Andy Whitcroft <[email protected]> wrote:
>
> pci device sysdata may be null, check in pcibus_to_node
>
> We have been seeing panic's on NUMA systems in pci_call_probe() in
> 2.6.15-rc5-mm2 and -mm3. It seems that some changes have occured
> to the meaning of the 'sysdata' for a device such that it is no
> longer just an integer containing the node, it is now a structure
> containing the node and other data. However, it seems that we do not
> always initialise this sysdata before we probe the device.
>
> Below are three examples from a boot with this checked for. It is
> not clear to me whether it is reasonable to attempt to probe this
> device without the bus sysdata being initialised. The attached
> patch adds a safety check to pcibus_to_node() to avoid the panic,
> this restores the 'call anytime' semantic for this function.
>
> ...
>
> -#define pcibus_to_node(bus) ((struct pci_sysdata *)((bus)->sysdata))->node
> +#define pcibus_to_node(bus) (((bus)->sysdata)? ((struct pci_sysdata *)((bus)->sysdata))->node : -1)
> #define pcibus_to_cpumask(bus) node_to_cpumask(pcibus_to_node(bus))
>
It would be neater and faster to simply require that the platform always
put something sane bus->sysdata, even if that's a pointer to some
statically allocated struct. IOW:
static struct pci_sysdata dummy_sysdata = { .node = -1 };
somewhere_in_initialisation()
{
...
if (bus->sysdata == NULL)
bus->sysdata = dummy_sysdata;
}
-
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