cpufreq: cppc: Set fie_disabled to FIE_DISABLED if fails to create kworker_fie

The function cppc_freq_invariance_init() may failed to create
kworker_fie, make it more robust by setting fie_disabled to FIE_DISBALED
to prevent an invalid pointer dereference in kthread_destroy_worker(),
which called from cppc_freq_invariance_exit().

Signed-off-by: Liao Chang <liaochang1@huawei.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

Author: Liao Chang

drivers/cpufreq/cppc_cpufreq.c

@@ -249,15 +249,19 @@ static void __init cppc_freq_invariance_init(void)
 		return;
 
 	kworker_fie = kthread_create_worker(0, "cppc_fie");
-	if (IS_ERR(kworker_fie))
+	if (IS_ERR(kworker_fie)) {
+		pr_warn("%s: failed to create kworker_fie: %ld\n", __func__,
+			PTR_ERR(kworker_fie));
+		fie_disabled = FIE_DISABLED;
 		return;
+	}
 
 	ret = sched_setattr_nocheck(kworker_fie->task, &attr);
 	if (ret) {
 		pr_warn("%s: failed to set SCHED_DEADLINE: %d\n", __func__,
 			ret);
 		kthread_destroy_worker(kworker_fie);
-		return;
+		fie_disabled = FIE_DISABLED;
 	}
 }
 
@@ -267,7 +271,6 @@ static void cppc_freq_invariance_exit(void)
 		return;
 
 	kthread_destroy_worker(kworker_fie);
-	kworker_fie = NULL;
 }
 
 #else