Messages in this thread | | | Date | Thu, 03 Sep 2020 16:59:30 +0100 | From | Marc Zyngier <> | Subject | Re: Boot failure on gru-scarlet-inx with 5.9-rc2 |
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On 2020-09-03 15:35, Rob Herring wrote: > On Thu, Sep 3, 2020 at 3:19 AM Lorenzo Pieralisi > <lorenzo.pieralisi@arm.com> wrote: >> >> 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@arm.com> 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. > > Indeed. I checked all the other cases of pci_is_root_bus(bus->parent) > and they should be fine because they are only reached if !root_bus. > > I would restructure the check like this instead: > > diff --git a/drivers/pci/controller/pcie-rockchip-host.c > b/drivers/pci/controller/pcie-rockchip-host.c > index 0bb2fb3e8a0b..9b485bea8b92 100644 > --- a/drivers/pci/controller/pcie-rockchip-host.c > +++ b/drivers/pci/controller/pcie-rockchip-host.c > @@ -72,14 +72,14 @@ static int rockchip_pcie_valid_device(struct > rockchip_pcie *rockchip, > struct pci_bus *bus, int dev) > { > /* access only one slot on each root port */ > - if (pci_is_root_bus(bus) && dev > 0) > - return 0; > - > - /* > - * 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 (pci_is_root_bus(bus)) > + if (dev > 0) > + return 0; > + else if (pci_is_root_bus(bus->parent) && dev > 0)
Careful here, this else is relative to the *closest* if, and not what the indentation suggests...
> + /* > + * do not read more than one device on the bus directly > attached > + * to RC's downstream side. > + */ > return 0; > > return 1;
M. -- Jazz is not dead. It just smells funny...
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