From: Randy Dunlap rdunlap@infradead.org
commit a553add0846f355a28ed4e81134012e4a1e280c2 upstream.
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
Fixes: 238b8721a554 ("[PATCH] serial uartlite driver") Signed-off-by: Randy Dunlap rdunlap@infradead.org Cc: stable stable@vger.kernel.org Cc: Peter Korsgaard jacmet@sunsite.dk Link: https://lore.kernel.org/r/9c8e6581-6fcc-a595-0897-4d90f5d710df@infradead.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/tty/serial/uartlite.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
--- a/drivers/tty/serial/uartlite.c +++ b/drivers/tty/serial/uartlite.c @@ -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);