From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756365AbbEBUem (ORCPT ); Sat, 2 May 2015 16:34:42 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:45892 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1947164AbbEBTfc (ORCPT ); Sat, 2 May 2015 15:35:32 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, "Eric W. Biederman" Subject: [PATCH 3.19 094/177] mnt: Dont propagate umounts in __detach_mounts Date: Sat, 2 May 2015 21:01:56 +0200 Message-Id: <20150502190123.706304190@linuxfoundation.org> X-Mailer: git-send-email 2.3.7 In-Reply-To: <20150502190119.666291882@linuxfoundation.org> References: <20150502190119.666291882@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: "Eric W. Biederman" commit 8318e667f176f7ea34451a1a530634e293f216ac upstream. Invoking mount propagation from __detach_mounts is inefficient and wrong. It is inefficient because __detach_mounts already walks the list of mounts that where something needs to be done, and mount propagation walks some subset of those mounts again. It is actively wrong because if the dentry that is passed to __detach_mounts is not part of the path to a mount that mount should not be affected. change_mnt_propagation(p,MS_PRIVATE) modifies the mount propagation tree of a master mount so it's slaves are connected to another master if possible. Which means even removing a mount from the middle of a mount tree with __detach_mounts will not deprive any mount propagated mount events. Signed-off-by: "Eric W. Biederman" Signed-off-by: Greg Kroah-Hartman --- fs/namespace.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/fs/namespace.c +++ b/fs/namespace.c @@ -1497,7 +1497,7 @@ void __detach_mounts(struct dentry *dent lock_mount_hash(); while (!hlist_empty(&mp->m_list)) { mnt = hlist_entry(mp->m_list.first, struct mount, mnt_mp_list); - umount_tree(mnt, UMOUNT_PROPAGATE); + umount_tree(mnt, 0); } unlock_mount_hash(); put_mountpoint(mp);