Messages in this thread | | | From | Daniel Axtens <> | Subject | Re: [PATCH] powerpc/pseries: extract host bridge from pci_bus prior to bus removal | Date | Fri, 16 Apr 2021 17:15:00 +1000 |
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Hi Tyrel,
> The pci_bus->bridge reference may no longer be valid after > pci_bus_remove() resulting in passing a bad value to device_unregister() > for the associated bridge device. > > Store the host_bridge reference in a separate variable prior to > pci_bus_remove(). > The patch certainly seems to do what you say. I'm not really up on the innards of PCI, so I'm struggling to figure out by what code path pci_bus_remove() might invalidate pci_bus->bridge? A quick look at pci_remove_bus was not very illuminating but I didn't chase down every call it made.
Kind regards, Daniel
> Fixes: 7340056567e3 ("powerpc/pci: Reorder pci bus/bridge unregistration during PHB removal") > Signed-off-by: Tyrel Datwyler <tyreld@linux.ibm.com> > --- > arch/powerpc/platforms/pseries/pci_dlpar.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/arch/powerpc/platforms/pseries/pci_dlpar.c b/arch/powerpc/platforms/pseries/pci_dlpar.c > index f9ae17e8a0f4..a8f9140a24fa 100644 > --- a/arch/powerpc/platforms/pseries/pci_dlpar.c > +++ b/arch/powerpc/platforms/pseries/pci_dlpar.c > @@ -50,6 +50,7 @@ EXPORT_SYMBOL_GPL(init_phb_dynamic); > int remove_phb_dynamic(struct pci_controller *phb) > { > struct pci_bus *b = phb->bus; > + struct pci_host_bridge *host_bridge = to_pci_host_bridge(b->bridge); > struct resource *res; > int rc, i; > > @@ -76,7 +77,8 @@ int remove_phb_dynamic(struct pci_controller *phb) > /* Remove the PCI bus and unregister the bridge device from sysfs */ > phb->bus = NULL; > pci_remove_bus(b); > - device_unregister(b->bridge); > + host_bridge->bus = NULL; > + device_unregister(&host_bridge->dev); > > /* Now release the IO resource */ > if (res->flags & IORESOURCE_IO) > -- > 2.27.0
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