Hi Johan,
On Tue, Feb 20, 2018 at 12:04:10PM +0100, gregkh@xxxxxxxxxxxxxxxxxxx wrote:
>
> The patch below does not apply to the 4.4-stable tree.
> If someone wants it applied there, or to any other stable or longterm
> tree, then please email the backport, including the original git commit
> id to <stable@xxxxxxxxxxxxxxx>.
I think we should send a backport asap given what Greg reported and our
evaluation of the issue the patch is fixing, I would expect you to do
it, please let me know if you are not able to and I will send it myself.
Thanks,
Lorenzo
> thanks,
>
> greg k-h
>
> ------------------ original commit in Linus's tree ------------------
>
> From eac56aa3bc8af3d9b9850345d0f2da9d83529134 Mon Sep 17 00:00:00 2001
> From: Johan Hovold <johan@xxxxxxxxxx>
> Date: Fri, 17 Nov 2017 14:38:31 +0100
> Subject: [PATCH] PCI: keystone: Fix interrupt-controller-node lookup
>
> 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>
>
> 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;
>