patch "serial: uartlite: fix exit path null pointer" added to tty-linus

This is a note to let you know that I've just added the patch titled

serial: uartlite: fix exit path null pointer

to my tty git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty.git
in the tty-linus branch.

The patch will show up in the next release of the linux-next tree (usually sometime within the next 24 hours during the week.)

The patch will hopefully also be merged in Linus's tree for the next -rc kernel release.

If you have any questions about this process, please let me know.

From a553add0846f355a28ed4e81134012e4a1e280c2 Mon Sep 17 00:00:00 2001
From: Randy Dunlap <[email protected]>
Date: Mon, 16 Sep 2019 16:12:23 -0700
Subject: serial: uartlite: fix exit path null pointer

Call uart_unregister_driver() conditionally instead of unconditionally, only if it has been previously registered.

This uses driver.state, just as the sh-sci.c driver does.

Fixes this null pointer dereference in tty_unregister_driver(), since the 'driver' argument is null:

  general protection fault: 0000 [#1] PREEMPT SMP KASAN PTI
  RIP: 0010:tty_unregister_driver+0x25/0x1d0

---
 drivers/tty/serial/uartlite.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

index b8b912b5a8b9..06e79c11141d 100644
@@ -897,7 +897,8 @@ static int __init ulite_init(void)
 static void __exit ulite_exit(void)
 {
 	platform_driver_unregister(&ulite_platform_driver);
-	uart_unregister_driver(&ulite_uart_driver);
+	if (ulite_uart_driver.state)
+		uart_unregister_driver(&ulite_uart_driver);
 }
 
 module_init(ulite_init);

2.23.0