From patchwork Mon Nov 28 06:48:48 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Nikita Yushchenko X-Patchwork-Id: 699869 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 3tRy2v543Sz9tkH for ; Mon, 28 Nov 2016 17:49:27 +1100 (AEDT) Authentication-Results: ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=cogentembedded-com.20150623.gappssmtp.com header.i=@cogentembedded-com.20150623.gappssmtp.com header.b="SNjJiNgv"; dkim-atps=neutral Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754242AbcK1GtP (ORCPT ); Mon, 28 Nov 2016 01:49:15 -0500 Received: from mail-lf0-f51.google.com ([209.85.215.51]:33856 "EHLO mail-lf0-f51.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754075AbcK1GtN (ORCPT ); Mon, 28 Nov 2016 01:49:13 -0500 Received: by mail-lf0-f51.google.com with SMTP id o141so88701941lff.1 for ; Sun, 27 Nov 2016 22:49:13 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=cogentembedded-com.20150623.gappssmtp.com; s=20150623; h=from:to:cc:subject:date:message-id; bh=3Za7C4widMvHvMqEu8u9VMyogNUeUTzyRv46trLw+QU=; b=SNjJiNgv2WQIDwMfwVL7f0/01ca7O5GVUw1Qe6rm7zfeBNN2lPpvvIkgNtfzYgGh6F GGB+h4mAMBKdQ2JDz57WSty/eb1D/NoielctHQ7YkXnOmVdX4MDBWBG+9qN4IQkJt/r8 0F02Xso719RXAJ5nbicww6WnfDoD+YnDwAKUXoPhHljBOl4XHt59qoIzpiS6wxIc5AO9 BvoYfGSG7EOMr4tUBldLxVG86JfqPxQUFFjitOLACMwuu1ystRSUrS1CcBixqCK4BVYd 4iep7ZNdLxc+j8oVqqScDQf3aC1mhf52CeiKTc9GpG0WIkAq+BNgybkNYTK/+Qt01Jwb q49g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:from:to:cc:subject:date:message-id; bh=3Za7C4widMvHvMqEu8u9VMyogNUeUTzyRv46trLw+QU=; b=kBiK9NtztmiepFG9zHl2f1+aIWmodJIxcPc8EbARHJm4YFs0xylAPTLALv77ajaumw DbCOkHP6GAHhlZRVOCI1n+wU/DIFfJW2I1OaOrgYqd6tftuCOX8iKyX+wAsXCqVLRxoV EoZ/QAAFlgYs+FMG5MAx1kmUBUJUvsNj2dyTJgGO4TE4uM8v5TpI65418UWo72FsPbL1 tMZQTxbIVJ/NHp1KUn2aIFck/JurX8Cq+3JJtcniI9dtcdhQbGLl7wUtnH15fglu0xsi hK8ddSeo1yJRchZ9eGeP4J4w1W6UF8oBRVktAprjLDtPbMj30RQn+oieBhqJ3DxLWh7+ xHdw== X-Gm-Message-State: AKaTC0120E1n1UkFuGZ/iD54suQ3AF8+cO5h7zp2MvbiL2RmdIvE0m3mCkqnA2a/aihi0A== X-Received: by 10.46.71.76 with SMTP id u73mr9838330lja.6.1480315752205; Sun, 27 Nov 2016 22:49:12 -0800 (PST) Received: from hugenb.home (nikaet.starlink.ru. [94.141.168.29]) by smtp.gmail.com with ESMTPSA id 5sm12532784ljf.18.2016.11.27.22.49.10 (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Sun, 27 Nov 2016 22:49:11 -0800 (PST) From: Nikita Yushchenko To: "David S. Miller" , netdev@vger.kernel.org Cc: Chris Healy , Andrew Lunn , linux-kernel@vger.kernel.org, Nikita Yushchenko Subject: [patch net] net: dsa: fix unbalanced dsa_switch_tree reference counting Date: Mon, 28 Nov 2016 09:48:48 +0300 Message-Id: <1480315728-23398-1-git-send-email-nikita.yoush@cogentembedded.com> X-Mailer: git-send-email 2.1.4 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org _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(). Signed-off-by: Nikita Yushchenko Fixes: 83c0afaec7b7 ("net: dsa: Add new binding implementation") Reviewed-by: Andrew Lunn --- net/dsa/dsa2.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/net/dsa/dsa2.c b/net/dsa/dsa2.c index f8a7d9aab437..5fff951a0a49 100644 --- a/net/dsa/dsa2.c +++ b/net/dsa/dsa2.c @@ -28,8 +28,10 @@ static struct dsa_switch_tree *dsa_get_dst(u32 tree) 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; }