release/5.2.58/leds-lm3533-fix-use-after-free-on-unbind.patch

From 2515fc01cd1ace14aa49f56258e73974ef4ef0b6 Mon Sep 17 00:00:00 2001
From: Johan Hovold <johan@kernel.org>
Date: Mon, 1 Jun 2020 15:39:47 +0200
Subject: [PATCH] leds: lm3533: fix use-after-free on unbind

commit d584221e683bbd173738603b83a315f27d27d043 upstream.

Several MFD child drivers register their class devices directly under
the parent device. This means you cannot blindly do devres conversions
so that deregistration ends up being tied to the parent device,
something which leads to use-after-free on driver unbind when the class
device is released while still being registered.

Fixes: 50154e29e5cc ("leds: lm3533: Use devm_led_classdev_register")
Cc: stable <stable@vger.kernel.org>     # 4.6
Cc: Amitoj Kaur Chawla <amitoj1606@gmail.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>

diff --git a/drivers/leds/leds-lm3533.c b/drivers/leds/leds-lm3533.c
index 9504ad405aef..b3edee703193 100644
--- a/drivers/leds/leds-lm3533.c
+++ b/drivers/leds/leds-lm3533.c
@@ -694,7 +694,7 @@ static int lm3533_led_probe(struct platform_device *pdev)
 
 	platform_set_drvdata(pdev, led);
 
-	ret = devm_led_classdev_register(pdev->dev.parent, &led->cdev);
+	ret = led_classdev_register(pdev->dev.parent, &led->cdev);
 	if (ret) {
 		dev_err(&pdev->dev, "failed to register LED %d\n", pdev->id);
 		return ret;
@@ -704,13 +704,18 @@ static int lm3533_led_probe(struct platform_device *pdev)
 
 	ret = lm3533_led_setup(led, pdata);
 	if (ret)
-		return ret;
+		goto err_deregister;
 
 	ret = lm3533_ctrlbank_enable(&led->cb);
 	if (ret)
-		return ret;
+		goto err_deregister;
 
 	return 0;
+
+err_deregister:
+	led_classdev_unregister(&led->cdev);
+
+	return ret;
 }
 
 static int lm3533_led_remove(struct platform_device *pdev)
@@ -720,6 +725,7 @@ static int lm3533_led_remove(struct platform_device *pdev)
 	dev_dbg(&pdev->dev, "%s\n", __func__);
 
 	lm3533_ctrlbank_disable(&led->cb);
+	led_classdev_unregister(&led->cdev);
 
 	return 0;
 }
-- 
2.27.0