On Thu, Mar 11, 2021 at 12:43 PM Jakub Kicinski <kuba@xxxxxxxxxx> wrote: > > Is this a theoretical issues or do you see a path where it triggers? > > Who are the callers sending frames to a device which went down? This is a theoretical issue. I didn't see this issue in practice. When "__dev_queue_xmit" and "sch_direct_xmit" call "dev_hard_start_xmit", there appears to be no locking mechanism preventing the netif from going down while "dev_hard_start_xmit" is doing its work. David once confirmed in an email that a driver's "ndo_stop" function would indeed race with its "ndo_start_xmit" function: https://lore.kernel.org/netdev/20190520.200922.2277656639346033061.davem@xxxxxxxxxxxxx/
