From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4412A38C423; Mon, 12 Oct 2026 22:18:45 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791843526; cv=none; b=B+G8+u9waSRARyOqDTKWyebuQm2cGQc0WLxLIDh/pUXbWJwzuKSeZ/7HhNblJrImrXBR968DwxTg79CWd5qT++1NWz/mMRuEeX2ml1v8w+rk9l6c3r6SyVmUQ10xwI/nUAkh/uJpcwk183e2LAcQXry71bOizHOkhH0qAhPYGjU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791843526; c=relaxed/simple; bh=6q1dtZ4mFmGnR51E/lgbvW0mQS6LBiXKQ/GO0QIZaYE=; h=Date:From:To:Cc:Subject:Message-ID:MIME-Version:Content-Type: Content-Disposition:In-Reply-To; b=bX0l3WjkLUmKHrlhwxgBy7lFAeS/31SFV3Ub20F1jjmA2tcvZsWdR2m8DiGBq/2rMrN22gGXyfIrFsfaBnItjk2wy2xB/UhybKAiVyqojCCy5niZ12NKgha+VjT+99wcSFa7BglIhzxrpXpqzwKC41PVXKpSyFBxIKFeN/ktN3Q= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=WRzyh2Na; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="WRzyh2Na" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9F2381F0089B; Mon, 12 Oct 2026 22:18:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1791843524; bh=SdztuT0CNnTRxqqFV8Jd29fRStGataYciuWQTe88Lno=; h=Date:From:To:Cc:Subject:In-Reply-To; b=WRzyh2NaOnyCk+x5vq84UE/CiaqgreCrQ8DcuAFs/hjqCahoZ4AxVCtVbPKnxbnEi SBXeYwTir5rsEnH8CYXbue+kf8thLFgZNZt0VZqttar8BlzicVrBs5P6se/tdOuAmr LDyvVM5UK63bLnT2Wd1+CybjUfwJD7CPWdD1SEf166OleHqPvLvMbwdM8rZWHa5Rj8 NI3uwFN0mtNGxrp417pLAUBZHKwn2nWh3Ndckz+eX+n+K97yTbdSnLG2nCHxWlrJTd JVh6Y8xoPxJebFf0RufXiLajj9ZPnKdzV1HHVvqPjugiLuy2nFyfmUZ2KmzAt2+m+C v4a8yj+vUCr5Q== Date: Mon, 12 Oct 2026 17:18:43 -0500 From: Bjorn Helgaas To: Herve Codina Cc: Richard Cheng , Andrew Lunn , Rob Herring , Saravana Kannan , Greg Kroah-Hartman , "Rafael J. Wysocki" , Danilo Krummrich , Bjorn Helgaas , Charles Keepax , Richard Fitzgerald , David Rhodes , Linus Walleij , Andy Shevchenko , Daniel Scally , Heikki Krogerus , Sakari Ailus , Bartosz Golaszewski , Len Brown , Davidlohr Bueso , Jonathan Cameron , Dave Jiang , Alison Schofield , Vishal Verma , Dan Williams , Ira Weiny , Li Ming , Lizhi Hou , driver-core@lists.linux.dev, linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, linux-sound@vger.kernel.org, patches@opensource.cirrus.com, linux-gpio@vger.kernel.org, linux-acpi@vger.kernel.org, linux-cxl@vger.kernel.org, Allan Nielsen , Horatiu Vultur , Daniel Machon , Steen Hegelund , Luca Ceresoli , Thomas Petazzoni , stable+noautosel@kernel.org Subject: Re: [PATCH v13 10/10] PCI: of: Avoid np->data usage for the node changeset Message-ID: <20261012221843.GA1409528@bhelgaas> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20261012142826.159178-11-herve.codina@bootlin.com> On Mon, Oct 12, 2026 at 04:28:24PM +0200, Herve Codina wrote: > of_pci_remove_node() and of_pci_remove_host_bridge_node() check > whether the node is dynamic but not whether it has valid private data. > > During the node creation, an OF changeset is used and this changeset is > stored in np->data to be available for removal functions. > > If, for instance, a PCI host bridge is created using a device-tree > overlay, the related node will have the dynamic flag set but np->data > will be NULL. This leads to NULL pointer dereferences. > > Checking for a non-NULL np->data pointer to determine if the node has > been created by the PCI node creation process is not enough. Indeed, > on some platforms like PowerPC, the OF_RECONFIG_ATTACH_NODE notifier > (e.g., in the pci_dn_reconfig_notifier() function) intercepts node > additions and populates np->data with its own structure, such as a > struct pci_dn. In that case, np->data is not NULL but it is not related > to our changeset stored during the PCI node process creation. > > Avoid the usage of np->data to store the changeset used during the PCI > node creation. Store our changeset in a more relevant structure: either > struct pci_dev when the node is created for a PCI device or struct > pci_host_bridge when the node is created for the PCI host bridge. > > With that done, no ambiguity remains on removal. Indeed, this changeset, > if non-NULL, is the one used during PCI node creation. Check and use > this changeset on the removal process. > > Fixes: 407d1a51921e ("PCI: Create device tree node for bridge") > Fixes: 1f340724419e ("PCI: of: Create device tree PCI host bridge node") > Cc: # Issue not triggered but could be a problem > Signed-off-by: Herve Codina Acked-by: Bjorn Helgaas > --- > drivers/pci/of.c | 32 ++++++++++++++++++++------------ > include/linux/pci.h | 11 +++++++++++ > 2 files changed, 31 insertions(+), 12 deletions(-) > > diff --git a/drivers/pci/of.c b/drivers/pci/of.c > index 0a5797652e18..fbed24a244d0 100644 > --- a/drivers/pci/of.c > +++ b/drivers/pci/of.c > @@ -732,15 +732,20 @@ void of_pci_remove_node(struct pci_dev *pdev) > { > struct device_node *np; > > + if (!pdev->cset) > + return; > + > np = pci_device_to_OF_node(pdev); > - if (!np || !of_node_check_flag(np, OF_DYNAMIC)) > + if (!np) > return; > > fw_devlink_set_device(&np->fwnode, NULL); > device_remove_of_node(&pdev->dev); > - of_changeset_revert(np->data); > - of_changeset_destroy(np->data); > + of_changeset_revert(pdev->cset); > + of_changeset_destroy(pdev->cset); > of_node_put(np); > + kfree(pdev->cset); > + pdev->cset = NULL; > } > > void of_pci_make_dev_node(struct pci_dev *pdev) > @@ -800,18 +805,17 @@ void of_pci_make_dev_node(struct pci_dev *pdev) > if (ret) > goto out_clear_devlink_dev; > > - np->data = cset; > - > ret = device_add_of_node(&pdev->dev, np); > if (ret) > goto out_revert_cset; > > + pdev->cset = cset; > + > kfree(name); > > return; > > out_revert_cset: > - np->data = NULL; > of_changeset_revert(cset); > out_clear_devlink_dev: > fw_devlink_set_device(&np->fwnode, NULL); > @@ -828,16 +832,21 @@ void of_pci_remove_host_bridge_node(struct pci_host_bridge *bridge) > { > struct device_node *np; > > + if (!bridge->cset) > + return; > + > np = pci_bus_to_OF_node(bridge->bus); > - if (!np || !of_node_check_flag(np, OF_DYNAMIC)) > + if (!np) > return; > > fw_devlink_set_device(&np->fwnode, NULL); > device_remove_of_node(&bridge->bus->dev); > device_remove_of_node(&bridge->dev); > - of_changeset_revert(np->data); > - of_changeset_destroy(np->data); > + of_changeset_revert(bridge->cset); > + of_changeset_destroy(bridge->cset); > of_node_put(np); > + kfree(bridge->cset); > + bridge->cset = NULL; > } > > void of_pci_make_host_bridge_node(struct pci_host_bridge *bridge) > @@ -899,8 +908,6 @@ void of_pci_make_host_bridge_node(struct pci_host_bridge *bridge) > if (ret) > goto out_clear_devlink_dev; > > - np->data = cset; > - > /* Add the of_node to host bridge and the root bus */ > ret = device_add_of_node(&bridge->dev, np); > if (ret) > @@ -910,6 +917,8 @@ void of_pci_make_host_bridge_node(struct pci_host_bridge *bridge) > if (ret) > goto out_remove_bridge_dev_of_node; > > + bridge->cset = cset; > + > kfree(name); > > return; > @@ -917,7 +926,6 @@ void of_pci_make_host_bridge_node(struct pci_host_bridge *bridge) > out_remove_bridge_dev_of_node: > device_remove_of_node(&bridge->dev); > out_revert_cset: > - np->data = NULL; > of_changeset_revert(cset); > out_clear_devlink_dev: > fw_devlink_set_device(&np->fwnode, NULL); > diff --git a/include/linux/pci.h b/include/linux/pci.h > index d31a8d107b1e..7b0ba9ec7b5c 100644 > --- a/include/linux/pci.h > +++ b/include/linux/pci.h > @@ -339,6 +339,9 @@ struct pcie_link_state; > struct pci_sriov; > struct pci_p2pdma; > struct rcec_ea; > +#ifdef CONFIG_PCI_DYNAMIC_OF_NODES > +struct of_changeset; > +#endif > > /* struct pci_dev - describes a PCI device > * > @@ -598,6 +601,10 @@ struct pci_dev { > u8 tph_mode; /* TPH mode */ > u8 tph_req_type; /* TPH requester type */ > #endif > + > +#ifdef CONFIG_PCI_DYNAMIC_OF_NODES > + struct of_changeset *cset; /* Changeset used for OF node creation */ > +#endif > }; > > static inline struct pci_dev *pci_physfn(struct pci_dev *dev) > @@ -670,6 +677,10 @@ struct pci_host_bridge { > unsigned int broken_l1ss_resume:1; /* Resuming from L1SS during > system suspend is broken */ > > +#ifdef CONFIG_PCI_DYNAMIC_OF_NODES > + struct of_changeset *cset; /* Changeset used for OF node creation */ > +#endif > + > /* Resource alignment requirements */ > resource_size_t (*align_resource)(struct pci_dev *dev, > const struct resource *res, > -- > 2.55.0 >