Fix pointer dereference before call to pcie_bus_configure_settings (5307f6d5) · Commits · 戴 / test

Commit ("PCI: Set PCI-E Max Payload Size on fabric") introduced a potential NULL pointer dereference in calls to pcie_bus_configure_settings due to attempts to access pci_bus self variables when the self pointer is NULL. To correct this, verify that the self pointer in pci_bus is non-NULL before dereferencing it. Reported-by:

Stanislaw Gruszka <sgruszka@redhat.com> Signed-off-by:

Shyam Iyer <shyam_iyer@dell.com> Signed-off-by:

Jon Mason <mason@myri.com> Acked-by:

Jesse Barnes <jbarnes@virtuousgeek.org> Signed-off-by:

Linus Torvalds <torvalds@linux-foundation.org>

arch/x86/pci/acpi.c

+7 −2

Original line number	Diff line number	Diff line
		@@ -365,8 +365,13 @@ struct pci_bus * __devinit pci_acpi_scan_root(struct acpi_pci_root *root)
		*/
		if (bus) {
		struct pci_bus *child;
		list_for_each_entry(child, &bus->children, node)
		pcie_bus_configure_settings(child, child->self->pcie_mpss);
		list_for_each_entry(child, &bus->children, node) {
		struct pci_dev *self = child->self;
		if (!self)
		continue;

		pcie_bus_configure_settings(child, self->pcie_mpss);
		}
		}

		if (!bus)

drivers/pci/hotplug/pcihp_slot.c

+3 −1

Original line number	Diff line number	Diff line
		@@ -169,7 +169,9 @@ void pci_configure_slot(struct pci_dev *dev)
		(dev->class >> 8) == PCI_CLASS_BRIDGE_PCI)))
		return;

		pcie_bus_configure_settings(dev->bus, dev->bus->self->pcie_mpss);
		if (dev->bus && dev->bus->self)
		pcie_bus_configure_settings(dev->bus,
		dev->bus->self->pcie_mpss);

		memset(&hpp, 0, sizeof(hpp));
		ret = pci_get_hp_params(dev, &hpp);

drivers/pci/probe.c

+0 −3

Original line number	Diff line number	Diff line
		@@ -1456,9 +1456,6 @@ void pcie_bus_configure_settings(struct pci_bus *bus, u8 mpss)
		{
		u8 smpss = mpss;

		if (!bus->self)
		return;

		if (!pci_is_pcie(bus->self))
		return;

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