From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:41066 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934997AbdAEUfx (ORCPT ); Thu, 5 Jan 2017 15:35:53 -0500 Subject: Patch "ppp: defer netns reference release for ppp channel" has been added to the 4.4-stable tree To: xiyou.wangcong@gmail.com, Matt.Bennett@alliedtelesis.co.nz, bmajal222@gmail.com, davem@davemloft.net, g.nault@alphalink.fr, gorcunov@openvz.org, gregkh@linuxfoundation.org, paulus@samba.org Cc: , From: Date: Thu, 05 Jan 2017 21:35:57 +0100 Message-ID: <148364855799124@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: This is a note to let you know that I've just added the patch titled ppp: defer netns reference release for ppp channel to the 4.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: ppp-defer-netns-reference-release-for-ppp-channel.patch and it can be found in the queue-4.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >>From 205e1e255c479f3fd77446415706463b282f94e4 Mon Sep 17 00:00:00 2001 From: WANG Cong Date: Tue, 5 Jul 2016 22:12:36 -0700 Subject: ppp: defer netns reference release for ppp channel From: WANG Cong commit 205e1e255c479f3fd77446415706463b282f94e4 upstream. Matt reported that we have a NULL pointer dereference in ppp_pernet() from ppp_connect_channel(), i.e. pch->chan_net is NULL. This is due to that a parallel ppp_unregister_channel() could happen while we are in ppp_connect_channel(), during which pch->chan_net set to NULL. Since we need a reference to net per channel, it makes sense to sync the refcnt with the life time of the channel, therefore we should release this reference when we destroy it. Fixes: 1f461dcdd296 ("ppp: take reference on channels netns") Reported-by: Matt Bennett Cc: Paul Mackerras Cc: linux-ppp@vger.kernel.org Cc: Guillaume Nault Cc: Cyrill Gorcunov Signed-off-by: Cong Wang Reviewed-by: Cyrill Gorcunov Signed-off-by: David S. Miller Cc: bmajal222 Signed-off-by: Greg Kroah-Hartman --- drivers/net/ppp/ppp_generic.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) --- a/drivers/net/ppp/ppp_generic.c +++ b/drivers/net/ppp/ppp_generic.c @@ -2390,8 +2390,6 @@ ppp_unregister_channel(struct ppp_channe spin_lock_bh(&pn->all_channels_lock); list_del(&pch->list); spin_unlock_bh(&pn->all_channels_lock); - put_net(pch->chan_net); - pch->chan_net = NULL; pch->file.dead = 1; wake_up_interruptible(&pch->file.rwait); @@ -2984,6 +2982,9 @@ ppp_disconnect_channel(struct channel *p */ static void ppp_destroy_channel(struct channel *pch) { + put_net(pch->chan_net); + pch->chan_net = NULL; + atomic_dec(&channel_count); if (!pch->file.dead) { Patches currently in stable-queue which might be from xiyou.wangcong@gmail.com are queue-4.4/ppp-defer-netns-reference-release-for-ppp-channel.patch