[PATCH net 3/3] net: stmmac: stop DMA when IRQ registration fails

[Daniel Machon]

Hi,

> Both __stmmac_open() and stmmac_xdp_open() start DMA before requesting
> IRQs. If IRQ registration fails, their error paths release descriptors
> and packet buffers while the DMA channels remain active.
> 
> Stop all DMA channels before releasing those resources, matching the
> normal close paths.
> 
> Found by inspection. On a BeagleV Ahead (TH1520), fault injection in
> both normal-open and native-XDP-open paths reached IRQ unwind with DMA
> active on the baseline kernel. With this change, the DMA process states
> were idle before unwind and resource cleanup in both paths.

This fix looks suspiciously similar to a fix already accepted into net-next [1].

> 
> Fixes: 523f11b5d4fd ("net: stmmac: move hardware setup for stmmac_open to new function")
> Fixes: ac746c8520d9 ("net: stmmac: enhance XDP ZC driver level switching performance")
> Assisted-by: LLM
> Signed-off-by: Karl Mehltretter <kmehltretter at gmail.com>
> ---
>  drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
> index 8fd7d2173..5c4df26a6 100644
> --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
> +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
> @@ -4206,6 +4206,7 @@ irq_error:
>  	for (chan = 0; chan < priv->plat->tx_queues_to_use; chan++)
>  		hrtimer_cancel(&priv->dma_conf.tx_queue[chan].txtimer);
>  
> +	stmmac_stop_all_dma(priv);
>  	stmmac_release_ptp(priv);
>  init_error:
>  	return ret;
> @@ -7259,6 +7260,7 @@ int stmmac_xdp_open(struct net_device *dev)
>  irq_error:
>  	for (chan = 0; chan < priv->plat->tx_queues_to_use; chan++)
>  		hrtimer_cancel(&priv->dma_conf.tx_queue[chan].txtimer);
> +	stmmac_stop_all_dma(priv);
>  
>  init_error:
>  	free_dma_desc_resources(priv, &priv->dma_conf);
> -- 
> 2.39.5 (Apple Git-154)
> 

[1] https://lore.kernel.org/netdev/32EB352EB66D74E7+20260827025415.2684733-1-zhaojinming@uniontech.com/