diff options
authorBjorn Helgaas <bhelgaas@google.com>2017-01-27 15:00:45 -0600
committerBjorn Helgaas <bhelgaas@google.com>2017-01-27 15:00:45 -0600
commit030305d69fc6963c16003f50d7e8d74b02d0a143 (patch)
parent4d191b1b63c209e37bf27938ef365244d3c41084 (diff)
PCI/ASPM: Handle PCI-to-PCIe bridges as roots of PCIe hierarchies
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: [<ffffffff9e424350>] 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. <jnair@caviumnetworks.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> CC: stable@vger.kernel.org # v4.2+
1 files changed, 13 insertions, 6 deletions
diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c
index 17ac1dce3286..3dd8bcbb3011 100644
--- a/drivers/pci/pcie/aspm.c
+++ b/drivers/pci/pcie/aspm.c
@@ -532,25 +532,32 @@ static struct pcie_link_state *alloc_pcie_link_state(struct pci_dev *pdev)
link = kzalloc(sizeof(*link), GFP_KERNEL);
if (!link)
return NULL;
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) {
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;