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 
> ---
>  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);
> 

[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 
---
 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