From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: [PATCH net 2/4] net: ethernet: ti: cpsw: fix device and of_node leaks Date: Tue, 01 Nov 2016 12:48:48 -0400 (EDT) Message-ID: <20161101.124848.1812844488411463169.davem@davemloft.net> References: <1477998217-30143-3-git-send-email-johan@kernel.org> <20161101.122711.1685573538225505004.davem@davemloft.net> <20161101164225.GC2664@localhost> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit 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 To: johan@kernel.org Return-path: In-Reply-To: <20161101164225.GC2664@localhost> Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.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.