From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:60354 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753745AbdBDJRK (ORCPT ); Sat, 4 Feb 2017 04:17:10 -0500 Subject: Patch "PCI/ASPM: Handle PCI-to-PCIe bridges as roots of PCIe hierarchies" has been added to the 4.9-stable tree To: bhelgaas@google.com, gregkh@linuxfoundation.org, jnair@caviumnetworks.com Cc: , From: Date: Sat, 04 Feb 2017 10:16:50 +0100 Message-ID: <148619981018111@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 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/ASPM: Handle PCI-to-PCIe bridges as roots of PCIe hierarchies to the 4.9-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-aspm-handle-pci-to-pcie-bridges-as-roots-of-pcie-hierarchies.patch and it can be found in the queue-4.9 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >>From 030305d69fc6963c16003f50d7e8d74b02d0a143 Mon Sep 17 00:00:00 2001 From: Bjorn Helgaas Date: Fri, 27 Jan 2017 15:00:45 -0600 Subject: PCI/ASPM: Handle PCI-to-PCIe bridges as roots of PCIe hierarchies From: Bjorn Helgaas commit 030305d69fc6963c16003f50d7e8d74b02d0a143 upstream. In a struct pcie_link_state, link->root points to the pcie_link_state of the root of the PCIe hierarchy. For the topmost link, this points to itself (link->root = link). For others, we copy the pointer from the parent (link->root = link->parent->root). Previously we recognized that Root Ports originated PCIe hierarchies, but we treated PCI/PCI-X to PCIe Bridges as being in the middle of the hierarchy, and when we tried to copy the pointer from link->parent->root, there was no parent, and we dereferenced a NULL pointer: BUG: unable to handle kernel NULL pointer dereference at 0000000000000090 IP: [] pcie_aspm_init_link_state+0x170/0x820 Recognize that PCI/PCI-X to PCIe Bridges originate PCIe hierarchies just like Root Ports do, so link->root for these devices should also point to itself. Fixes: 51ebfc92b72b ("PCI: Enumerate switches below PCI-to-PCIe bridges") Link: https://bugzilla.kernel.org/show_bug.cgi?id=193411 Link: https://bugzilla.opensuse.org/show_bug.cgi?id=1022181 Tested-by: lists@ssl-mail.com Tested-by: Jayachandran C. Signed-off-by: Bjorn Helgaas Signed-off-by: Greg Kroah-Hartman --- drivers/pci/pcie/aspm.c | 19 +++++++++++++------ 1 file changed, 13 insertions(+), 6 deletions(-) --- a/drivers/pci/pcie/aspm.c +++ b/drivers/pci/pcie/aspm.c @@ -518,25 +518,32 @@ static struct pcie_link_state *alloc_pci link = kzalloc(sizeof(*link), GFP_KERNEL); if (!link) return NULL; + INIT_LIST_HEAD(&link->sibling); INIT_LIST_HEAD(&link->children); INIT_LIST_HEAD(&link->link); link->pdev = pdev; - if (pci_pcie_type(pdev) != PCI_EXP_TYPE_ROOT_PORT) { + + /* + * Root Ports and PCI/PCI-X to PCIe Bridges are roots of PCIe + * hierarchies. + */ + if (pci_pcie_type(pdev) == PCI_EXP_TYPE_ROOT_PORT || + pci_pcie_type(pdev) == PCI_EXP_TYPE_PCIE_BRIDGE) { + link->root = link; + } else { struct pcie_link_state *parent; + parent = pdev->bus->parent->self->link_state; if (!parent) { kfree(link); return NULL; } + link->parent = parent; + link->root = link->parent->root; list_add(&link->link, &parent->children); } - /* Setup a pointer to the root port link */ - if (!link->parent) - link->root = link; - else - link->root = link->parent->root; list_add(&link->sibling, &link_list); pdev->link_state = link; Patches currently in stable-queue which might be from bhelgaas@google.com are queue-4.9/pci-aspm-handle-pci-to-pcie-bridges-as-roots-of-pcie-hierarchies.patch