HID: multitouch: prevent memleak with the allocated name

mt_free_input_name() was never called during .remove():
hid_hw_stop() removes the hid_input items in hdev->inputs, and so the
list is therefore empty after the call. In the end, we never free the
special names that has been allocated during .probe().

Restore the original name before freeing it to avoid acessing already
freed pointer.

This fixes a regression introduced by 49a5a827a ("HID: multitouch: append " Pen" to
the name of the stylus input")

Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

diff --git a/drivers/hid/hid-multitouch.c b/drivers/hid/hid-multitouch.c
index dc3ae5c56f563bf7735ba4c6ee4bffa0f24ccdd0..d39a5cede0b0a59f15f5e21d85d1913086624da6 100644 (file)
--- a/drivers/hid/hid-multitouch.c
+++ b/drivers/hid/hid-multitouch.c
@@ -264,9 +264,12 @@ static struct mt_class mt_classes[] = {
 static void mt_free_input_name(struct hid_input *hi)
 {
        struct hid_device *hdev = hi->report->device;
+       const char *name = hi->input->name;
 
-       if (hi->input->name != hdev->name)
-               kfree(hi->input->name);
+       if (name != hdev->name) {
+               hi->input->name = hdev->name;
+               kfree(name);
+       }
 }
 
 static ssize_t mt_show_quirks(struct device *dev,
@@ -1040,11 +1043,11 @@ static void mt_remove(struct hid_device *hdev)
        struct hid_input *hi;
 
        sysfs_remove_group(&hdev->dev.kobj, &mt_attribute_group);
-       hid_hw_stop(hdev);
-
        list_for_each_entry(hi, &hdev->inputs, list)
                mt_free_input_name(hi);
 
+       hid_hw_stop(hdev);
+
        kfree(td);
        hid_set_drvdata(hdev, NULL);
 }