linux-kernel - [PATCH 5.4 134/191] PM / devfreq: Check NULL governor in available_governors

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Date:   Tue,  7 Jan 2020 21:54:14 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Leonard Crestez <leonard.crestez@....com>,
        Matthias Kaehlcke <mka@...omium.org>,
        Chanwoo Choi <cw00.choi@...sung.com>
Subject: [PATCH 5.4 134/191] PM / devfreq: Check NULL governor in available_governors_show

From: Leonard Crestez <leonard.crestez@....com>

commit d68adc8f85cd757bd33c8d7b2660ad6f16f7f3dc upstream.

The governor is initialized after sysfs attributes become visible so in
theory the governor field can be NULL here.

Fixes: bcf23c79c4e46 ("PM / devfreq: Fix available_governor sysfs")
Signed-off-by: Leonard Crestez <leonard.crestez@....com>
Reviewed-by: Matthias Kaehlcke <mka@...omium.org>
Reviewed-by: Chanwoo Choi <cw00.choi@...sung.com>
Signed-off-by: Chanwoo Choi <cw00.choi@...sung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 drivers/devfreq/devfreq.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/devfreq/devfreq.c
+++ b/drivers/devfreq/devfreq.c
@@ -1196,7 +1196,7 @@ static ssize_t available_governors_show(
 	 * The devfreq with immutable governor (e.g., passive) shows
 	 * only own governor.
 	 */
-	if (df->governor->immutable) {
+	if (df->governor && df->governor->immutable) {
 		count = scnprintf(&buf[count], DEVFREQ_NAME_LEN,
 				  "%s ", df->governor_name);
 	/*