diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 974a7dfe3215..57360f5cdde4 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -1907,8 +1907,14 @@ void account_mm_sched(struct rq *rq, struct task_struct *p, s64 delta_exec)
 	/*
 	 * init_task, kthreads and user thread created
 	 * by user_mode_thread() don't have a cache group.
+	 * In theory a kernel thread does not have any valid
+	 * cache group, because sched_cache_fork() is not
+	 * invoked for a kernel thread - !grp should gate the
+	 * kernel thread. Use the PF_KTHREAD check explicitly
+	 * here for safety reasons, to guard against future
+	 * modifications and to pair with task_tick_cache().
 	 */
-	if (!grp || !grp->pcpu_sched)
+	if (p->flags & PF_KTHREAD || !grp || !grp->pcpu_sched)
 		return;
 
 	pcpu_sched = per_cpu_ptr(grp->pcpu_sched, cpu_of(rq));