Re: [PATCH] arm64: PCI: free all allocated memory in case of failure

[Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>]

On Fri, May 12, 2017 at 05:57:47PM +0800, Timmy Li wrote:
> There are some memory allocations in pci_acpi_scan_root(). But
> ri, root_ops and ri->cfg are not freed properly in failure cases,
> which results in memory leaks. This patch fixes the potential
> memory leaks.
> 
> Signed-off-by: Timmy Li <lixiaoping3@huawei.com>
> ---
>  arch/arm64/kernel/pci.c | 22 ++++++++++++++--------
>  1 file changed, 14 insertions(+), 8 deletions(-)
> 
> diff --git a/arch/arm64/kernel/pci.c b/arch/arm64/kernel/pci.c
> index 4f0e3eb..e7e88ce 100644
> --- a/arch/arm64/kernel/pci.c
> +++ b/arch/arm64/kernel/pci.c
> @@ -188,25 +188,22 @@ struct pci_bus *pci_acpi_scan_root(struct acpi_pci_root *root)
>  
>  	ri = kzalloc_node(sizeof(*ri), GFP_KERNEL, node);
>  	if (!ri)
> -		return NULL;
> +		goto err_allocri;
>  
>  	root_ops = kzalloc_node(sizeof(*root_ops), GFP_KERNEL, node);
>  	if (!root_ops)
> -		return NULL;
> +		goto err_allocops;
>  
>  	ri->cfg = pci_acpi_setup_ecam_mapping(root);
> -	if (!ri->cfg) {
> -		kfree(ri);
> -		kfree(root_ops);
> -		return NULL;
> -	}
> +	if (!ri->cfg)
> +		goto err_ecam;
>  
>  	root_ops->release_info = pci_acpi_generic_release_info;

You are missing this ^^^^^^^^^

>  	root_ops->prepare_resources = pci_acpi_root_prepare_resources;
>  	root_ops->pci_ops = &ri->cfg->ops->pci_ops;
>  	bus = acpi_pci_root_create(root, root_ops, &ri->common, ri->cfg);
>  	if (!bus)

And how it works if (bus == NULL) here.

Lorenzo

> -		return NULL;
> +		goto err_rootcreate;
>  
>  	pci_bus_size_bridges(bus);
>  	pci_bus_assign_resources(bus);
> @@ -215,6 +212,15 @@ struct pci_bus *pci_acpi_scan_root(struct acpi_pci_root *root)
>  		pcie_bus_configure_settings(child);
>  
>  	return bus;
> +
> +err_rootcreate:
> +	pci_ecam_free(ri->cfg);
> +err_ecam:
> +	kfree(root_ops);
> +err_allocops:
> +	kfree(ri);
> +err_allocri:
> +	return NULL;
>  }
>  
>  void pcibios_add_bus(struct pci_bus *bus)
> -- 
> 1.9.1
> 
>