HID: hid-ntrig: Prevent memory leak in ntrig_report_version()

Use a scope-based cleanup helper for the buffer allocated with kmalloc()
in ntrig_report_version() to simplify the cleanup logic and prevent
memory leaks (specifically the !hid_is_usb()-case one).

[jkosina@suse.com: elaborate on the actual existing leak]
Fixes: 185c926283da ("HID: hid-ntrig: fix unable to handle page fault in ntrig_report_version()")
Signed-off-by: Masami Ichikawa <masami256@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.com>

diff --git a/drivers/hid/hid-ntrig.c b/drivers/hid/hid-ntrig.c
index 0f76e241e0afb4adb38885a008a05edb24169ea9..a7f10c45f62bdae24e9362ac1863e2440d184f7d 100644 (file)
--- a/drivers/hid/hid-ntrig.c
+++ b/drivers/hid/hid-ntrig.c
@@ -142,13 +142,13 @@ static void ntrig_report_version(struct hid_device *hdev)
        int ret;
        char buf[20];
        struct usb_device *usb_dev = hid_to_usb_dev(hdev);
-       unsigned char *data = kmalloc(8, GFP_KERNEL);
+       unsigned char *data __free(kfree) = kmalloc(8, GFP_KERNEL);
 
        if (!hid_is_usb(hdev))
                return;
 
        if (!data)
-               goto err_free;
+               return;
 
        ret = usb_control_msg(usb_dev, usb_rcvctrlpipe(usb_dev, 0),
                              USB_REQ_CLEAR_FEATURE,
@@ -163,9 +163,6 @@ static void ntrig_report_version(struct hid_device *hdev)
                hid_info(hdev, "Firmware version: %s (%02x%02x %02x%02x)\n",
                         buf, data[2], data[3], data[4], data[5]);
        }
-
-err_free:
-       kfree(data);
 }
 
 static ssize_t show_phys_width(struct device *dev,