source-IP: abhmt007.oracle.com [141.146.116.16] X-Auth-Type: Internal IP X-CT-RefId: str=0001.0A010209.4A51AB02.00B4:SCFSTAT5015188,ss=1,fgs=0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1464 Lines: 43 Hi Amerigo, Amerigo Wang wrote: > V1 -> V2: > Move kmalloc() before mutex_lock(), suggested by Arjan. > > file_remove_suid() should be called with i_mutex held, > file_update_time() too. So move them after mutex_lock(). > > Plus, check the return value of kmalloc(). > > Signed-off-by: WANG Cong > Cc: Arjan > Cc: Chris Mason > Cc: Yan Zheng > Cc: Sven Wegener > Cc: Josef Bacik > Cc: Jeff Mahoney > > --- > diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c > index 7c3cd24..09ef5d6 100644 > --- a/fs/btrfs/file.c > +++ b/fs/btrfs/file.c > @@ -944,14 +944,17 @@ static ssize_t btrfs_file_write(struct file *file, const char __user *buf, > if (count == 0) > goto out_nolock; > > + pages = kmalloc(nrptrs * sizeof(struct page *), GFP_KERNEL); > + if (!pages) > + goto out_nolock; I guess you need to set err to -ENOMEM here so that the caller knows what's wrong. With your patch, this function just return 0(since num_written and err are both 0) with no error, and I guess it is worse than kernel BUG out when the NULL pages is used later. Regards, Tao -- 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/