[PATCH 3.18 02/13] PCI: keystone: Fix interrupt-controller-node lookup

From: Greg Kroah-Hartman
Date: Mon Feb 26 2018 - 16:07:41 EST


3.18-stable review patch. If anyone has any objections, please let me know.

------------------

From: Johan Hovold <johan@xxxxxxxxxx>

commit eac56aa3bc8af3d9b9850345d0f2da9d83529134 upstream.

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>
Signed-off-by: Johan Hovold <johan@xxxxxxxxxx>
[lorenzo.pieralisi@xxxxxxx: updated commit subject]
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@xxxxxxx>
[johan: backport to 4.4]
Signed-off-by: Johan Hovold <johan@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
drivers/pci/host/pci-keystone.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)

--- a/drivers/pci/host/pci-keystone.c
+++ b/drivers/pci/host/pci-keystone.c
@@ -179,14 +179,16 @@ static int ks_pcie_get_irq_controller_in
}

/* 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);
goto out;
}
temp = of_irq_count(*np_temp);
- if (!temp)
+ if (!temp) {
+ of_node_put(*np_temp);
goto out;
+ }
if (temp > max_host_irqs)
dev_warn(dev, "Too many %s interrupts defined %u\n",
(legacy ? "legacy" : "MSI"), temp);
@@ -200,6 +202,9 @@ static int ks_pcie_get_irq_controller_in
if (host_irqs[temp] < 0)
break;
}
+
+ of_node_put(*np_temp);
+
if (temp) {
*num_irqs = temp;
ret = 0;