[PATCH v2 2/9] of/irq: Fix device node refcount leakage in API of_irq_parse_one()

[Zijun Hu]

From: Zijun Hu <quic_zijuhu@xxxxxxxxxxx>

of_irq_parse_one(@int_gen_dev, i, ...) will leak refcount of @i_th_phandle

int_gen_dev {
    ...
    interrupts-extended = ..., <&i_th_phandle ...>, ...;
    ...
};

Refcount of @i_th_phandle is increased by of_parse_phandle_with_args()
but is not decreased by API of_irq_parse_one() before return, so causes
refcount leakage.

Fix by putting the node's refcount before return as the other branch does.
Also add comments about refcount of node @out_irq->np got by the API.

Fixes: 79d9701559a9 ("of/irq: create interrupts-extended property")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Zijun Hu <quic_zijuhu@xxxxxxxxxxx>
---
 drivers/of/irq.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/of/irq.c b/drivers/of/irq.c
index 6c843d54ebb116132144e6300d6d7ce94e763cf8..d88719c316a3931502c34a65b2db8921f7528d99 100644
--- a/drivers/of/irq.c
+++ b/drivers/of/irq.c
@@ -339,6 +339,8 @@ EXPORT_SYMBOL_GPL(of_irq_parse_raw);
  * This function resolves an interrupt for a node by walking the interrupt tree,
  * finding which interrupt controller node it is attached to, and returning the
  * interrupt specifier that can be used to retrieve a Linux IRQ number.
+ *
+ * Note: refcount of node @out_irq->np is increased by 1 on success.
  */
 int of_irq_parse_one(struct device_node *device, int index, struct of_phandle_args *out_irq)
 {
@@ -367,8 +369,11 @@ int of_irq_parse_one(struct device_node *device, int index, struct of_phandle_ar
 	/* Try the new-style interrupts-extended first */
 	res = of_parse_phandle_with_args(device, "interrupts-extended",
 					"#interrupt-cells", index, out_irq);
-	if (!res)
-		return of_irq_parse_raw(addr_buf, out_irq);
+	if (!res) {
+		p = out_irq->np;
+		res = of_irq_parse_raw(addr_buf, out_irq);
+		goto out;
+	}
 
 	/* Look for the interrupt parent. */
 	p = of_irq_find_parent(device);

-- 
2.34.1