[PATCH v2 1/2] of/irq: Fix device node refcount leak in of_check_msi_parent()

[Fuad Tabba <fuad.tabba@linux.dev>]

of_msi_xlate() documents @msi_np as a filter when it points at a node on
entry, handing back a reference only when it points at NULL. The msi-map
branch does that. of_check_msi_parent() keeps the reference from the 1:1
msi-parent match either way.

pci_msi_domain_get_msi_rid() is the only caller that passes a node in,
from irq_domain_get_of_node(), and it puts nothing, so a 1:1 match there
leaks the MSI controller node.

Fixes: 119aaeed0b67 ("of/irq: Add msi-parent check to of_msi_xlate()")
Reported-by: Sashiko <sashiko-bot@kernel.org>
Closes: https://lore.kernel.org/all/20260826113604.010C01F000E9@smtp.kernel.org/
Signed-off-by: Fuad Tabba <fuad.tabba@linux.dev>
---
 drivers/of/irq.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/of/irq.c b/drivers/of/irq.c
index ec035367c9500..109c54f346479 100644
--- a/drivers/of/irq.c
+++ b/drivers/of/irq.c
@@ -785,7 +785,7 @@ static int of_check_msi_parent(struct device_node *dev_node, struct device_node
 	if ((*msi_node && *msi_node != msi_spec.np) || msi_spec.args_count != 0)
 		ret = -EINVAL;
 
-	if (!ret) {
+	if (!ret && !*msi_node) {
 		/* Return with a node reference held */
 		*msi_node = msi_spec.np;
 		return 0;
-- 
2.39.5