linux-kernel - [PATCH] cpufreq/longhaul: handle NULL policy in longhaul

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Message-ID: <20250828185440.9654-1-nanovim@gmail.com>
Date: Thu, 28 Aug 2025 20:54:35 +0200
From: Dennis Beier <nanovim@...il.com>
To: linux-kernel@...r.kernel.org
Cc: Dennis Beier <nanovim@...il.com>
Subject: [PATCH] cpufreq/longhaul: handle NULL policy in longhaul_exit

longhaul_exit() was calling cpufreq_cpu_get(0) without checking
for a NULL policy pointer. On some systems, this could lead to a
NULL dereference and a kernel warning or panic.

This patch adds a check using unlikely() and prints a warning
if the policy is NULL, then returns early. Also, the loop variable
is now declared inside the for-loop to match modern kernel style.

Bugzilla: #219962

Signed-off-by: Dennis Beier <nanovim@...il.com>
---
 drivers/cpufreq/longhaul.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/cpufreq/longhaul.c b/drivers/cpufreq/longhaul.c
index ba0e08c8486a..9698d56bfe6c 100644
--- a/drivers/cpufreq/longhaul.c
+++ b/drivers/cpufreq/longhaul.c
@@ -951,9 +951,14 @@ static int __init longhaul_init(void)
 static void __exit longhaul_exit(void)
 {
 	struct cpufreq_policy *policy = cpufreq_cpu_get(0);
-	int i;
+	if (unlikely(!policy)) {
+		pr_warn_once("longhaul_exit: policy is NULL\n");
+
+		return;
+	}
+
 
-	for (i = 0; i < numscales; i++) {
+	for (int i = 0; i < numscales; i++) {
 		if (mults[i] == maxmult) {
 			struct cpufreq_freqs freqs;
 
-- 
2.50.1