Patch "thermal: core: Fix race between zone registration and system suspend" has been added to the 6.11-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    thermal: core: Fix race between zone registration and system suspend

to the 6.11-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     thermal-core-fix-race-between-zone-registration-and-.patch
and it can be found in the queue-6.11 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 7413b3ef37914926e309ab9e57b4050b81ef48b8
Author: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
Date:   Fri Oct 4 21:19:21 2024 +0200

    thermal: core: Fix race between zone registration and system suspend
    
    [ Upstream commit cdf771ab476bd9acb0948f3088a277d5c3cacc6b ]
    
    If the registration of a thermal zone takes place at the time when
    system suspend is started, thermal_pm_notify() can run before the new
    thermal zone is added to thermal_tz_list and its "suspended" flag will
    not be set.  Consequently, if __thermal_zone_device_update() is called
    for that thermal zone, it will not return early as expected which may
    cause some destructive interference with the system suspend or resume
    flow to occur.
    
    To avoid that, make thermal_zone_init_complete() introduced previously
    set the "suspended" flag for new thermal zones if it runs during system
    suspend or resume.
    
    Fixes: 4e814173a8c4 ("thermal: core: Fix thermal zone suspend-resume synchronization")
    Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
    Link: https://patch.msgid.link/8490245.NyiUUSuA9g@xxxxxxxxxxxxx
    Reviewed-by: Lukasz Luba <lukasz.luba@xxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/thermal/thermal_core.c b/drivers/thermal/thermal_core.c
index 91512a8cb49d9..a674469adad19 100644
--- a/drivers/thermal/thermal_core.c
+++ b/drivers/thermal/thermal_core.c
@@ -40,6 +40,8 @@ static DEFINE_MUTEX(thermal_governor_lock);
 
 static struct thermal_governor *def_governor;
 
+static bool thermal_pm_suspended;
+
 /*
  * Governor section: set of functions to handle thermal governors
  *
@@ -1356,6 +1358,14 @@ static void thermal_zone_init_complete(struct thermal_zone_device *tz)
 	mutex_lock(&tz->lock);
 
 	tz->state &= ~TZ_STATE_FLAG_INIT;
+	/*
+	 * If system suspend or resume is in progress at this point, the
+	 * new thermal zone needs to be marked as suspended because
+	 * thermal_pm_notify() has run already.
+	 */
+	if (thermal_pm_suspended)
+		tz->state |= TZ_STATE_FLAG_SUSPENDED;
+
 	__thermal_zone_device_update(tz, THERMAL_EVENT_UNSPECIFIED);
 
 	mutex_unlock(&tz->lock);
@@ -1544,10 +1554,10 @@ thermal_zone_device_register_with_trips(const char *type,
 		}
 	}
 
-	mutex_unlock(&thermal_list_lock);
-
 	thermal_zone_init_complete(tz);
 
+	mutex_unlock(&thermal_list_lock);
+
 	thermal_notify_tz_create(tz);
 
 	thermal_debug_tz_add(tz);
@@ -1768,6 +1778,8 @@ static int thermal_pm_notify(struct notifier_block *nb,
 	case PM_SUSPEND_PREPARE:
 		mutex_lock(&thermal_list_lock);
 
+		thermal_pm_suspended = true;
+
 		list_for_each_entry(tz, &thermal_tz_list, node)
 			thermal_zone_pm_prepare(tz);
 
@@ -1778,6 +1790,8 @@ static int thermal_pm_notify(struct notifier_block *nb,
 	case PM_POST_SUSPEND:
 		mutex_lock(&thermal_list_lock);
 
+		thermal_pm_suspended = false;
+
 		list_for_each_entry(tz, &thermal_tz_list, node)
 			thermal_zone_pm_complete(tz);