Staging: panel: fix oops on panel_cleanup_module

Check for null pardevice (not registered, ej: panel never attached,
inexistent parport, etc. )  before calling parport_release,
parport_unregister_device, and related funcs on module release.

Signed-off-by: Costantino Leandro <lcostantino@gmail.com>
Acked-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 12 insertions, 11 deletions

diff --git a/drivers/staging/panel/panel.c b/drivers/staging/panel/panel.c
index ab69c1bf36a8..c2747bc88c6f 100644
--- a/drivers/staging/panel/panel.c
+++ b/drivers/staging/panel/panel.c
@@ -2164,19 +2164,20 @@ static void __exit panel_cleanup_module(void)
         if (scan_timer.function != NULL)
                 del_timer(&scan_timer);
 
-        if (keypad_enabled)
-                misc_deregister(&keypad_dev);
+        if (pprt != NULL) {
+                if (keypad_enabled)
+                        misc_deregister(&keypad_dev);
+
+                if (lcd_enabled) {
+                        panel_lcd_print("\x0cLCD driver " PANEL_VERSION
+                                        "\nunloaded.\x1b[Lc\x1b[Lb\x1b[L-");
+                        misc_deregister(&lcd_dev);
+                }
 
-        if (lcd_enabled) {
-                panel_lcd_print("\x0cLCD driver " PANEL_VERSION
-                                "\nunloaded.\x1b[Lc\x1b[Lb\x1b[L-");
-                misc_deregister(&lcd_dev);
+                /* TODO: free all input signals */
+                parport_release(pprt);
+                parport_unregister_device(pprt);
         }
-
-        /* TODO: free all input signals */
-
-        parport_release(pprt);
-        parport_unregister_device(pprt);
         parport_unregister_driver(&panel_driver);
 }