[PATCH] dpaa2-switch: Fix interrupt storm after receiving bad if_id in IRQ handler

[Guenter Roeck]

Commit 31a7a0bbeb00 ("dpaa2-switch: add bounds check for if_id in IRQ
handler") introduces a range check for if_id to avoid an out-of-bounds
access. If an out-of-bounds if_id is detected, the interrupt status is
not cleared. This may result in an interrupt storm.

Clear the interrupt status after detecting an out-of-bounds if_id to avoid
the problem.

Found by an experimental AI code review agent at Google.

Fixes: 31a7a0bbeb00 ("dpaa2-switch: add bounds check for if_id in IRQ handler")
Cc: Jakub Kicinski <kuba@xxxxxxxxxx>
Cc: Junrui Luo <moonafterrain@xxxxxxxxxxx>
Signed-off-by: Guenter Roeck <linux@xxxxxxxxxxxx>
---
 drivers/net/ethernet/freescale/dpaa2/dpaa2-switch.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/freescale/dpaa2/dpaa2-switch.c b/drivers/net/ethernet/freescale/dpaa2/dpaa2-switch.c
index def2dd231d1f..b70a232a217e 100644
--- a/drivers/net/ethernet/freescale/dpaa2/dpaa2-switch.c
+++ b/drivers/net/ethernet/freescale/dpaa2/dpaa2-switch.c
@@ -1533,7 +1533,7 @@ static irqreturn_t dpaa2_switch_irq0_handler_thread(int irq_num, void *arg)
 	if_id = (status & 0xFFFF0000) >> 16;
 	if (if_id >= ethsw->sw_attr.num_ifs) {
 		dev_err(dev, "Invalid if_id %d in IRQ status\n", if_id);
-		goto out;
+		goto out_clear;
 	}
 	port_priv = ethsw->ports[if_id];
 
@@ -1553,6 +1553,7 @@ static irqreturn_t dpaa2_switch_irq0_handler_thread(int irq_num, void *arg)
 			dpaa2_switch_port_connect_mac(port_priv);
 	}
 
+out_clear:
 	err = dpsw_clear_irq_status(ethsw->mc_io, 0, ethsw->dpsw_handle,
 				    DPSW_IRQ_INDEX_IF, status);
 	if (err)
-- 
2.45.2