[PATCH] pci: pcie-xilinx: fix a missing-check bug for __get_free_pages

[PATCH] pci: pcie-xilinx: fix a missing-check bug for __get_free_pages

[Kangjie Lu]

In case __get_free_pages fail, the fix returns to avoid NULL
pointer dereference.

Signed-off-by: Kangjie Lu <kjlu@umn.edu>
---
 drivers/pci/controller/pcie-xilinx.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/pci/controller/pcie-xilinx.c b/drivers/pci/controller/pcie-xilinx.c
index 9bd1a35cd5d8..b7083e995c45 100644
--- a/drivers/pci/controller/pcie-xilinx.c
+++ b/drivers/pci/controller/pcie-xilinx.c
@@ -341,6 +341,9 @@ static void xilinx_pcie_enable_msi(struct xilinx_pcie_port *port)
 	phys_addr_t msg_addr;
 
 	port->msi_pages = __get_free_pages(GFP_KERNEL, 0);
+	if (unlikely(!port->msi_pages))
+		return;
+
 	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);
-- 
2.17.1


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Re: [PATCH] pci: pcie-xilinx: fix a missing-check bug for __get_free_pages

[Steven Price]

On 14/03/2019 05:58, Kangjie Lu wrote:
> In case __get_free_pages fail, the fix returns to avoid NULL
> pointer dereference.
> 
> Signed-off-by: Kangjie Lu <kjlu@umn.edu>
> ---
>  drivers/pci/controller/pcie-xilinx.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/pci/controller/pcie-xilinx.c b/drivers/pci/controller/pcie-xilinx.c
> index 9bd1a35cd5d8..b7083e995c45 100644
> --- a/drivers/pci/controller/pcie-xilinx.c
> +++ b/drivers/pci/controller/pcie-xilinx.c
> @@ -341,6 +341,9 @@ static void xilinx_pcie_enable_msi(struct xilinx_pcie_port *port)
>  	phys_addr_t msg_addr;
>  
>  	port->msi_pages = __get_free_pages(GFP_KERNEL, 0);
> +	if (unlikely(!port->msi_pages))
> +		return;

Shouldn't the function return an error code for the calling function to
see? With this change the caller (xilinx_pcie_init_irq_domain) will
think that MSIs were enabled, but actually they weren't.

Steve

> +
>  	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);
> 


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[PATCH v2] pci: pcie-xilinx: fix a missing-check bug for __get_free_pages

[Kangjie Lu]

In case __get_free_pages fail, the fix returns -ENOMEMto avoid
NULL pointer dereference.

Signed-off-by: Kangjie Lu <kjlu@umn.edu>
Reviewed-by: Steven Price <steven.price@arm.com>
---
v2: caller is redefined to accept the error code, as suggested by
Steven Price <steven.price@arm.com>
---
 drivers/pci/controller/pcie-xilinx.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/drivers/pci/controller/pcie-xilinx.c b/drivers/pci/controller/pcie-xilinx.c
index 9bd1a35cd5d8..abc214e94f7c 100644
--- a/drivers/pci/controller/pcie-xilinx.c
+++ b/drivers/pci/controller/pcie-xilinx.c
@@ -336,14 +336,19 @@ static const struct irq_domain_ops msi_domain_ops = {
  * xilinx_pcie_enable_msi - Enable MSI support
  * @port: PCIe port information
  */
-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 (unlikely(!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 +503,7 @@ 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 +532,9 @@ 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;
-- 
2.17.1


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Re: [PATCH v2] pci: pcie-xilinx: fix a missing-check bug for __get_free_pages

[Bjorn Helgaas]

Hi Kangjie,

Thanks for the patch!

Please update the subject line like this:

  PCI: xilinx: Check for __get_free_pages() failure

You can always get a good idea of the style for subject lines by doing
something like this:

  git log --oneline --follow drivers/pci/controller/pcie-xilinx.c

On Mon, Mar 25, 2019 at 04:31:13PM -0500, Kangjie Lu wrote:
> In case __get_free_pages fail, the fix returns -ENOMEMto avoid
> NULL pointer dereference.

s/In case/If/
s/__get_free_pages/__get_free_pages()/
s/fail/fails/
s/the fix returns/return/
s/-ENOMEMto/-ENOMEM to/

> Signed-off-by: Kangjie Lu <kjlu@umn.edu>
> Reviewed-by: Steven Price <steven.price@arm.com>

I didn't see Steven's reviewed-by on the mailing list.  I did see his
*review*, but his "Reviewed-by: Steven Price <steven.price@arm.com>"
implies that he reviewed it *and* believes it to ready for merging
(see Documentation/process/submitting-patches.rst for all the
details).

So we should only add the Reviewed-by tag after Steven himself posts
it.

> ---
> v2: caller is redefined to accept the error code, as suggested by
> Steven Price <steven.price@arm.com>
> ---
>  drivers/pci/controller/pcie-xilinx.c | 12 ++++++++++--
>  1 file changed, 10 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/pci/controller/pcie-xilinx.c b/drivers/pci/controller/pcie-xilinx.c
> index 9bd1a35cd5d8..abc214e94f7c 100644
> --- a/drivers/pci/controller/pcie-xilinx.c
> +++ b/drivers/pci/controller/pcie-xilinx.c
> @@ -336,14 +336,19 @@ static const struct irq_domain_ops msi_domain_ops = {
>   * xilinx_pcie_enable_msi - Enable MSI support
>   * @port: PCIe port information
>   */
> -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 (unlikely(!port->msi_pages))
> +		return -ENOMEM;

No need to use "unlikely()" here.  It *is* unlikely that
__get_free_pages() will fail, but the annotation clutters the code a
bit, so I prefer to avoid it except for performance paths.

