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In some circumstances, such as with bridging, it is possible that the stack will add a devices own MAC address to its unicast address list. If, later, the stack deletes this address, then the i40e driver will receive a request to remove this address. The driver stores its current MAC address as part of the MAC/VLAN hash array, since it is convenient and matches exactly how the hardware expects to be told which traffic to receive. This causes a problem, since for more devices, the MAC address is stored separately, and requests to delete a unicast address should not have the ability to remove the filter for the MAC address. Fix this by forcing a check on every address sync to ensure we do not remove the device address. There is a very narrow possibility of a race between .set_mac and .set_rx_mode, if we don't change netdev->dev_addr before updating our internal MAC list in .set_mac. This might be possible if .set_rx_mode is going to remove MAC "XYZ" from the list, at the same time as .set_mac changes our dev_addr to MAC "XYZ", we might possibly queue a delete, then an add in .set_mac, then queue a delete in .set_rx_mode's dev_uc_sync and then update netdev->dev_addr. We can avoid this by moving the copy into dev_addr prior to the changes to the MAC filter list. A similar race on the other side does not cause problems, as if we're changing our MAC form A to B, and we race with .set_rx_mode, it could queue a delete from A, we'd update our address, and allow the delete. This seems like a race, but in reality we're about to queue a delete of A anyways, so it would not cause any issues. A race in the initialization code is unlikely because the netdevice has not yet been fully initialized and the stack should not be adding or removing addresses yet. Note that we don't (yet) need similar code for the VF driver because it does not make use of __dev_uc_sync and __dev_mc_sync, but instead roles its own method for handling updates to the MAC/VLAN list, which already has code to protect against removal of the hardware address. Signed-off-by: Jacob Keller <jacob.e.keller@intel.com> Tested-by: Andrew Bowers <andrewx.bowers@intel.com> Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.