From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932334AbXCKLqC (ORCPT ); Sun, 11 Mar 2007 07:46:02 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S933267AbXCKLqC (ORCPT ); Sun, 11 Mar 2007 07:46:02 -0400 Received: from mailhub.sw.ru ([195.214.233.200]:23319 "EHLO relay.sw.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932334AbXCKLqA (ORCPT ); Sun, 11 Mar 2007 07:46:00 -0400 Date: Sun, 11 Mar 2007 14:52:44 +0300 From: Alexey Dobriyan To: akpm@osdl.org Cc: "Darrick J. Wong" , linux-kernel@vger.kernel.org, devel@openvz.org Subject: [PATCH -mm] Fix race between proc_readdir and remove_proc_entry Message-ID: <20070311115243.GA6823@localhost.sw.ru> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.11 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org > -procfs-fix-race-between-proc_readdir-and-remove_proc_entry.patch > +fix-race-between-proc_get_inode-and-remove_proc_entry.patch > > Updated. Looks sane. Why have you dropped the first patch? Resending slightly fixed version of it. [PATCH -mm] Fix race between proc_readdir and remove_proc_entry From: "Darrick J. Wong" Fix the following race: proc_readdir remove_proc_entry ============ ================= spin_lock(&proc_subdir_lock); [choose PDE to start filldir from] spin_unlock(&proc_subdir_lock); spin_lock(&proc_subdir_lock); [find PDE] [free PDE, refcount is 0] spin_unlock(&proc_subdir_lock); /* boom */ if (filldir(dirent, de->name, ... [de_put on error path --adobriyan] Signed-off-by: Darrick J. Wong Signed-off-by: Alexey Dobriyan --- fs/proc/generic.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) --- a/fs/proc/generic.c +++ b/fs/proc/generic.c @@ -478,14 +478,21 @@ int proc_readdir(struct file * filp, } do { + struct proc_dir_entry *next; + /* filldir passes info to user space */ + de_get(de); spin_unlock(&proc_subdir_lock); if (filldir(dirent, de->name, de->namelen, filp->f_pos, - de->low_ino, de->mode >> 12) < 0) + de->low_ino, de->mode >> 12) < 0) { + de_put(de); goto out; + } spin_lock(&proc_subdir_lock); filp->f_pos++; - de = de->next; + next = de->next; + de_put(de); + de = next; } while (de); spin_unlock(&proc_subdir_lock); }