linux-kernel - [PATCH 2/2 v2] Input: atmel_mxt_ts - fix double free of input device

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Message-Id: <1410359581-16284-1-git-send-email-nick.dyer@itdev.co.uk>
Date:	Wed, 10 Sep 2014 15:33:01 +0100
From:	nick.dyer@...ev.co.uk
To:	Dmitry Torokhov <dmitry.torokhov@...il.com>,
	Stephen Warren <swarren@...dotorg.org>
Cc:	Yufeng Shen <miletus@...gle.com>,
	Daniel Kurtz <djkurtz@...omium.org>,
	Henrik Rydberg <rydberg@...omail.se>,
	Joonyoung Shim <jy0922.shim@...sung.com>,
	Alan Bowens <Alan.Bowens@...el.com>,
	linux-input@...r.kernel.org, linux-kernel@...r.kernel.org,
	Peter Meerwald <pmeerw@...erw.net>,
	Benson Leung <bleung@...omium.org>,
	Olof Johansson <olofj@...omium.org>,
	Sekhar Nori <nsekhar@...com>, Nick Dyer <nick.dyer@...ev.co.uk>
Subject: [PATCH 2/2 v2] Input: atmel_mxt_ts - fix double free of input device

From: Stephen Warren <swarren@...dotorg.org>

[reworked after comments by Dmitry Torokhov. Move free of input device into
separate function. Only call in paths that require it.]
Signed-off-by: Nick Dyer <nick.dyer@...ev.co.uk>
---
 drivers/input/touchscreen/atmel_mxt_ts.c | 18 +++++++++++++-----
 1 file changed, 13 insertions(+), 5 deletions(-)

diff --git a/drivers/input/touchscreen/atmel_mxt_ts.c b/drivers/input/touchscreen/atmel_mxt_ts.c
index d954b81..aaacf8b 100644
--- a/drivers/input/touchscreen/atmel_mxt_ts.c
+++ b/drivers/input/touchscreen/atmel_mxt_ts.c
@@ -1379,11 +1379,16 @@ static int mxt_get_info(struct mxt_data *data)
 	return 0;
 }
 
-static void mxt_free_object_table(struct mxt_data *data)
+static void mxt_free_input_device(struct mxt_data *data)
 {
-	input_unregister_device(data->input_dev);
-	data->input_dev = NULL;
+	if (data->input_dev) {
+		input_unregister_device(data->input_dev);
+		data->input_dev = NULL;
+	}
+}
 
+static void mxt_free_object_table(struct mxt_data *data)
+{
 	kfree(data->object_table);
 	data->object_table = NULL;
 	kfree(data->msg_buf);
@@ -1962,11 +1967,13 @@ static int mxt_load_fw(struct device *dev, const char *fn)
 		ret = mxt_lookup_bootloader_address(data, 0);
 		if (ret)
 			goto release_firmware;
+
+		mxt_free_input_device(data);
+		mxt_free_object_table(data);
 	} else {
 		enable_irq(data->irq);
 	}
 
-	mxt_free_object_table(data);
 	reinit_completion(&data->bl_completion);
 
 	ret = mxt_check_bootloader(data, MXT_WAITING_BOOTLOAD_CMD, false);
@@ -2215,6 +2222,7 @@ static int mxt_probe(struct i2c_client *client, const struct i2c_device_id *id)
 	return 0;
 
 err_free_object:
+	mxt_free_input_device(data);
 	mxt_free_object_table(data);
 err_free_irq:
 	free_irq(client->irq, data);
@@ -2229,7 +2237,7 @@ static int mxt_remove(struct i2c_client *client)
 
 	sysfs_remove_group(&client->dev.kobj, &mxt_attr_group);
 	free_irq(data->irq, data);
-	input_unregister_device(data->input_dev);
+	mxt_free_input_device(data);
 	mxt_free_object_table(data);
 	kfree(data);
 
-- 
1.9.1

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