From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753692AbdGJOz6 (ORCPT ); Mon, 10 Jul 2017 10:55:58 -0400 Received: from mail.kernel.org ([198.145.29.99]:40658 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752509AbdGJOz5 (ORCPT ); Mon, 10 Jul 2017 10:55:57 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 67FF122B57 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=helgaas@kernel.org Date: Mon, 10 Jul 2017 09:55:53 -0500 From: Bjorn Helgaas To: Lorenzo Pieralisi Cc: linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, Ralf Baechle , Paul Burton , Bjorn Helgaas Subject: Re: [PATCH 2/2] MIPS/PCI: Fix pcibios_scan_bus() NULL check code path Message-ID: <20170710145553.GA20365@bhelgaas-glaptop.roam.corp.google.com> References: <20170710123409.9043-1-lorenzo.pieralisi@arm.com> <20170710123409.9043-2-lorenzo.pieralisi@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170710123409.9043-2-lorenzo.pieralisi@arm.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jul 10, 2017 at 01:34:09PM +0100, Lorenzo Pieralisi wrote: > If pci_scan_root_bus() fails (ie returns NULL) pcibios_scan_bus() must > return immediately since the struct pci_bus pointer it returns is not > valid and cannot be used. > > Move code checking the pci_scan_root_bus() return value to reinstate > proper pcibios_scanbus() error path behaviour. > > Signed-off-by: Lorenzo Pieralisi > Cc: Ralf Baechle > Cc: Paul Burton > Cc: Bjorn Helgaas I agree this is certainly broken. In fact, I think I broke it with 9e808eb6a768 ("PCI: Cleanup control flow") in 2015. So probably v4.14 material? > --- > arch/mips/pci/pci-legacy.c | 10 +++++----- > 1 file changed, 5 insertions(+), 5 deletions(-) > > diff --git a/arch/mips/pci/pci-legacy.c b/arch/mips/pci/pci-legacy.c > index 174575a..71d62f8 100644 > --- a/arch/mips/pci/pci-legacy.c > +++ b/arch/mips/pci/pci-legacy.c > @@ -89,16 +89,16 @@ static void pcibios_scanbus(struct pci_controller *hose) > pci_add_resource(&resources, hose->busn_resource); > bus = pci_scan_root_bus(NULL, next_busno, hose->pci_ops, hose, > &resources); > - hose->bus = bus; > - > - need_domain_info = need_domain_info || pci_domain_nr(bus); > - set_pci_need_domain_info(hose, need_domain_info); > - > if (!bus) { > pci_free_resource_list(&resources); > return; > } > > + hose->bus = bus; > + > + need_domain_info = need_domain_info || pci_domain_nr(bus); > + set_pci_need_domain_info(hose, need_domain_info); > + > next_busno = bus->busn_res.end + 1; > /* Don't allow 8-bit bus number overflow inside the hose - > reserve some space for bridges. */ > -- > 2.10.0 >