[PATCH 1/2] topology: Check for missing CPU devices

[Ben Hutchings <ben@decadent.org.uk>]

Commit ccbc60d3e19a1b6ae66ca0d89b3da02dde62088b ('topology: Provide
CPU topology in sysfs in !SMP configurations') causes a crash at boot
on a several architectures.  The topology sysfs code assumes that
there is a CPU device for each online CPU whereas some architectures
that do not support SMP or cpufreq do not register any CPU devices.
Check for this before trying to use a device.

Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
 drivers/base/topology.c |    5 ++++-
 1 files changed, 4 insertions(+), 1 deletions(-)

diff --git a/drivers/base/topology.c b/drivers/base/topology.c
index ae989c5..4467c85 100644
--- a/drivers/base/topology.c
+++ b/drivers/base/topology.c
@@ -147,6 +147,8 @@ static int __cpuinit topology_add_dev(unsigned int cpu)
 {
 	struct device *dev = get_cpu_device(cpu);
 
+	if (!dev)
+		return -ENODEV;
 	return sysfs_create_group(&dev->kobj, &topology_attr_group);
 }
 
@@ -154,7 +156,8 @@ static void __cpuinit topology_remove_dev(unsigned int cpu)
 {
 	struct device *dev = get_cpu_device(cpu);
 
-	sysfs_remove_group(&dev->kobj, &topology_attr_group);
+	if (dev)
+		sysfs_remove_group(&dev->kobj, &topology_attr_group);
 }
 
 static int __cpuinit topology_cpu_callback(struct notifier_block *nfb,
-- 
1.7.8.2