Merge: lib/group_cpus: fix NULL pointer dereference from group_cpus_evenly()

MR: https://gitlab.com/redhat/centos-stream/src/kernel/centos-stream-10/-/merge_requests/1142

lib/group_cpus: fix NULL pointer dereference from group_cpus_evenly()

JIRA: https://issues.redhat.com/browse/RHEL-100484

Signed-off-by: Ming Lei <[email protected]>

Approved-by: Rafael Aquini <[email protected]>
Approved-by: Herton R. Krzesinski <[email protected]>
Approved-by: CKI KWF Bot <[email protected]>

Merged-by: Julio Faracco <[email protected]>

Author: jcfaracco

lib/group_cpus.c

@@ -352,6 +352,9 @@ struct cpumask *group_cpus_evenly(unsigned int numgrps)
 	int ret = -ENOMEM;
 	struct cpumask *masks = NULL;
 
+	if (numgrps == 0)
+		return NULL;
+
 	if (!zalloc_cpumask_var(&nmsk, GFP_KERNEL))
 		return NULL;
 
@@ -426,8 +429,12 @@ struct cpumask *group_cpus_evenly(unsigned int numgrps)
 #else /* CONFIG_SMP */
 struct cpumask *group_cpus_evenly(unsigned int numgrps)
 {
-	struct cpumask *masks = kcalloc(numgrps, sizeof(*masks), GFP_KERNEL);
+	struct cpumask *masks;
 
+	if (numgrps == 0)
+		return NULL;
+
+	masks = kcalloc(numgrps, sizeof(*masks), GFP_KERNEL);
 	if (!masks)
 		return NULL;