From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965830AbbCPPc6 (ORCPT ); Mon, 16 Mar 2015 11:32:58 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:55131 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756711AbbCPORA (ORCPT ); Mon, 16 Mar 2015 10:17:00 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Al Viro Subject: [PATCH 3.19 099/177] debugfs: leave freeing a symlink body until inode eviction Date: Mon, 16 Mar 2015 15:08:26 +0100 Message-Id: <20150316140817.596085642@linuxfoundation.org> X-Mailer: git-send-email 2.3.3 In-Reply-To: <20150316140813.085032723@linuxfoundation.org> References: <20150316140813.085032723@linuxfoundation.org> User-Agent: quilt/0.64 MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.19-stable review patch. If anyone has any objections, please let me know. ------------------ From: Al Viro commit 0db59e59299f0b67450c5db21f7f316c8fb04e84 upstream. As it is, we have debugfs_remove() racing with symlink traversals. Supply ->evict_inode() and do freeing there - inode will remain pinned until we are done with the symlink body. And rip the idiocy with checking if dentry is positive right after we'd verified debugfs_positive(), which is a stronger check... Signed-off-by: Al Viro Signed-off-by: Greg Kroah-Hartman --- fs/debugfs/inode.c | 34 +++++++++++++++++----------------- 1 file changed, 17 insertions(+), 17 deletions(-) --- a/fs/debugfs/inode.c +++ b/fs/debugfs/inode.c @@ -246,10 +246,19 @@ static int debugfs_show_options(struct s return 0; } +static void debugfs_evict_inode(struct inode *inode) +{ + truncate_inode_pages_final(&inode->i_data); + clear_inode(inode); + if (S_ISLNK(inode->i_mode)) + kfree(inode->i_private); +} + static const struct super_operations debugfs_super_operations = { .statfs = simple_statfs, .remount_fs = debugfs_remount, .show_options = debugfs_show_options, + .evict_inode = debugfs_evict_inode, }; static int debug_fill_super(struct super_block *sb, void *data, int silent) @@ -466,23 +475,14 @@ static int __debugfs_remove(struct dentr int ret = 0; if (debugfs_positive(dentry)) { - if (dentry->d_inode) { - dget(dentry); - switch (dentry->d_inode->i_mode & S_IFMT) { - case S_IFDIR: - ret = simple_rmdir(parent->d_inode, dentry); - break; - case S_IFLNK: - kfree(dentry->d_inode->i_private); - /* fall through */ - default: - simple_unlink(parent->d_inode, dentry); - break; - } - if (!ret) - d_delete(dentry); - dput(dentry); - } + dget(dentry); + if (S_ISDIR(dentry->d_inode->i_mode)) + ret = simple_rmdir(parent->d_inode, dentry); + else + simple_unlink(parent->d_inode, dentry); + if (!ret) + d_delete(dentry); + dput(dentry); } return ret; }