linux-kernel - Re: [Intel-wired-lan] [PATCH v2] i40e: add an error handling path in

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Message-ID: <20260131070335.38303-1-kohei@enjuk.jp>
Date: Sat, 31 Jan 2026 07:02:38 +0000
From: Kohei Enju <kohei@...uk.jp>
To: kohei@...uk.jp
Cc: andrew+netdev@...n.ch, anthony.l.nguyen@...el.com, bjorn@...nel.org,
        daniel@...earbox.net, davem@...emloft.net, edumazet@...gle.com,
        intel-wired-lan@...ts.osuosl.org, kuba@...nel.org,
        lihaoxiang@...c.iscas.ac.cn, linux-kernel@...r.kernel.org,
        magnus.karlsson@...el.com, netdev@...r.kernel.org, pabeni@...hat.com,
        przemyslaw.kitszel@...el.com, stable@...r.kernel.org
Subject: Re: [Intel-wired-lan] [PATCH v2] i40e: add an error handling path in

On Sat, 31 Jan 2026 06:12:12 +0000, Kohei Enju wrote:

> On Sat, 31 Jan 2026 13:52:17 +0800, Haoxiang Li wrote:
> 
> > In i40e_xsk_pool_enable(), add an error handling path to
> > prevent potential memory leaks.
> > 
> > Fixes: 1742b3d52869 ("xsk: i40e: ice: ixgbe: mlx5: Pass buffer pool to driver instead of umem")
> > Cc: stable@...r.kernel.org
> > Signed-off-by: Haoxiang Li <lihaoxiang@...c.iscas.ac.cn>
> > ---
> > Changes in v2:
> > - Add a Fixes tag. Thanks, Paul!
> > - Replace unmap with i40e_xsk_pool_disable() to prevent
> > a limbo state of queues. Thanks, Maciej! 
> > ---
> >  drivers/net/ethernet/intel/i40e/i40e_xsk.c | 11 +++++++----
> >  1 file changed, 7 insertions(+), 4 deletions(-)
> > 
> > diff --git a/drivers/net/ethernet/intel/i40e/i40e_xsk.c b/drivers/net/ethernet/intel/i40e/i40e_xsk.c
> > index 9f47388eaba5..a72a309540c3 100644
> > --- a/drivers/net/ethernet/intel/i40e/i40e_xsk.c
> > +++ b/drivers/net/ethernet/intel/i40e/i40e_xsk.c
> > @@ -108,23 +108,26 @@ static int i40e_xsk_pool_enable(struct i40e_vsi *vsi,
> >  	if (if_running) {
> >  		err = i40e_queue_pair_disable(vsi, qid);
> >  		if (err)
> > -			return err;
> > +			goto err_out;
> >  
> >  		err = i40e_realloc_rx_xdp_bi(vsi->rx_rings[qid], true);
> >  		if (err)
> > -			return err;
> > +			goto err_out;
> >  
> >  		err = i40e_queue_pair_enable(vsi, qid);
> >  		if (err)
> > -			return err;
> > +			goto err_out;
> >  
> >  		/* Kick start the NAPI context so that receiving will start */
> >  		err = i40e_xsk_wakeup(vsi->netdev, qid, XDP_WAKEUP_RX);
> >  		if (err)
> > -			return err;
> > +			goto err_out;
> >  	}
> >  
> >  	return 0;
> > +
> > +err_out:
> > +	i40e_xsk_pool_disable(vsi, qid);
> 
> I think return err; is missing...
> 
> Also, since i40e_xsk_pool_disable is not declared before this line,
> compilation fails due to a 'Call to undeclared function
> i40e_xsk_pool_disable' error. Adding declaration or moving
> i40e_xsk_pool_enable() after i40e_xsk_pool_disable() is needed.

After skimming the code, I think i40e_xsk_pool_disable() can fail in
this error path, right? 

Let's assume a scenario that i40e_queue_pair_disable() succeeds but
i40e_realloc_rx_xdp_bi() fails in i40e_xsk_pool_enable(). 
At this point, i40e_enter_busy_conf() called by
i40e_queue_pair_disable() has set __I40E_CONFIG_BUSY state.

Then the err_out: path is executed and i40e_xsk_pool_disable() tries to
call i40e_queue_pair_disable() when if_running.
In this case, i40e_enter_busy_conf() fails because __I40E_CONFIG_BUSY is
set, and finally xsk_pool_dma_unmap() isn't called.

Do you have any thoughts on how to handle this case?

Thanks.

> 
> >  }
> >  
> >  /**
> > -- 
> > 2.25.1