Merge tag 'driver-core-5.18-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core

Pull driver core fixes from Greg KH:
 "Here are some small driver core and kernfs fixes for some reported
  problems. They include:

   - kernfs regression that is causing oopses in 5.17 and newer releases

   - topology sysfs fixes for a few small reported problems.

  All of these have been in linux-next for a while with no reported
  issues"

* tag 'driver-core-5.18-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core:
  kernfs: fix NULL dereferencing in kernfs_remove
  topology: Fix up build warning in topology_is_visible()
  arch_topology: Do not set llc_sibling if llc_id is invalid
  topology: make core_mask include at least cluster_siblings
  topology/sysfs: Hide PPIN on systems that do not support it.

Author: torvalds

drivers/base/arch_topology.c

@@ -667,6 +667,15 @@ const struct cpumask *cpu_coregroup_mask(int cpu)
 			core_mask = &cpu_topology[cpu].llc_sibling;
 	}
 
+	/*
+	 * For systems with no shared cpu-side LLC but with clusters defined,
+	 * extend core_mask to cluster_siblings. The sched domain builder will
+	 * then remove MC as redundant with CLS if SCHED_CLUSTER is enabled.
+	 */
+	if (IS_ENABLED(CONFIG_SCHED_CLUSTER) &&
+	    cpumask_subset(core_mask, &cpu_topology[cpu].cluster_sibling))
+		core_mask = &cpu_topology[cpu].cluster_sibling;
+
 	return core_mask;
 }
 
@@ -684,7 +693,7 @@ void update_siblings_masks(unsigned int cpuid)
 	for_each_online_cpu(cpu) {
 		cpu_topo = &cpu_topology[cpu];
 
-		if (cpuid_topo->llc_id == cpu_topo->llc_id) {
+		if (cpu_topo->llc_id != -1 && cpuid_topo->llc_id == cpu_topo->llc_id) {
 			cpumask_set_cpu(cpu, &cpuid_topo->llc_sibling);
 			cpumask_set_cpu(cpuid, &cpu_topo->llc_sibling);
 		}

drivers/base/topology.c

@@ -152,9 +152,19 @@ static struct attribute *default_attrs[] = {
 	NULL
 };
 
+static umode_t topology_is_visible(struct kobject *kobj,
+				   struct attribute *attr, int unused)
+{
+	if (attr == &dev_attr_ppin.attr && !topology_ppin(kobj_to_dev(kobj)->id))
+		return 0;
+
+	return attr->mode;
+}
+
 static const struct attribute_group topology_attr_group = {
 	.attrs = default_attrs,
 	.bin_attrs = bin_attrs,
+	.is_visible = topology_is_visible,
 	.name = "topology"
 };
 

fs/kernfs/dir.c

@@ -1406,7 +1406,12 @@ static void __kernfs_remove(struct kernfs_node *kn)
  */
 void kernfs_remove(struct kernfs_node *kn)
 {
-	struct kernfs_root *root = kernfs_root(kn);
+	struct kernfs_root *root;
+
+	if (!kn)
+		return;
+
+	root = kernfs_root(kn);
 
 	down_write(&root->kernfs_rwsem);
 	__kernfs_remove(kn);