From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752713AbcKAQsv (ORCPT ); Tue, 1 Nov 2016 12:48:51 -0400 Received: from shards.monkeyblade.net ([184.105.139.130]:48094 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751592AbcKAQsu (ORCPT ); Tue, 1 Nov 2016 12:48:50 -0400 Date: Tue, 01 Nov 2016 12:48:48 -0400 (EDT) Message-Id: <20161101.124848.1812844488411463169.davem@davemloft.net> To: johan@kernel.org Cc: f.fainelli@gmail.com, mugunthanvnm@ti.com, yisen.zhuang@huawei.com, salil.mehta@huawei.com, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH net 2/4] net: ethernet: ti: cpsw: fix device and of_node leaks From: David Miller In-Reply-To: <20161101164225.GC2664@localhost> References: <1477998217-30143-3-git-send-email-johan@kernel.org> <20161101.122711.1685573538225505004.davem@davemloft.net> <20161101164225.GC2664@localhost> X-Mailer: Mew version 6.7 on Emacs 24.5 / Mule 6.0 (HANACHIRUSATO) Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.5.12 (shards.monkeyblade.net [149.20.54.216]); Tue, 01 Nov 2016 08:49:16 -0700 (PDT) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Johan Hovold Date: Tue, 1 Nov 2016 17:42:25 +0100 > On Tue, Nov 01, 2016 at 12:27:11PM -0400, David Miller wrote: >> From: Johan Hovold >> Date: Tue, 1 Nov 2016 12:03:35 +0100 >> >> > diff --git a/drivers/net/ethernet/ti/cpsw-phy-sel.c b/drivers/net/ethernet/ti/cpsw-phy-sel.c >> > index 054a8dd23dae..589beb843f56 100644 >> > --- a/drivers/net/ethernet/ti/cpsw-phy-sel.c >> > +++ b/drivers/net/ethernet/ti/cpsw-phy-sel.c >> > @@ -176,8 +176,11 @@ void cpsw_phy_sel(struct device *dev, phy_interface_t phy_mode, int slave) >> > } >> > >> > dev = bus_find_device(&platform_bus_type, NULL, node, match); >> > + of_node_put(node); >> > priv = dev_get_drvdata(dev); >> > >> > + put_device(dev); >> > + >> > priv->cpsw_phy_sel(priv, phy_mode, slave); >> > } >> > EXPORT_SYMBOL_GPL(cpsw_phy_sel); >> >> The only reference you have to 'dev' is the one obtained from the >> bus_find_device() call, therefore you must at least hold onto >> 'dev' until after the priv->cpsw_phy_sel(priv, phy_mode, slave); call. > > As I mentioned in the commit message "...there is no guarantee that the > devres-managed struct cpsw_phy_sel_priv will continue to be valid until > this function returns regardless of this change". > > Specifically, holding a reference to dev does not prevent the > cpsw_phy_sel driver from being unbound and priv from being freed. But you should at least hold onto the object while you call a function pointer embedded in a data structure referred by it.