lkml.org 
[lkml]   [2013]   [Jan]   [29]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
Date
SubjectRe: [PATCH] Driver core: treat unregistered bus_types as having no devices
On Tue, Jan 29, 2013 at 4:44 PM, Bjorn Helgaas <bhelgaas@google.com> 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 <bhelgaas@google.com>
> ---
> 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")


\
 
 \ /
  Last update: 2013-01-30 01:41    [W:0.048 / U:0.052 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site