diff options
| author | Bjorn Helgaas <bhelgaas@google.com> | 2013-01-29 16:44:27 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2013-02-03 17:55:29 -0800 |
| commit | 4fa3e78be7e985ca814ce2aa0c09cbee404efcf7 (patch) | |
| tree | 5afeff2353b3c6c1fd9ebad53c24ca8efcfe5371 | |
| parent | 422d26b6ecd77af8c77f2a40580679459825170f (diff) | |
| download | linux-4fa3e78be7e985ca814ce2aa0c09cbee404efcf7.tar.bz2 | |
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>
| -rw-r--r-- | drivers/base/bus.c | 4 |
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, |