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authorBjorn Helgaas <bhelgaas@google.com>2013-01-30 03:44:27 +0400
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-02-04 05:55:29 +0400
commit4fa3e78be7e985ca814ce2aa0c09cbee404efcf7 (patch)
tree5afeff2353b3c6c1fd9ebad53c24ca8efcfe5371 /drivers/base/bus.c
parent422d26b6ecd77af8c77f2a40580679459825170f (diff)
downloadlinux-4fa3e78be7e985ca814ce2aa0c09cbee404efcf7.tar.xz
Driver core: treat unregistered bus_types as having no devices
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> Cc: stable <stable@vger.kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/base/bus.c')
-rw-r--r--drivers/base/bus.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/drivers/base/bus.c b/drivers/base/bus.c
index f9d31320bd37..519865b53f76 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,