[+cc linux-pci, Myron, Joe] On Wed, Jun 12, 2013 at 11:21 AM, Radim Krčmář <rkrcmar@xxxxxxxxxx> wrote: > Hello, > > as a consequence of hitting a NULL dereference bug[1] while downstream > aspm is setting up link_state, I started to wonder why is the code > skipping its parent bus in favour of grandparent's link_state.[2] > > Is this right? (I have no device to test on ...) > > Thanks. > > --- > 1: https://bugzilla.redhat.com/show_bug.cgi?id=972381 > The bug is hit because "pdev->bus->parent" has NULL "->parent" and thus > NULL "->self". > 2: "pdev = bus->self", so "pdev->bus->parent == bus->parent->parent" > > > diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c > index 403a443..d58e282 100644 > --- a/drivers/pci/pcie/aspm.c > +++ b/drivers/pci/pcie/aspm.c > @@ -527,7 +527,7 @@ static struct pcie_link_state *alloc_pcie_link_state(struct pci_dev *pdev) > link->pdev = pdev; > if (pci_pcie_type(pdev) == PCI_EXP_TYPE_DOWNSTREAM) { > struct pcie_link_state *parent; > - parent = pdev->bus->parent->self->link_state; > + parent = pdev->bus->self->link_state; > if (!parent) { > kfree(link); > return NULL; > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
