I confirmed this patch fix the kernel oops problem I reported. Reviewed-by: Kenji Kaneshige <kaneshige.kenji@xxxxxxxxxxxxxx> Tested-by: Kenji Kaneshige <kaneshige.kenji@xxxxxxxxxxxxxx> By the way, /sys/bus/pci/slots/<slot> directory by acpiphp are remaining even after the parent bridge/bus of the slots are removed. At this point, acpiphp is working with struct pci_bus for the already disabled pci bus. I guess some operation against the files under /sys/bus/pci/slots/<slot> directory would cause something problems. So I think we also need something mechanism to unregister acpiphp slots when the parent bus is removed. Thanks, Kenji Kaneshige Alex Chiang wrote: > If a logical hot unplug (remove) is performed on a bridge claimed > by acpiphp and then acpiphp is unloaded, we will encounter an oops. > > This is because acpiphp will access the bridge's subordinate bus, > which was released by the user's prior hot unplug. > > The solution is to grab a reference on the subordinate PCI bus. > This will prevent the bus from release until acpiphp is unloaded. > > Reported-by: Kenji Kaneshige <kaneshige.kenji@xxxxxxxxxxxxxx> > Signed-off-by: Alex Chiang <achiang@xxxxxx> > --- > > drivers/pci/hotplug/acpiphp_glue.c | 14 ++++++++++++++ > 1 files changed, 14 insertions(+), 0 deletions(-) > > diff --git a/drivers/pci/hotplug/acpiphp_glue.c b/drivers/pci/hotplug/acpiphp_glue.c > index 803d9dd..a33794d 100644 > --- a/drivers/pci/hotplug/acpiphp_glue.c > +++ b/drivers/pci/hotplug/acpiphp_glue.c > @@ -38,6 +38,8 @@ > * - The one in acpiphp_bridge has its refcount elevated by pci_get_slot() > * when the bridge is scanned and it loses a refcount when the bridge > * is removed. > + * - When a P2P bridge is present, we elevate the refcount on the subordinate > + * bus. It loses the refcount when the the driver unloads. > */ > > #include <linux/init.h> > @@ -440,6 +442,12 @@ static void add_p2p_bridge(acpi_handle *handle, struct pci_dev *pci_dev) > goto err; > } > > + /* > + * Grab a ref to the subordinate PCI bus in case the bus is > + * removed via PCI core logical hotplug. The ref pins the bus > + * (which we access during module unload). > + */ > + get_device(&bridge->pci_bus->dev); > spin_lock_init(&bridge->res_lock); > > init_bridge_misc(bridge); > @@ -619,6 +627,12 @@ static void cleanup_bridge(struct acpiphp_bridge *bridge) > slot = next; > } > > + /* > + * Only P2P bridges have a pci_dev > + */ > + if (bridge->pci_dev) > + put_device(&bridge->pci_bus->dev); > + > pci_dev_put(bridge->pci_dev); > list_del(&bridge->list); > kfree(bridge); > > -- > 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 > > -- 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
