On Tue, Jan 29, 2013 at 4:44 PM, Bjorn Helgaas <[email protected]> wrote: > A bus_type has a list of devices (klist_devices), but the list and the > subsys_private structure that contains it are not initialized until the > bus_type is registered with bus_register(). > > The panic/reboot path has fixups that look up devices in pci_bus_type. If > we panic before registering pci_bus_type, the bus_type exists but the list > does not, so mach_reboot_fixups() trips over a null pointer and panics > again: > > mach_reboot_fixups > pci_get_device > .. > bus_find_device(&pci_bus_type, ...) > bus->p is NULL > > Signed-off-by: Bjorn Helgaas <[email protected]> > --- > drivers/base/bus.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/base/bus.c b/drivers/base/bus.c > index 24eb078..6856303 100644 > --- a/drivers/base/bus.c > +++ b/drivers/base/bus.c > @@ -290,7 +290,7 @@ int bus_for_each_dev(struct bus_type *bus, struct device > *start, > struct device *dev; > int error = 0; > > - if (!bus) > + if (!bus || !bus->p) > return -EINVAL; > > klist_iter_init_node(&bus->p->klist_devices, &i, > @@ -324,7 +324,7 @@ struct device *bus_find_device(struct bus_type *bus, > struct klist_iter i; > struct device *dev; > > - if (!bus) > + if (!bus || !bus->p) > return NULL; > > klist_iter_init_node(&bus->p->klist_devices, &i, >
Sorry, I meant to include this in the original post: Joonsoo reported a problem when panicking before PCI was initialized. I think this patch should be sufficient to replace the patch he posted here: https://lkml.org/lkml/2012/12/28/75 ("[PATCH] x86, reboot: skip reboot_fixups in early boot phase") -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