This should probably be documented somewhere in
Documentation/process/, but regrettably, it isn't (yet).

>  	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 +503,7 @@ 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 +532,9 @@ 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;
> -- 
> 2.17.1
> 
> 
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[PATCH v3] PCI: xilinx: Check for __get_free_pages() failure

[Kangjie Lu]

If __get_free_pages() fails, the patch returns -ENOMEM to avoid
NULL pointer dereference.

Signed-off-by: Kangjie Lu <kjlu@umn.edu>
---
v3: remove "unlikely", as suggested by Bjorn Helgaas.
v2: caller is redefined to accept the error code, as suggested by
Steven Price <steven.price@arm.com>
---
 drivers/pci/controller/pcie-xilinx.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/drivers/pci/controller/pcie-xilinx.c b/drivers/pci/controller/pcie-xilinx.c
index 9bd1a35cd5d8..abc214e94f7c 100644
--- a/drivers/pci/controller/pcie-xilinx.c
+++ b/drivers/pci/controller/pcie-xilinx.c
@@ -336,14 +336,19 @@ static const struct irq_domain_ops msi_domain_ops = {
  * xilinx_pcie_enable_msi - Enable MSI support
  * @port: PCIe port information
  */
-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 +503,7 @@ 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 +532,9 @@ 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;
-- 
2.17.1


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Re: [PATCH v3] PCI: xilinx: Check for __get_free_pages() failure

[Steven Price]

On 25/03/2019 22:19, Kangjie Lu wrote:
> If __get_free_pages() fails, the patch returns -ENOMEM to avoid

As Bjorn suggested s/the patch returns/return/ would suffice and is
slightly easier to read. But I'm happy either way.

> NULL pointer dereference.
> 
> Signed-off-by: Kangjie Lu <kjlu@umn.edu>

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

> ---
> v3: remove "unlikely", as suggested by Bjorn Helgaas.
> v2: caller is redefined to accept the error code, as suggested by
> Steven Price <steven.price@arm.com>
> ---
>  drivers/pci/controller/pcie-xilinx.c | 12 ++++++++++--
>  1 file changed, 10 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/pci/controller/pcie-xilinx.c b/drivers/pci/controller/pcie-xilinx.c
> index 9bd1a35cd5d8..abc214e94f7c 100644
> --- a/drivers/pci/controller/pcie-xilinx.c
> +++ b/drivers/pci/controller/pcie-xilinx.c
> @@ -336,14 +336,19 @@ static const struct irq_domain_ops msi_domain_ops = {
>   * xilinx_pcie_enable_msi - Enable MSI support
>   * @port: PCIe port information
>   */
> -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 +503,7 @@ 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 +532,9 @@ 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;
> 


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Re: [PATCH v3] PCI: xilinx: Check for __get_free_pages() failure

[Mukesh Ojha]

On 3/26/2019 3:49 AM, Kangjie Lu wrote:
> If __get_free_pages() fails, the patch returns -ENOMEM to avoid
> NULL pointer dereference.
>
> Signed-off-by: Kangjie Lu <kjlu@umn.edu>


Reviewed-by: Mukesh Ojha <mojha@codeaurora.org>

-Mukesh

> ---
> v3: remove "unlikely", as suggested by Bjorn Helgaas.
> v2: caller is redefined to accept the error code, as suggested by
> Steven Price <steven.price@arm.com>
> ---
>   drivers/pci/controller/pcie-xilinx.c | 12 ++++++++++--
>   1 file changed, 10 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/pci/controller/pcie-xilinx.c b/drivers/pci/controller/pcie-xilinx.c
> index 9bd1a35cd5d8..abc214e94f7c 100644
> --- a/drivers/pci/controller/pcie-xilinx.c
> +++ b/drivers/pci/controller/pcie-xilinx.c
> @@ -336,14 +336,19 @@ static const struct irq_domain_ops msi_domain_ops = {
>    * xilinx_pcie_enable_msi - Enable MSI support
>    * @port: PCIe port information
>    */
> -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 +503,7 @@ 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 +532,9 @@ 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;

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Re: [PATCH v3] PCI: xilinx: Check for __get_free_pages() failure

[Lorenzo Pieralisi]

On Mon, Mar 25, 2019 at 05:19:09PM -0500, Kangjie Lu wrote:
> If __get_free_pages() fails, the patch returns -ENOMEM to avoid
> NULL pointer dereference.
> 
> Signed-off-by: Kangjie Lu <kjlu@umn.edu>
> ---
> v3: remove "unlikely", as suggested by Bjorn Helgaas.
> v2: caller is redefined to accept the error code, as suggested by
> Steven Price <steven.price@arm.com>
> ---
>  drivers/pci/controller/pcie-xilinx.c | 12 ++++++++++--
>  1 file changed, 10 insertions(+), 2 deletions(-)

Updated commit log and applied to pci/xilinx for v5.2.

Thanks,
Lorenzo

> diff --git a/drivers/pci/controller/pcie-xilinx.c b/drivers/pci/controller/pcie-xilinx.c
> index 9bd1a35cd5d8..abc214e94f7c 100644
> --- a/drivers/pci/controller/pcie-xilinx.c
> +++ b/drivers/pci/controller/pcie-xilinx.c
> @@ -336,14 +336,19 @@ static const struct irq_domain_ops msi_domain_ops = {
>   * xilinx_pcie_enable_msi - Enable MSI support
>   * @port: PCIe port information
>   */
> -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 +503,7 @@ 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 +532,9 @@ 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;
> -- 
> 2.17.1
> 

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