[PATCH v2] PCI: keystone: fix interrupt-controller-node lookup

From: Johan Hovold
Date: Fri Nov 17 2017 - 08:40:56 EST


Fix child-node lookup during initialisation which was using the wrong
OF-helper and ended up searching the whole device tree depth-first
starting at the parent rather than just matching on its children.

To make things worse, the parent pci node could end up being prematurely
freed as of_find_node_by_name() drops a reference to its first argument.
Any matching child interrupt-controller node was also leaked.

Fixes: 0c4ffcfe1fbc ("PCI: keystone: Add TI Keystone PCIe driver")
Cc: stable <stable@xxxxxxxxxxxxxxx> # 3.18
Acked-by: Murali Karicheri <m-karicheri2@xxxxxx>
Acked-by: Lorenzo Pieralisi <lorenzo.pieralisi@xxxxxxx>
Signed-off-by: Johan Hovold <johan@xxxxxxxxxx>
---

v2
- amend commit message and mention explicitly that of_find_node_by_name()
drops a reference to the start node
- add Murali's and Lorenzo's acks


drivers/pci/dwc/pci-keystone.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/pci/dwc/pci-keystone.c b/drivers/pci/dwc/pci-keystone.c
index 5bee3af47588..39405598b22d 100644
--- a/drivers/pci/dwc/pci-keystone.c
+++ b/drivers/pci/dwc/pci-keystone.c
@@ -178,7 +178,7 @@ static int ks_pcie_get_irq_controller_info(struct keystone_pcie *ks_pcie,
}

/* interrupt controller is in a child node */
- *np_temp = of_find_node_by_name(np_pcie, controller);
+ *np_temp = of_get_child_by_name(np_pcie, controller);
if (!(*np_temp)) {
dev_err(dev, "Node for %s is absent\n", controller);
return -EINVAL;
@@ -187,6 +187,7 @@ static int ks_pcie_get_irq_controller_info(struct keystone_pcie *ks_pcie,
temp = of_irq_count(*np_temp);
if (!temp) {
dev_err(dev, "No IRQ entries in %s\n", controller);
+ of_node_put(*np_temp);
return -EINVAL;
}

@@ -204,6 +205,8 @@ static int ks_pcie_get_irq_controller_info(struct keystone_pcie *ks_pcie,
break;
}

+ of_node_put(*np_temp);
+
if (temp) {
*num_irqs = temp;
return 0;
--
2.15.0