Thread (15 messages) 15 messages, 2 authors, 2020-04-21
STALE2353d

[PATCH 3/5] backlight: led_bl: add led_access locking

From: Tomi Valkeinen <hidden>
Date: 2020-04-17 11:33:42
Also in: dri-devel
Subsystem: backlight class/subsystem, framebuffer layer, the rest · Maintainers: Lee Jones, Daniel Thompson, Jingoo Han, Helge Deller, Linus Torvalds

led_bl does not lock 'led_access' when calling led_sysfs_disable and
led_sysfs_enable, causing the below WARN. Add the locking.

WARNING: CPU: 0 PID: 223 at drivers/leds/led-core.c:353 led_sysfs_disable+0x4c/0x5c

Signed-off-by: Tomi Valkeinen <redacted>
---
 drivers/video/backlight/led_bl.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)
diff --git a/drivers/video/backlight/led_bl.c b/drivers/video/backlight/led_bl.c
index c46ecdfe8b0a..63693c4f0883 100644
--- a/drivers/video/backlight/led_bl.c
+++ b/drivers/video/backlight/led_bl.c
@@ -216,8 +216,11 @@ static int led_bl_probe(struct platform_device *pdev)
 		return PTR_ERR(priv->bl_dev);
 	}
 
-	for (i = 0; i < priv->nb_leds; i++)
+	for (i = 0; i < priv->nb_leds; i++) {
+		mutex_lock(&priv->leds[i]->led_access);
 		led_sysfs_disable(priv->leds[i]);
+		mutex_unlock(&priv->leds[i]->led_access);
+	}
 
 	backlight_update_status(priv->bl_dev);
 
@@ -233,8 +236,11 @@ static int led_bl_remove(struct platform_device *pdev)
 	backlight_device_unregister(bl);
 
 	led_bl_power_off(priv);
-	for (i = 0; i < priv->nb_leds; i++)
+	for (i = 0; i < priv->nb_leds; i++) {
+		mutex_lock(&priv->leds[i]->led_access);
 		led_sysfs_enable(priv->leds[i]);
+		mutex_unlock(&priv->leds[i]->led_access);
+	}
 
 	return 0;
 }
-- 
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