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

nick.dyer
2014-09-09T14:51:07Z

From: Stephen Warren <swarren@wwwdotorg.org>

[reworked after comments by Dmitry Torokhov. Move free of input device into
separate function. Only call in paths that require it. Move mxt_initialize
after sysfs init, because otherwise an error in the sysfs init may interfere
with the async return from the firmware loader. Add guards for sysfs
functions. ]
Signed-off-by: Nick Dyer <nick.dyer@itdev.co.uk>
---
drivers/input/touchscreen/atmel_mxt_ts.c | 40 ++++++++++++++++++++++----------
1 file changed, 28 insertions(+), 12 deletions(-)

diff --git a/drivers/input/touchscreen/atmel_mxt_ts.c b/drivers/input/touchscreen/atmel_mxt_ts.c
index d954b81..65153c4 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);
@@ -1828,6 +1833,10 @@ static ssize_t mxt_fw_version_show(struct device *dev,
{
struct mxt_data *data = dev_get_drvdata(dev);
struct mxt_info *info = &data->info;
+
+ if (!data->object_table)
+ return -EINVAL;
+
return scnprintf(buf, PAGE_SIZE, "%u.%u.%02X\n",
info->version >> 4, info->version & 0xf, info->build);
}
@@ -1838,6 +1847,10 @@ static ssize_t mxt_hw_version_show(struct device *dev,
{
struct mxt_data *data = dev_get_drvdata(dev);
struct mxt_info *info = &data->info;
+
+ if (!data->object_table)
+ return -EINVAL;
+
return scnprintf(buf, PAGE_SIZE, "%u.%u\n",
info->family_id, info->variant_id);
}
@@ -1870,6 +1883,9 @@ static ssize_t mxt_object_show(struct device *dev,
int error;
u8 *obuf;

+ if (!data->object_table)
+ return -EINVAL;
+
/* Pre-allocate buffer large enough to hold max sized object. */
obuf = kmalloc(256, GFP_KERNEL);
if (!obuf)
@@ -1962,11 +1978,13 @@ 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);
@@ -2201,21 +2219,19 @@ static int mxt_probe(struct i2c_client *client, const struct i2c_device_id *id)

disable_irq(client->irq);

- error = mxt_initialize(data);
- if (error)
- goto err_free_irq;
-
error = sysfs_create_group(&client->dev.kobj, &mxt_attr_group);
if (error) {
dev_err(&client->dev, "Failure %d creating sysfs group\n",
error);
- goto err_free_object;
+ goto err_free_irq;
}

+ error = mxt_initialize(data);
+ if (error)
+ goto err_free_irq;
+
return 0;

-err_free_object:
- mxt_free_object_table(data);
err_free_irq:
free_irq(client->irq, data);
err_free_mem:
@@ -2229,7 +2245,7 @@ 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