On Thu, Aug 28, 2025 at 10:17:17AM +0800, Chen Wang wrote:
> From: Chen Wang <unicorn_wang@xxxxxxxxxxx>
>
> ops of struct cdns_pcie may be NULL, direct use
> will result in a null pointer error.
>
> Add checking of pcie->ops before using it.
>
> Fixes: 40d957e6f9eb ("PCI: cadence: Add support to start link and verify link status")
Do you observe this NULL pointer dereference with an existing driver?
If this is only to make it possible to add a new driver that doesn't
supply a pcie->ops pointer, it doesn't need a Fixes: tag because
there's not a problem with existing drivers and this change would not
need to be backported.
If it *is* a problem with an existing driver, please point out which
one.
> Signed-off-by: Chen Wang <unicorn_wang@xxxxxxxxxxx>
> ---
> drivers/pci/controller/cadence/pcie-cadence-host.c | 2 +-
> drivers/pci/controller/cadence/pcie-cadence.c | 4 ++--
> drivers/pci/controller/cadence/pcie-cadence.h | 6 +++---
> 3 files changed, 6 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/pci/controller/cadence/pcie-cadence-host.c b/drivers/pci/controller/cadence/pcie-cadence-host.c
> index 59a4631de79f..fffd63d6665e 100644
> --- a/drivers/pci/controller/cadence/pcie-cadence-host.c
> +++ b/drivers/pci/controller/cadence/pcie-cadence-host.c
> @@ -531,7 +531,7 @@ static int cdns_pcie_host_init_address_translation(struct cdns_pcie_rc *rc)
> cdns_pcie_writel(pcie, CDNS_PCIE_AT_OB_REGION_PCI_ADDR1(0), addr1);
> cdns_pcie_writel(pcie, CDNS_PCIE_AT_OB_REGION_DESC1(0), desc1);
>
> - if (pcie->ops->cpu_addr_fixup)
> + if (pcie->ops && pcie->ops->cpu_addr_fixup)
> cpu_addr = pcie->ops->cpu_addr_fixup(pcie, cpu_addr);
>
> addr0 = CDNS_PCIE_AT_OB_REGION_CPU_ADDR0_NBITS(12) |
> diff --git a/drivers/pci/controller/cadence/pcie-cadence.c b/drivers/pci/controller/cadence/pcie-cadence.c
> index 70a19573440e..61806bbd8aa3 100644
> --- a/drivers/pci/controller/cadence/pcie-cadence.c
> +++ b/drivers/pci/controller/cadence/pcie-cadence.c
> @@ -92,7 +92,7 @@ void cdns_pcie_set_outbound_region(struct cdns_pcie *pcie, u8 busnr, u8 fn,
> cdns_pcie_writel(pcie, CDNS_PCIE_AT_OB_REGION_DESC1(r), desc1);
>
> /* Set the CPU address */
> - if (pcie->ops->cpu_addr_fixup)
> + if (pcie->ops && pcie->ops->cpu_addr_fixup)
> cpu_addr = pcie->ops->cpu_addr_fixup(pcie, cpu_addr);
>
> addr0 = CDNS_PCIE_AT_OB_REGION_CPU_ADDR0_NBITS(nbits) |
> @@ -123,7 +123,7 @@ void cdns_pcie_set_outbound_region_for_normal_msg(struct cdns_pcie *pcie,
> }
>
> /* Set the CPU address */
> - if (pcie->ops->cpu_addr_fixup)
> + if (pcie->ops && pcie->ops->cpu_addr_fixup)
> cpu_addr = pcie->ops->cpu_addr_fixup(pcie, cpu_addr);
>
> addr0 = CDNS_PCIE_AT_OB_REGION_CPU_ADDR0_NBITS(17) |
> diff --git a/drivers/pci/controller/cadence/pcie-cadence.h b/drivers/pci/controller/cadence/pcie-cadence.h
> index 1d81c4bf6c6d..2f07ba661bda 100644
> --- a/drivers/pci/controller/cadence/pcie-cadence.h
> +++ b/drivers/pci/controller/cadence/pcie-cadence.h
> @@ -468,7 +468,7 @@ static inline u32 cdns_pcie_ep_fn_readl(struct cdns_pcie *pcie, u8 fn, u32 reg)
>
> static inline int cdns_pcie_start_link(struct cdns_pcie *pcie)
> {
> - if (pcie->ops->start_link)
> + if (pcie->ops && pcie->ops->start_link)
> return pcie->ops->start_link(pcie);
>
> return 0;
> @@ -476,13 +476,13 @@ static inline int cdns_pcie_start_link(struct cdns_pcie *pcie)
>
> static inline void cdns_pcie_stop_link(struct cdns_pcie *pcie)
> {
> - if (pcie->ops->stop_link)
> + if (pcie->ops && pcie->ops->stop_link)
> pcie->ops->stop_link(pcie);
> }
>
> static inline bool cdns_pcie_link_up(struct cdns_pcie *pcie)
> {
> - if (pcie->ops->link_up)
> + if (pcie->ops && pcie->ops->link_up)
> return pcie->ops->link_up(pcie);
>
> return true;
> --
> 2.34.1
>
