Subject: Re: [PATCH net-next v11 1/4] tun/tap: add ptr_ring consume helper with netdev queue wakeup

From: "Michael S. Tsirkin" <[email-masked]>
Date: Sat, 9 May 2026 18:44:49 -0400

On Sat, May 09, 2026 at 06:31:47PM +0200, Simon Schippers wrote:
> On 5/8/26 17:10, Simon Schippers wrote:
> > +static void tun_queue_purge(struct tun_struct *tun, struct tun_file *tfile)
> >  {
> >  	void *ptr;
> >  
> > -	while ((ptr = ptr_ring_consume(&tfile->tx_ring)) != NULL)
> > +	while ((ptr = tun_ring_consume(tun, tfile)) != NULL)
> >  		tun_ptr_free(ptr);
> >  
> >  	skb_queue_purge(&tfile->sk.sk_write_queue);
> 
> Sashiko is right once again. tun_ring_consume() in tun_queue_purge()
> operates on a tfile that is being torn down. Its queue_index is no
> longer valid. After the swap in __tun_detach(), it points to the
> netdev subqueue of a different tfile.
> --> We should not wake there.

Does it not exactly point at ntfile which is what we want to wake?

> I will swap tun_ring_consume() with ptr_ring_consume() again and
> submit a v12 :)

If so then maybe
netif_tx_wake_queue(netdev_get_tx_queue(tun->dev, index));

-- 
MST