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=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS 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 D6FF0C4360F for ; Tue, 26 Mar 2019 13:01:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id AF2D12070B for ; Tue, 26 Mar 2019 13:01:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731489AbfCZNBO (ORCPT ); Tue, 26 Mar 2019 09:01:14 -0400 Received: from usa-sjc-mx-foss1.foss.arm.com ([217.140.101.70]:35996 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726177AbfCZNBO (ORCPT ); Tue, 26 Mar 2019 09:01:14 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 6D6A11596; Tue, 26 Mar 2019 06:01:13 -0700 (PDT) Received: from [10.1.196.75] (e110467-lin.cambridge.arm.com [10.1.196.75]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 0B4693F59C; Tue, 26 Mar 2019 06:01:11 -0700 (PDT) Subject: Re: [PATCH v2] pci: pcie-xilinx: fix a missing-check bug for __get_free_pages To: Aditya Pakki Cc: Lorenzo Pieralisi , linux-pci@vger.kernel.org, kjlu@umn.edu, Michal Simek , linux-kernel@vger.kernel.org, Bjorn Helgaas , linux-arm-kernel@lists.infradead.org References: <20190323210423.8881-1-pakki001@umn.edu> From: Robin Murphy Message-ID: Date: Tue, 26 Mar 2019 13:01:10 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.5.1 MIME-Version: 1.0 In-Reply-To: <20190323210423.8881-1-pakki001@umn.edu> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-GB Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 23/03/2019 21:04, Aditya Pakki wrote: > In case __get_free_pages fail, the fix returns error upstream > to avoid NULL pointer dereference. Where does msi_pages ever get dereferenced? The logic here might actually still have a chance of working out OK with NULL depending on how the memory maps line up, but even if it doesn't, the problem is certainly not one of dereferencing. Robin. > Signed-off-by: Aditya Pakki > > --- > v1: Return error upstream as suggested by Steven > --- > drivers/pci/controller/pcie-xilinx.c | 11 +++++++++-- > 1 file changed, 9 insertions(+), 2 deletions(-) > > diff --git a/drivers/pci/controller/pcie-xilinx.c b/drivers/pci/controller/pcie-xilinx.c > index 9bd1a35cd5d8..91d8945bfb0c 100644 > --- a/drivers/pci/controller/pcie-xilinx.c > +++ b/drivers/pci/controller/pcie-xilinx.c > @@ -335,15 +335,19 @@ static const struct irq_domain_ops msi_domain_ops = { > /** > * xilinx_pcie_enable_msi - Enable MSI support > * @port: PCIe port information > + * Return: 0 on success, negative error on failure > */ > -static void xilinx_pcie_enable_msi(struct xilinx_pcie_port *port) > +static int xilinx_pcie_enable_msi(struct xilinx_pcie_port *port) > { > phys_addr_t msg_addr; > > port->msi_pages = __get_free_pages(GFP_KERNEL, 0); > + if (!port->msi_pages) > + return -ENOMEM; > msg_addr = virt_to_phys((void *)port->msi_pages); > pcie_write(port, 0x0, XILINX_PCIE_REG_MSIBASE1); > pcie_write(port, msg_addr, XILINX_PCIE_REG_MSIBASE2); > + return 0; > } > > /* INTx Functions */ > @@ -498,6 +502,7 @@ static int xilinx_pcie_init_irq_domain(struct xilinx_pcie_port *port) > struct device *dev = port->dev; > struct device_node *node = dev->of_node; > struct device_node *pcie_intc_node; > + int ret; > > /* Setup INTx */ > pcie_intc_node = of_get_next_child(node, NULL); > @@ -526,7 +531,9 @@ static int xilinx_pcie_init_irq_domain(struct xilinx_pcie_port *port) > return -ENODEV; > } > > - xilinx_pcie_enable_msi(port); > + ret = xilinx_pcie_enable_msi(port); > + if (ret) > + return ret; > } > > return 0; >