[v2] pci: pcie-xilinx: fix a missing-check bug for __get_free_pages
diff mbox series

Message ID 20190323210423.8881-1-pakki001@umn.edu
State New
Headers show
Series
  • [v2] pci: pcie-xilinx: fix a missing-check bug for __get_free_pages
Related show

Commit Message

Aditya Pakki March 23, 2019, 9:04 p.m. UTC
In case __get_free_pages fail, the fix returns error upstream
to avoid NULL pointer dereference.

Signed-off-by: Aditya Pakki <pakki001@umn.edu>

---
v1: Return error upstream as suggested by Steven
---
 drivers/pci/controller/pcie-xilinx.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

Comments

Steven Price March 25, 2019, 12:08 p.m. UTC | #1
On 23/03/2019 21:04, Aditya Pakki wrote:
> In case __get_free_pages fail, the fix returns error upstream
> to avoid NULL pointer dereference.
> 
> Signed-off-by: Aditya Pakki <pakki001@umn.edu>

Reviewed-by: Steven Price <steven.price@arm.com>

> 
> ---
> v1: Return error upstream as suggested by Steven
> ---
>  drivers/pci/controller/pcie-xilinx.c | 11 +++++++++--
>  1 file changed, 9 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/pci/controller/pcie-xilinx.c b/drivers/pci/controller/pcie-xilinx.c
> index 9bd1a35cd5d8..91d8945bfb0c 100644
> --- a/drivers/pci/controller/pcie-xilinx.c
> +++ b/drivers/pci/controller/pcie-xilinx.c
> @@ -335,15 +335,19 @@ static const struct irq_domain_ops msi_domain_ops = {
>  /**
>   * xilinx_pcie_enable_msi - Enable MSI support
>   * @port: PCIe port information
> + * Return: 0 on success, negative error on failure
>   */
> -static void xilinx_pcie_enable_msi(struct xilinx_pcie_port *port)
> +static int xilinx_pcie_enable_msi(struct xilinx_pcie_port *port)
>  {
>  	phys_addr_t msg_addr;
>  
>  	port->msi_pages = __get_free_pages(GFP_KERNEL, 0);
> +	if (!port->msi_pages)
> +		return -ENOMEM;
>  	msg_addr = virt_to_phys((void *)port->msi_pages);
>  	pcie_write(port, 0x0, XILINX_PCIE_REG_MSIBASE1);
>  	pcie_write(port, msg_addr, XILINX_PCIE_REG_MSIBASE2);
> +	return 0;
>  }
>  
>  /* INTx Functions */
> @@ -498,6 +502,7 @@ static int xilinx_pcie_init_irq_domain(struct xilinx_pcie_port *port)
>  	struct device *dev = port->dev;
>  	struct device_node *node = dev->of_node;
>  	struct device_node *pcie_intc_node;
> +	int ret;
>  
>  	/* Setup INTx */
>  	pcie_intc_node = of_get_next_child(node, NULL);
> @@ -526,7 +531,9 @@ static int xilinx_pcie_init_irq_domain(struct xilinx_pcie_port *port)
>  			return -ENODEV;
>  		}
>  
> -		xilinx_pcie_enable_msi(port);
> +		ret = xilinx_pcie_enable_msi(port);
> +		if (ret)
> +			return ret;
>  	}
>  
>  	return 0;
>
Robin Murphy March 26, 2019, 1:01 p.m. UTC | #2
On 23/03/2019 21:04, Aditya Pakki wrote:
> In case __get_free_pages fail, the fix returns error upstream
> to avoid NULL pointer dereference.

Where does msi_pages ever get dereferenced?

The logic here might actually still have a chance of working out OK with 
NULL depending on how the memory maps line up, but even if it doesn't, 
the problem is certainly not one of dereferencing.

Robin.

