linux-kernel - [PATCH 4/4] PM / devfreq: Check governor before using governor->name

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Message-ID: <20250421030020.3108405-5-zhenglifeng1@huawei.com>
Date: Mon, 21 Apr 2025 11:00:20 +0800
From: Lifeng Zheng <zhenglifeng1@...wei.com>
To: <myungjoo.ham@...sung.com>, <kyungmin.park@...sung.com>,
	<cw00.choi@...sung.com>
CC: <linux-pm@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
	<linuxarm@...wei.com>, <jonathan.cameron@...wei.com>,
	<zhanjie9@...ilicon.com>, <lihuisong@...wei.com>, <yubowen8@...wei.com>,
	<cenxinghai@...artners.com>, <zhenglifeng1@...wei.com>
Subject: [PATCH 4/4] PM / devfreq: Check governor before using governor->name

Commit 96ffcdf239de ("PM / devfreq: Remove redundant governor_name from
struct devfreq") removes governor_name and uses governor->name to replace
it. But devfreq->governor may be NULL and directly using
devfreq->governor->name may cause null pointer exception. Move the check of
governor to before using governor->name.

Fixes: 96ffcdf239de ("PM / devfreq: Remove redundant governor_name from struct devfreq")
Signed-off-by: Lifeng Zheng <zhenglifeng1@...wei.com>
---
 drivers/devfreq/devfreq.c | 10 +++-------
 1 file changed, 3 insertions(+), 7 deletions(-)

diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
index 18e3f7e063a4..46f3a8053197 100644
--- a/drivers/devfreq/devfreq.c
+++ b/drivers/devfreq/devfreq.c
@@ -1376,15 +1376,11 @@ int devfreq_remove_governor(struct devfreq_governor *governor)
 		int ret;
 		struct device *dev = devfreq->dev.parent;
 
+		if (!devfreq->governor)
+			continue;
+
 		if (!strncmp(devfreq->governor->name, governor->name,
 			     DEVFREQ_NAME_LEN)) {
-			/* we should have a devfreq governor! */
-			if (!devfreq->governor) {
-				dev_warn(dev, "%s: Governor %s NOT present\n",
-					 __func__, governor->name);
-				continue;
-				/* Fall through */
-			}
 			ret = devfreq->governor->event_handler(devfreq,
 						DEVFREQ_GOV_STOP, NULL);
 			if (ret) {
-- 
2.33.0