Subject: Re: BPF/XDP: kernel panic when removing an interface that is an xdp_redirect target

From: Jakub Kicinski <[email-masked]>
Date: Wed, 8 Nov 2023 17:52:15 -0800

On Wed, 8 Nov 2023 13:30:21 -0800 Nelson, Shannon wrote:
> > Another source of a bug like this could be that your driver does not in
> > fact call xdp_do_flush() before exiting its NAPI cycle, so that there
> > will be packets from the previous cycle in the bq queue, in which case
> > the assumption mentioned in the linked document obviously breaks down.
> > But that would also be a driver bug :)  
> 
> We do call the xdp_do_flush() at the end of the NAPI cycle, just before 
> calling napi_complete_done().

Just to be sure - flush has to happen on every cycle, not only
before calling napi_complete_done().