From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:57772 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932367AbcLHGWh (ORCPT ); Thu, 8 Dec 2016 01:22:37 -0500 Subject: Patch "net: dsa: fix unbalanced dsa_switch_tree reference counting" has been added to the 4.8-stable tree To: nikita.yoush@cogentembedded.com, andrew@lunn.ch, davem@davemloft.net, gregkh@linuxfoundation.org Cc: , From: Date: Thu, 08 Dec 2016 07:20:59 +0100 Message-ID: <148117805948140@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 net: dsa: fix unbalanced dsa_switch_tree reference counting to the 4.8-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: net-dsa-fix-unbalanced-dsa_switch_tree-reference-counting.patch and it can be found in the queue-4.8 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >>From foo@baz Thu Dec 8 07:19:12 CET 2016 From: Nikita Yushchenko Date: Mon, 28 Nov 2016 09:48:48 +0300 Subject: net: dsa: fix unbalanced dsa_switch_tree reference counting From: Nikita Yushchenko [ Upstream commit 7a99cd6e213685b78118382e6a8fed506c82ccb2 ] _dsa_register_switch() gets a dsa_switch_tree object either via dsa_get_dst() or via dsa_add_dst(). Former path does not increase kref in returned object (resulting into caller not owning a reference), while later path does create a new object (resulting into caller owning a reference). The rest of _dsa_register_switch() assumes that it owns a reference, and calls dsa_put_dst(). This causes a memory breakage if first switch in the tree initialized successfully, but second failed to initialize. In particular, freed dsa_swith_tree object is left referenced by switch that was initialized, and later access to sysfs attributes of that switch cause OOPS. To fix, need to add kref_get() call to dsa_get_dst(). Fixes: 83c0afaec7b7 ("net: dsa: Add new binding implementation") Signed-off-by: Nikita Yushchenko Reviewed-by: Andrew Lunn Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/dsa/dsa2.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) --- a/net/dsa/dsa2.c +++ b/net/dsa/dsa2.c @@ -28,8 +28,10 @@ static struct dsa_switch_tree *dsa_get_d struct dsa_switch_tree *dst; list_for_each_entry(dst, &dsa_switch_trees, list) - if (dst->tree == tree) + if (dst->tree == tree) { + kref_get(&dst->refcount); return dst; + } return NULL; } Patches currently in stable-queue which might be from nikita.yoush@cogentembedded.com are queue-4.8/net-dsa-fix-unbalanced-dsa_switch_tree-reference-counting.patch