linux-kernel - [PATCH] thermal: gov_user_space: Do not lock thermal zone mutex

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Date:   Tue, 30 Aug 2022 20:15:38 +0200
From:   "Rafael J. Wysocki" <rjw@...ysocki.net>
To:     Linux PM <linux-pm@...r.kernel.org>
Cc:     LKML <linux-kernel@...r.kernel.org>,
        Zhang Rui <rui.zhang@...el.com>,
        Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>,
        Daniel Lezcano <daniel.lezcano@...aro.org>
Subject: [PATCH] thermal: gov_user_space: Do not lock thermal zone mutex

From: Rafael J. Wysocki <rafael.j.wysocki@...el.com>

Commit 670a5e356cb6 ("thermal/core: Move the thermal zone lock out of
the governors") moved thermal zone locking away from governors, but it
forgot about the user space one which deadlocks now.

Fix this by removing the thermal zone locking from the user space
governor.

Fixes: 670a5e356cb6 ("thermal/core: Move the thermal zone lock out of the governors")
Tested-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
---

linux-next material

---
 drivers/thermal/gov_user_space.c |    5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

Index: linux-pm/drivers/thermal/gov_user_space.c
===================================================================
--- linux-pm.orig/drivers/thermal/gov_user_space.c
+++ linux-pm/drivers/thermal/gov_user_space.c
@@ -34,7 +34,8 @@ static int notify_user_space(struct ther
 	char *thermal_prop[5];
 	int i;
 
-	mutex_lock(&tz->lock);
+	lockdep_assert_held(&tz->lock);
+
 	thermal_prop[0] = kasprintf(GFP_KERNEL, "NAME=%s", tz->type);
 	thermal_prop[1] = kasprintf(GFP_KERNEL, "TEMP=%d", tz->temperature);
 	thermal_prop[2] = kasprintf(GFP_KERNEL, "TRIP=%d", trip);
@@ -43,7 +44,7 @@ static int notify_user_space(struct ther
 	kobject_uevent_env(&tz->device.kobj, KOBJ_CHANGE, thermal_prop);
 	for (i = 0; i < 4; ++i)
 		kfree(thermal_prop[i]);
-	mutex_unlock(&tz->lock);
+
 	return 0;
 }