Re: [PATCH net v2 0/3] Add missing xdp_do_flush() invocations.

Jesper Dangaard Brouer
2023-09-20T07:04:32Z

Hi Sebastian,

On 18/09/2023 17.36, Sebastian Andrzej Siewior wrote:
> Hi,
>
> I've been looking at the drivers/ XDP users and noticed that some
> XDP_REDIRECT user don't invoke xdp_do_flush() at the end.

I'm wondering if we could detect (and WARN) in the net core e.g.
net_rx_action() that a driver is missing a flush?

The idea could be to check the per CPU (struct) bpf_redirect_info.
Or check (per CPU) dev_flush_list.

If some is worried about performance implications, then we can hide this
under CONFIG_DEBUG_NET.

> v1…v2: https://lore.kernel.org/all/20230908135748.794163-1-bigeasy@linutronix.de
> - Collected tags.
> - Dropped the #4 patch which was touching cpu_map_bpf_prog_run()
> because it is not needed.
>

For the fixes in this set:

Acked-by: Jesper Dangaard Brouer <hawk@kernel.org>

Thanks for fixing these! - at it can lead to strange to debug cases.
--Jesper