From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id CDE47C433E1 for ; Mon, 29 Jun 2020 21:54:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A9BAC206C3 for ; Mon, 29 Jun 2020 21:54:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1593467648; bh=8Q9utLRDcnT3OfTmE6oq5FQ33PyN3Sqn6OmCDvz+lGA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=gYlVYpFYLqHsladxoklSu8vSoLd5AF3aWXgMV03fxRuQ0hi37SShDWJVkRVgTnRyZ fgQPcydzOLX8XFBN6oWzg5wCCeqKPvkJOyu42K/s2PCiGVsbt9BQQvMIVT3cTnnOkt XajbnBEqPI25QofLZOzYIjVTp33NdCb13Bj1WWEg= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2404638AbgF2Vxf (ORCPT ); Mon, 29 Jun 2020 17:53:35 -0400 Received: from mail.kernel.org ([198.145.29.99]:56788 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726581AbgF2Sfd (ORCPT ); Mon, 29 Jun 2020 14:35:33 -0400 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 0CFFA2417C; Mon, 29 Jun 2020 15:19:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1593443948; bh=8Q9utLRDcnT3OfTmE6oq5FQ33PyN3Sqn6OmCDvz+lGA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=dIVmGak2VoWWIkFcMX3MCvfMfcUZmzRTAJfklwIWtMxqIF4lL2keJLnMMGlAxMDys JOM9WeQFKeD1iKtK1z4S/cmP3HStY40DJc6EpzRHKvJ6pnSa1XxU82MjLT/xuFmT31 pxqbE4WXJ8zUhrLZJGNWZcIbwCpRbX17X0/1yXjI= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Florian Fainelli , Andrew Lunn , "David S . Miller" , Greg Kroah-Hartman Subject: [PATCH 5.7 050/265] net: dsa: bcm_sf2: Fix node reference count Date: Mon, 29 Jun 2020 11:14:43 -0400 Message-Id: <20200629151818.2493727-51-sashal@kernel.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200629151818.2493727-1-sashal@kernel.org> References: <20200629151818.2493727-1-sashal@kernel.org> MIME-Version: 1.0 X-KernelTest-Patch: http://kernel.org/pub/linux/kernel/v5.x/stable-review/patch-5.7.7-rc1.gz X-KernelTest-Tree: git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git X-KernelTest-Branch: linux-5.7.y X-KernelTest-Patches: git://git.kernel.org/pub/scm/linux/kernel/git/stable/stable-queue.git X-KernelTest-Version: 5.7.7-rc1 X-KernelTest-Deadline: 2020-07-01T15:14+00:00 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Florian Fainelli [ Upstream commit 8dbe4c5d5e40fe140221024f7b16bec9f310bf70 ] of_find_node_by_name() will do an of_node_put() on the "from" argument. With CONFIG_OF_DYNAMIC enabled which checks for device_node reference counts, we would be getting a warning like this: [ 6.347230] refcount_t: increment on 0; use-after-free. [ 6.352498] WARNING: CPU: 3 PID: 77 at lib/refcount.c:156 refcount_inc_checked+0x38/0x44 [ 6.360601] Modules linked in: [ 6.363661] CPU: 3 PID: 77 Comm: kworker/3:1 Tainted: G W 5.4.46-gb78b3e9956e6 #13 [ 6.372546] Hardware name: BCM97278SV (DT) [ 6.376649] Workqueue: events deferred_probe_work_func [ 6.381796] pstate: 60000005 (nZCv daif -PAN -UAO) [ 6.386595] pc : refcount_inc_checked+0x38/0x44 [ 6.391133] lr : refcount_inc_checked+0x38/0x44 ... [ 6.478791] Call trace: [ 6.481243] refcount_inc_checked+0x38/0x44 [ 6.485433] kobject_get+0x3c/0x4c [ 6.488840] of_node_get+0x24/0x34 [ 6.492247] of_irq_find_parent+0x3c/0xe0 [ 6.496263] of_irq_parse_one+0xe4/0x1d0 [ 6.500191] irq_of_parse_and_map+0x44/0x84 [ 6.504381] bcm_sf2_sw_probe+0x22c/0x844 [ 6.508397] platform_drv_probe+0x58/0xa8 [ 6.512413] really_probe+0x238/0x3fc [ 6.516081] driver_probe_device+0x11c/0x12c [ 6.520358] __device_attach_driver+0xa8/0x100 [ 6.524808] bus_for_each_drv+0xb4/0xd0 [ 6.528650] __device_attach+0xd0/0x164 [ 6.532493] device_initial_probe+0x24/0x30 [ 6.536682] bus_probe_device+0x38/0x98 [ 6.540524] deferred_probe_work_func+0xa8/0xd4 [ 6.545061] process_one_work+0x178/0x288 [ 6.549078] process_scheduled_works+0x44/0x48 [ 6.553529] worker_thread+0x218/0x270 [ 6.557285] kthread+0xdc/0xe4 [ 6.560344] ret_from_fork+0x10/0x18 [ 6.563925] ---[ end trace 68f65caf69bb152a ]--- Fix this by adding a of_node_get() to increment the reference count prior to the call. Fixes: afa3b592953b ("net: dsa: bcm_sf2: Ensure correct sub-node is parsed") Signed-off-by: Florian Fainelli Reviewed-by: Andrew Lunn Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- drivers/net/dsa/bcm_sf2.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/net/dsa/bcm_sf2.c b/drivers/net/dsa/bcm_sf2.c index c7ac63f419184..946e41f020a56 100644 --- a/drivers/net/dsa/bcm_sf2.c +++ b/drivers/net/dsa/bcm_sf2.c @@ -1147,6 +1147,8 @@ static int bcm_sf2_sw_probe(struct platform_device *pdev) set_bit(0, priv->cfp.used); set_bit(0, priv->cfp.unique); + /* Balance of_node_put() done by of_find_node_by_name() */ + of_node_get(dn); ports = of_find_node_by_name(dn, "ports"); if (ports) { bcm_sf2_identify_ports(priv, ports); -- 2.25.1