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

[Karl Mehltretter]

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.

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)