serial: ifx6x60: fix use-after-free on module unload

commit 1e948479b3d63e3ac0ecca13cbf4921c7d17c168 upstream.

Make sure to deregister the SPI driver before releasing the tty driver
to avoid use-after-free in the SPI remove callback where the tty
devices are deregistered.

Fixes: 72d4724ea54c ("serial: ifx6x60: Add modem power off function in the platform reboot process")
Cc: stable <stable@vger.kernel.org>     # 3.8
Cc: Jun Chen <jun.d.chen@intel.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Willy Tarreau <w@1wt.eu>

diff --git a/drivers/tty/serial/ifx6x60.c b/drivers/tty/serial/ifx6x60.c
index 8b1534c424afc38eb022d26d7ba70b25e6b722d4..be3dc751dfbb3a49ae5f8fb79ef11954bf6ba949 100644 (file)
--- a/drivers/tty/serial/ifx6x60.c
+++ b/drivers/tty/serial/ifx6x60.c
@@ -1379,9 +1379,9 @@ static struct spi_driver ifx_spi_driver = {
 static void __exit ifx_spi_exit(void)
 {
        /* unregister */
+       spi_unregister_driver((void *)&ifx_spi_driver);
        tty_unregister_driver(tty_drv);
        put_tty_driver(tty_drv);
-       spi_unregister_driver((void *)&ifx_spi_driver);
        unregister_reboot_notifier(&ifx_modem_reboot_notifier_block);
 }