From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:46469 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751195AbcCLHFz (ORCPT ); Sat, 12 Mar 2016 02:05:55 -0500 Subject: Patch "PCI: Allow a NULL "parent" pointer in pci_bus_assign_domain_nr()" has been added to the 4.4-stable tree To: khalasa@piap.pl, bhelgaas@google.com, gregkh@linuxfoundation.org, lorenzo.pieralisi@arm.com Cc: , From: Date: Fri, 11 Mar 2016 23:04:43 -0800 Message-ID: <14577662836558@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: This is a note to let you know that I've just added the patch titled PCI: Allow a NULL "parent" pointer in pci_bus_assign_domain_nr() to the 4.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: pci-allow-a-null-parent-pointer-in-pci_bus_assign_domain_nr.patch and it can be found in the queue-4.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >>From 54c6e2dd00c313d0add58e5befe62fe6f286d03b Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Krzysztof=20=3D=3Futf-8=3FQ=3FHa=3DC5=3D82asa=3F=3D?= Date: Tue, 1 Mar 2016 07:07:18 +0100 Subject: PCI: Allow a NULL "parent" pointer in pci_bus_assign_domain_nr() MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Krzysztof =?utf-8?Q?Ha=C5=82asa?= commit 54c6e2dd00c313d0add58e5befe62fe6f286d03b upstream. pci_create_root_bus() passes a "parent" pointer to pci_bus_assign_domain_nr(). When CONFIG_PCI_DOMAINS_GENERIC is defined, pci_bus_assign_domain_nr() dereferences that pointer. Many callers of pci_create_root_bus() supply a NULL "parent" pointer, which leads to a NULL pointer dereference error. 7c674700098c ("PCI: Move domain assignment from arm64 to generic code") moved the "parent" dereference from arm64 to generic code. Only arm64 used that code (because only arm64 defined CONFIG_PCI_DOMAINS_GENERIC), and it always supplied a valid "parent" pointer. Other arches supplied NULL "parent" pointers but didn't defined CONFIG_PCI_DOMAINS_GENERIC, so they used a no-op version of pci_bus_assign_domain_nr(). 8c7d14746abc ("ARM/PCI: Move to generic PCI domains") defined CONFIG_PCI_DOMAINS_GENERIC on ARM, and many ARM platforms use pci_common_init(), which supplies a NULL "parent" pointer. These platforms (cns3xxx, dove, footbridge, iop13xx, etc.) crash with a NULL pointer dereference like this while probing PCI: Unable to handle kernel NULL pointer dereference at virtual address 000000a4 PC is at pci_bus_assign_domain_nr+0x10/0x84 LR is at pci_create_root_bus+0x48/0x2e4 Kernel panic - not syncing: Attempted to kill init! [bhelgaas: changelog, add "Reported:" and "Fixes:" tags] Reported: http://forum.doozan.com/read.php?2,17868,22070,quote=1 Fixes: 8c7d14746abc ("ARM/PCI: Move to generic PCI domains") Fixes: 7c674700098c ("PCI: Move domain assignment from arm64 to generic code") Signed-off-by: Krzysztof Hałasa Signed-off-by: Bjorn Helgaas Acked-by: Lorenzo Pieralisi Signed-off-by: Greg Kroah-Hartman --- drivers/pci/pci.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -4772,8 +4772,10 @@ int pci_get_new_domain_nr(void) void pci_bus_assign_domain_nr(struct pci_bus *bus, struct device *parent) { static int use_dt_domains = -1; - int domain = of_get_pci_domain_nr(parent->of_node); + int domain = -1; + if (parent) + domain = of_get_pci_domain_nr(parent->of_node); /* * Check DT domain and use_dt_domains values. * Patches currently in stable-queue which might be from khalasa@piap.pl are queue-4.4/pci-allow-a-null-parent-pointer-in-pci_bus_assign_domain_nr.patch