From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751173AbdJYMCS (ORCPT ); Wed, 25 Oct 2017 08:02:18 -0400 Received: from lelnx194.ext.ti.com ([198.47.27.80]:19496 "EHLO lelnx194.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750798AbdJYMCQ (ORCPT ); Wed, 25 Oct 2017 08:02:16 -0400 Subject: Re: [PATCH] PCI: endpoint: handle probable NULL pointer access To: Bjorn Helgaas , Pankaj Dubey References: <1507780677-7983-1-git-send-email-pankaj.dubey@samsung.com> <20171024200200.GE21840@bhelgaas-glaptop.roam.corp.google.com> CC: , , Bjorn Helgaas From: Kishon Vijay Abraham I Message-ID: <6ee65418-8589-01c1-2156-67fbf881260a@ti.com> Date: Wed, 25 Oct 2017 17:32:07 +0530 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.7.0 MIME-Version: 1.0 In-Reply-To: <20171024200200.GE21840@bhelgaas-glaptop.roam.corp.google.com> Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 7bit X-EXCLAIMER-MD-CONFIG: e1e8a2fd-e40a-4ac6-ac9b-f7e9cc9ee180 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, On Wednesday 25 October 2017 01:32 AM, Bjorn Helgaas wrote: > On Thu, Oct 12, 2017 at 09:27:57AM +0530, Pankaj Dubey wrote: >> controller_group allocation in pci_ep_cfs_init function can fail >> so we should have a check while using it in pci_ep_cfs_add_epc_group >> for registering group, else we will hit NULL pointer access. >> >> This patch adds required check for the same and returns -EPROBE_DEFER, >> so that endpoint controller driver probe can be reattempted later >> in case controller_group is not allocated because pci_ep_cfs_init is >> not yet called. >> >> Signed-off-by: Pankaj Dubey > > Looking for Kishon's ack here. > >> --- >> drivers/pci/endpoint/pci-ep-cfs.c | 7 ++++++- >> drivers/pci/endpoint/pci-epc-core.c | 4 ++++ >> 2 files changed, 10 insertions(+), 1 deletion(-) >> >> diff --git a/drivers/pci/endpoint/pci-ep-cfs.c b/drivers/pci/endpoint/pci-ep-cfs.c >> index 424fdd6..3cac818 100644 >> --- a/drivers/pci/endpoint/pci-ep-cfs.c >> +++ b/drivers/pci/endpoint/pci-ep-cfs.c >> @@ -172,7 +172,12 @@ struct config_group *pci_ep_cfs_add_epc_group(const char *name) >> group = &epc_group->group; >> >> config_group_init_type_name(group, name, &pci_epc_type); >> - ret = configfs_register_group(controllers_group, group); >> + >> + if (controllers_group) >> + ret = configfs_register_group(controllers_group, group); >> + else >> + ret = -EPROBE_DEFER; >> + Do you ever face this issue? Ideally controllers_group should always be initialized if the dependencies are modeled properly. >> if (ret) { >> pr_err("failed to register configfs group for %s\n", name); >> goto err_register_group; >> diff --git a/drivers/pci/endpoint/pci-epc-core.c b/drivers/pci/endpoint/pci-epc-core.c >> index 42c2a11..d327a2a 100644 >> --- a/drivers/pci/endpoint/pci-epc-core.c >> +++ b/drivers/pci/endpoint/pci-epc-core.c >> @@ -518,6 +518,10 @@ __pci_epc_create(struct device *dev, const struct pci_epc_ops *ops, >> goto put_dev; >> >> epc->group = pci_ep_cfs_add_epc_group(dev_name(dev)); >> + if (IS_ERR(epc->group)) { >> + ret = -EPROBE_DEFER; should use the return value of pci_ep_cfs_add_epc_group(). However I don't think this is required since drivers might not actually need cfs. Thanks Kishon