| From 18d3a7e2011e204596f6b60c1479d5bf58cb97ea Mon Sep 17 00:00:00 2001 |
| From: Bjorn Helgaas <bhelgaas@google.com> |
| Date: Tue, 29 Jan 2013 16:44:27 -0700 |
| Subject: [PATCH] Driver core: treat unregistered bus_types as having no |
| devices |
| |
| commit 4fa3e78be7e985ca814ce2aa0c09cbee404efcf7 upstream. |
| |
| 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 |
| |
| 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") |
| |
| Reported-by: Joonsoo Kim <js1304@gmail.com> |
| Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.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 12eec3f633b1..1913e74ee582 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, |
| -- |
| 1.8.5.2 |
| |
