From patchwork Tue Sep 22 16:18:02 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Russell King X-Patchwork-Id: 7240861 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork1.web.kernel.org (Postfix) with ESMTP id 134F29F32B for ; Tue, 22 Sep 2015 16:23:40 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 21365208C3 for ; Tue, 22 Sep 2015 16:23:39 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.9]) (using TLSv1.2 with cipher AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 3A7E0208C4 for ; Tue, 22 Sep 2015 16:23:38 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1ZeQJk-0001Ln-26; Tue, 22 Sep 2015 16:21:20 +0000 Received: from pandora.arm.linux.org.uk ([2001:4d48:ad52:3201:214:fdff:fe10:1be6]) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1ZeQJ5-0006gN-0h for linux-arm-kernel@lists.infradead.org; Tue, 22 Sep 2015 16:20:41 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=arm.linux.org.uk; s=pandora-2014; h=Date:Sender:Message-Id:Content-Type:Content-Transfer-Encoding:MIME-Version:Subject:Cc:To:From:References:In-Reply-To; bh=77PjqOqJm+XfE5yurfiAqUhkMH6b5s0DGdxEarXXilo=; b=W9PifEh21k3XUalJCgu5OslapGRbP4wqo4Hp0sZ7Uc4RkicqS7VsoRWrLA4UtcdxzQMOA52gF0UuE2fg6N54OR7dMGuUSR4Wp03gmX0mrjX/Xt3cVfysjh3dymMMPZ2EoGMN3jDWDGJQM8j0HqmRtIeTzBMdKXCMXUjhLTQzwBI=; Received: from e0022681537dd.dyn.arm.linux.org.uk ([fd8f:7570:feb6:1:222:68ff:fe15:37dd]:54465 helo=rmk-PC.arm.linux.org.uk) by pandora.arm.linux.org.uk with esmtpsa (TLSv1:AES128-SHA:128) (Exim 4.82_1-5b7a7c0-XX) (envelope-from ) id 1ZeQGa-0000Qv-LH; Tue, 22 Sep 2015 17:18:04 +0100 Received: from rmk by rmk-PC.arm.linux.org.uk with local (Exim 4.82_1-5b7a7c0-XX) (envelope-from ) id 1ZeQGY-0006UR-Mo; Tue, 22 Sep 2015 17:18:02 +0100 In-Reply-To: <20150922161710.GA21084@n2100.arm.linux.org.uk> References: <20150922161710.GA21084@n2100.arm.linux.org.uk> From: Russell King To: Florian Fainelli , David Miller Subject: [PATCH 1/9] phy: fix of_mdio_find_bus() device refcount leak MIME-Version: 1.0 Content-Disposition: inline Message-Id: Date: Tue, 22 Sep 2015 17:18:02 +0100 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20150922_092039_536216_9B24D810 X-CRM114-Status: GOOD ( 15.51 ) X-Spam-Score: -2.7 (--) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Thomas Petazzoni , devicetree@vger.kernel.org, Sunil Goutham , Robert Richter , Frank Rowand , linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, Rob Herring , Michal Simek , netdev@vger.kernel.org, Soren Brinkmann , Iyappan Subramanian , Grant Likely , Li Yang , Keyur Chudgar , linux-arm-kernel@lists.infradead.org Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Spam-Status: No, score=-4.1 required=5.0 tests=BAYES_00,DKIM_SIGNED, RCVD_IN_DNSWL_MED,RP_MATCHES_RCVD,T_DKIM_INVALID,UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP of_mdio_find_bus() leaks a struct device refcount, caused by using class_find_device() and not realising that the device reference has its refcount incremented: * Note, you will need to drop the reference with put_device() after use. ... while ((dev = class_dev_iter_next(&iter))) { if (match(dev, data)) { get_device(dev); break; } Update the comment, and arrange for the phy code to drop this refcount when disposing of a reference to it. Signed-off-by: Russell King --- drivers/net/phy/mdio-mux.c | 19 +++++++++++++------ drivers/net/phy/mdio_bus.c | 4 +++- 2 files changed, 16 insertions(+), 7 deletions(-) diff --git a/drivers/net/phy/mdio-mux.c b/drivers/net/phy/mdio-mux.c index 4d4d25efc1e1..280c7c311f72 100644 --- a/drivers/net/phy/mdio-mux.c +++ b/drivers/net/phy/mdio-mux.c @@ -113,18 +113,18 @@ int mdio_mux_init(struct device *dev, if (!parent_bus_node) return -ENODEV; - parent_bus = of_mdio_find_bus(parent_bus_node); - if (parent_bus == NULL) { - ret_val = -EPROBE_DEFER; - goto err_parent_bus; - } - pb = devm_kzalloc(dev, sizeof(*pb), GFP_KERNEL); if (pb == NULL) { ret_val = -ENOMEM; goto err_parent_bus; } + parent_bus = of_mdio_find_bus(parent_bus_node); + if (parent_bus == NULL) { + ret_val = -EPROBE_DEFER; + goto err_parent_bus; + } + pb->switch_data = data; pb->switch_fn = switch_fn; pb->current_child = -1; @@ -173,6 +173,10 @@ int mdio_mux_init(struct device *dev, dev_info(dev, "Version " DRV_VERSION "\n"); return 0; } + + /* balance the reference of_mdio_find_bus() took */ + put_device(&pb->mii_bus->dev); + err_parent_bus: of_node_put(parent_bus_node); return ret_val; @@ -189,6 +193,9 @@ void mdio_mux_uninit(void *mux_handle) mdiobus_free(cb->mii_bus); cb = cb->next; } + + /* balance the reference of_mdio_find_bus() in mdio_mux_init() took */ + put_device(&pb->mii_bus->dev); } EXPORT_SYMBOL_GPL(mdio_mux_uninit); diff --git a/drivers/net/phy/mdio_bus.c b/drivers/net/phy/mdio_bus.c index 02a4615b65f8..67553e13bd36 100644 --- a/drivers/net/phy/mdio_bus.c +++ b/drivers/net/phy/mdio_bus.c @@ -167,7 +167,9 @@ static int of_mdio_bus_match(struct device *dev, const void *mdio_bus_np) * of_mdio_find_bus - Given an mii_bus node, find the mii_bus. * @mdio_bus_np: Pointer to the mii_bus. * - * Returns a pointer to the mii_bus, or NULL if none found. + * Returns a reference to the mii_bus, or NULL if none found. The + * embedded struct device will have its reference count incremented, + * and this must be put once the bus is finished with. * * Because the association of a device_node and mii_bus is made via * of_mdiobus_register(), the mii_bus cannot be found before it is