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

MR: https://gitlab.com/redhat/centos-stream/src/kernel/centos-stream-9/-/merge_requests/7099

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

JIRA: https://issues.redhat.com/browse/RHEL-100485

Signed-off-by: Ming Lei <ming.lei@redhat.com>

Approved-by: Rafael Aquini <raquini@redhat.com>
Approved-by: Jay Shin <jaeshin@redhat.com>
Approved-by: CKI KWF Bot <cki-ci-bot+kwf-gitlab-com@redhat.com>

Merged-by: Augusto Caringi <acaringi@redhat.com>

Author: caringi

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;