linux-kernel - [PATCH v2 9/9] thermal/core: Protect thermal device operations against thermal device removal

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Date:   Thu, 10 Nov 2022 07:25:00 -0800
From:   Guenter Roeck <linux@...ck-us.net>
To:     "Rafael J . Wysocki" <rafael@...nel.org>,
        Daniel Lezcano <daniel.lezcano@...aro.org>
Cc:     Amit Kucheria <amitk@...nel.org>, Zhang Rui <rui.zhang@...el.com>,
        linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org,
        Guenter Roeck <linux@...ck-us.net>
Subject: [PATCH v2 9/9] thermal/core: Protect thermal device operations against thermal device removal

Thermal device operations may be called after thermal zone device removal.
After thermal zone device removal, thermal zone device operations must
no longer be called. To prevent such calls from happening, ensure that
the thermal device is registered before executing any thermal device
operations.

Signed-off-by: Guenter Roeck <linux@...ck-us.net>
---
v2: Fixed spelling error in description

 drivers/thermal/thermal_core.c | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/drivers/thermal/thermal_core.c b/drivers/thermal/thermal_core.c
index b8e3b262b2bd..aa0107f11c98 100644
--- a/drivers/thermal/thermal_core.c
+++ b/drivers/thermal/thermal_core.c
@@ -203,6 +203,9 @@ int thermal_zone_device_set_policy(struct thermal_zone_device *tz,
 	mutex_lock(&thermal_governor_lock);
 	mutex_lock(&tz->lock);
 
+	if (!device_is_registered(&tz->device))
+		goto exit;
+
 	gov = __find_governor(strim(policy));
 	if (!gov)
 		goto exit;
@@ -445,6 +448,12 @@ static int thermal_zone_device_set_mode(struct thermal_zone_device *tz,
 		return ret;
 	}
 
+	if (!device_is_registered(&tz->device)) {
+		mutex_unlock(&tz->lock);
+
+		return -ENODEV;
+	}
+
 	if (tz->ops->change_mode)
 		ret = tz->ops->change_mode(tz, mode);
 
@@ -486,7 +495,8 @@ void thermal_zone_device_update(struct thermal_zone_device *tz,
 				enum thermal_notify_event event)
 {
 	mutex_lock(&tz->lock);
-	__thermal_zone_device_update(tz, event);
+	if (device_is_registered(&tz->device))
+		__thermal_zone_device_update(tz, event);
 	mutex_unlock(&tz->lock);
 }
 EXPORT_SYMBOL_GPL(thermal_zone_device_update);
-- 
2.36.2