On Wed, Apr 30, 2014 at 3:41 AM, Bjorn Helgaas <bhelgaas@xxxxxxxxxx> wrote: > On Tue, Apr 01, 2014 at 09:32:59PM -0400, Bandan Das wrote: >> >> While using the new_id interface, the user can unintentionally feed >> incorrect values if the driver static table has a matching entry. >> This is possible since only the device and vendor fields are >> mandatory and the rest are optional. As a result, store_new_id >> will fill in default values that are then passed on to the driver >> and can have unintended consequences. >> >> As an example, consider the ixgbe driver and the 82599EB network card : >> echo "8086 10fb" > /sys/bus/pci/drivers/ixgbe/new_id >> >> This will pass a driver_data value of 0 to the driver whereas >> the index 0 in ixgbe actually points to a different set of card >> operations. >> >> This change returns an error if the user attempts to add a dynid for >> a vendor/device combination for which a static entry already exists. >> However, if the user intentionally wants a different set of values, >> she must provide all the 7 fields and that will be accepted. >> >> In KVM/device assignment scenario, the user might want >> to bind a device back to the host driver by writing to new_id >> and trip on a possible null pointer dereference. It's not directly related to this patch, but I have a problem with this interface. iwlwifi.ko stores internal pointer in private_data field. So, it's hard to guess right one for adding new alias. Currently I'm using CONFIG_KALLSYMS_ALL=y, but it seems so ugly. I was thinking about adding new interface: "clone_id" (or "dup_id") which would make a copy of existing entry but with different product:vendor id. And I mostly have a patch for that. Or it's would be better to fix that driver (replace opaque pointer with some stable indexes)? >> >> Signed-off-by: Bandan Das <bsd@xxxxxxxxxx> > > Applied with Alex's ack to pci/misc for v3.16, thanks! > -- 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