> Signed-off-by: Aditya Pakki <pakki001@umn.edu>
> 
> ---
> v1: Return error upstream as suggested by Steven
> ---
>   drivers/pci/controller/pcie-xilinx.c | 11 +++++++++--
>   1 file changed, 9 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/pci/controller/pcie-xilinx.c b/drivers/pci/controller/pcie-xilinx.c
> index 9bd1a35cd5d8..91d8945bfb0c 100644
> --- a/drivers/pci/controller/pcie-xilinx.c
> +++ b/drivers/pci/controller/pcie-xilinx.c
> @@ -335,15 +335,19 @@ static const struct irq_domain_ops msi_domain_ops = {
>   /**
>    * xilinx_pcie_enable_msi - Enable MSI support
>    * @port: PCIe port information
> + * Return: 0 on success, negative error on failure
>    */
> -static void xilinx_pcie_enable_msi(struct xilinx_pcie_port *port)
> +static int xilinx_pcie_enable_msi(struct xilinx_pcie_port *port)
>   {
>   	phys_addr_t msg_addr;
>   
>   	port->msi_pages = __get_free_pages(GFP_KERNEL, 0);
> +	if (!port->msi_pages)
> +		return -ENOMEM;
>   	msg_addr = virt_to_phys((void *)port->msi_pages);
>   	pcie_write(port, 0x0, XILINX_PCIE_REG_MSIBASE1);
>   	pcie_write(port, msg_addr, XILINX_PCIE_REG_MSIBASE2);
> +	return 0;
>   }
>   
>   /* INTx Functions */
> @@ -498,6 +502,7 @@ static int xilinx_pcie_init_irq_domain(struct xilinx_pcie_port *port)
>   	struct device *dev = port->dev;
>   	struct device_node *node = dev->of_node;
>   	struct device_node *pcie_intc_node;
> +	int ret;
>   
>   	/* Setup INTx */
>   	pcie_intc_node = of_get_next_child(node, NULL);
> @@ -526,7 +531,9 @@ static int xilinx_pcie_init_irq_domain(struct xilinx_pcie_port *port)
>   			return -ENODEV;
>   		}
>   
> -		xilinx_pcie_enable_msi(port);
> +		ret = xilinx_pcie_enable_msi(port);
> +		if (ret)
> +			return ret;
>   	}
>   
>   	return 0;
>

Patch
diff mbox series

diff --git a/drivers/pci/controller/pcie-xilinx.c b/drivers/pci/controller/pcie-xilinx.c
index 9bd1a35cd5d8..91d8945bfb0c 100644
--- a/drivers/pci/controller/pcie-xilinx.c
+++ b/drivers/pci/controller/pcie-xilinx.c
@@ -335,15 +335,19 @@  static const struct irq_domain_ops msi_domain_ops = {
 /**
  * xilinx_pcie_enable_msi - Enable MSI support
  * @port: PCIe port information
+ * Return: 0 on success, negative error on failure
  */
-static void xilinx_pcie_enable_msi(struct xilinx_pcie_port *port)
+static int xilinx_pcie_enable_msi(struct xilinx_pcie_port *port)
 {
 	phys_addr_t msg_addr;
 
 	port->msi_pages = __get_free_pages(GFP_KERNEL, 0);
+	if (!port->msi_pages)
+		return -ENOMEM;
 	msg_addr = virt_to_phys((void *)port->msi_pages);
 	pcie_write(port, 0x0, XILINX_PCIE_REG_MSIBASE1);
 	pcie_write(port, msg_addr, XILINX_PCIE_REG_MSIBASE2);
+	return 0;
 }
 
 /* INTx Functions */
@@ -498,6 +502,7 @@  static int xilinx_pcie_init_irq_domain(struct xilinx_pcie_port *port)
 	struct device *dev = port->dev;
 	struct device_node *node = dev->of_node;
 	struct device_node *pcie_intc_node;
+	int ret;
 
 	/* Setup INTx */
 	pcie_intc_node = of_get_next_child(node, NULL);
@@ -526,7 +531,9 @@  static int xilinx_pcie_init_irq_domain(struct xilinx_pcie_port *port)
 			return -ENODEV;
 		}
 
-		xilinx_pcie_enable_msi(port);
+		ret = xilinx_pcie_enable_msi(port);
+		if (ret)
+			return ret;
 	}
 
 	return 0;