FAILED: patch "[PATCH] PCI: keystone: Fix interrupt-controller-node lookup" failed to apply to 4.4-stable tree

FAILED: patch "[PATCH] PCI: keystone: Fix interrupt-controller-node lookup" failed to apply to 4.4-stable tree

[gregkh]

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@vger.kernel.org>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

>From eac56aa3bc8af3d9b9850345d0f2da9d83529134 Mon Sep 17 00:00:00 2001
From: Johan Hovold <johan@kernel.org>
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@vger.kernel.org>     # 3.18
Acked-by: Murali Karicheri <m-karicheri2@ti.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
[lorenzo.pieralisi@arm.com: updated commit subject]
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>

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;

Re: FAILED: patch "[PATCH] PCI: keystone: Fix interrupt-controller-node lookup" failed to apply to 4.4-stable tree

[Lorenzo Pieralisi]

Hi Johan,

On Tue, Feb 20, 2018 at 12:04:10PM +0100, gregkh@linuxfoundation.org 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@vger.kernel.org>.

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@kernel.org>
> 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@vger.kernel.org>     # 3.18
> Acked-by: Murali Karicheri <m-karicheri2@ti.com>
> Signed-off-by: Johan Hovold <johan@kernel.org>
> [lorenzo.pieralisi@arm.com: updated commit subject]
> Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
> 
> 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;
>