On Wed, Sep 02, 2020 at 11:47:56PM -0400, Samuel Dionne-Riel wrote:
> On Wed, 2 Sep 2020 17:01:19 +0100
> Lorenzo Pieralisi <lorenzo.pieralisi@xxxxxxx> wrote:
>
> > On Tue, Sep 01, 2020 at 02:33:56PM -0400, Samuel Dionne-Riel wrote:
> >
> > Please print a pointer as a pointer and print both bus and
> > bus->parent.
>
> Hopefully pointer as a pointer is %px. Not sure what else, if that's
> wrong please tell.
>
> ---
> @@ -79,6 +79,8 @@ static int rockchip_pcie_valid_device(struct rockchip_pcie *rockchip,
> * do not read more than one device on the bus directly attached
> * to RC's downstream side.
> */
> + printk("[!!] // bus (%px) bus->parent (%px)\n", bus, bus->parent);
> + printk("[!!] bus->primary (%d) == rockchip->root_bus_nr (%d) && dev (%d) > 0\n", bus->primary, rockchip->root_bus_nr, dev);
> if (bus->primary == rockchip->root_bus_nr && dev > 0)
> return 0;
>
> --
>
> Again, two values, verified with a bit of set and `sort -u`.
>
> [ 1.691266] [!!] // bus (ffff0000ef9ab800) bus->parent (0000000000000000)
> [ 1.691271] [!!] bus->primary (0) == rockchip->root_bus_nr (0) && dev (0) > 0
>
> and
>
> [ 1.697156] [!!] // bus (ffff0000ef9ac000) bus->parent (ffff0000ef9ab800)
> [ 1.697160] [!!] bus->primary (0) == rockchip->root_bus_nr (0) && dev (0) > 0
>
> First instance of each shown here. Last time I don't think it was.
Ok I think I understand what the problem is.
Can you give this patch a shot please ? I think we are dereferencing
a NULL pointer if bus is the root bus and dev == 0, we can rewrite
the check if this patch fixes the issue.
-- >8 --
diff --git a/drivers/pci/controller/pcie-rockchip-host.c b/drivers/pci/controller/pcie-rockchip-host.c
index 0bb2fb3e8a0b..72beda87b47f 100644
--- a/drivers/pci/controller/pcie-rockchip-host.c
+++ b/drivers/pci/controller/pcie-rockchip-host.c
@@ -79,7 +79,7 @@ static int rockchip_pcie_valid_device(struct rockchip_pcie *rockchip,
* do not read more than one device on the bus directly attached
* to RC's downstream side.
*/
- if (pci_is_root_bus(bus->parent) && dev > 0)
+ if (bus->parent && pci_is_root_bus(bus->parent) && dev > 0)
return 0;
return 1;
