Re: [PATCH] PCI: imx6: Fix a "Null pointer dereference" issue

[Bjorn Helgaas]

On Wed, Sep 11, 2024 at 08:50:57PM +0800, Qianqiang Liu wrote:
> The "resource_list_first_type" function may return NULL, which
> will make "entry->offset" dereferences a NULL pointer.
> 
> Signed-off-by: Qianqiang Liu <qianqiang.liu@xxxxxxx>
> ---
>  drivers/pci/controller/dwc/pci-imx6.c | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/pci/controller/dwc/pci-imx6.c b/drivers/pci/controller/dwc/pci-imx6.c
> index 0dbc333adcff..04e90ba4e7d6 100644
> --- a/drivers/pci/controller/dwc/pci-imx6.c
> +++ b/drivers/pci/controller/dwc/pci-imx6.c
> @@ -1017,13 +1017,14 @@ static u64 imx_pcie_cpu_addr_fixup(struct dw_pcie *pcie, u64 cpu_addr)
>  	struct imx_pcie *imx_pcie = to_imx_pcie(pcie);
>  	struct dw_pcie_rp *pp = &pcie->pp;
>  	struct resource_entry *entry;
> -	unsigned int offset;
> +	unsigned int offset = 0;
>  
>  	if (!(imx_pcie->drvdata->flags & IMX_PCIE_FLAG_CPU_ADDR_FIXUP))
>  		return cpu_addr;
>  
>  	entry = resource_list_first_type(&pp->bridge->windows, IORESOURCE_MEM);
> -	offset = entry->offset;
> +	if (entry)
> +		offset = entry->offset;
>  
>  	return (cpu_addr - offset);
>  }

I made the edit I proposed here:
https://lore.kernel.org/r/20240911140721.GA630378@bhelgaas

Please double-check it at:
https://git.kernel.org/pub/scm/linux/kernel/git/pci/pci.git/commit/?id=c2699778e6be