From: Johan Hovold <johan@kernel.org>
Date: Wed, 26 Apr 2017 10:23:04 +0000 (+0200)
Subject: staging: gdm724x: gdm_mux: fix use-after-free on module unload
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=5ac489a80ffb93b08e13017009b3f7617618d8d5;p=GitHub%2Fexynos8895%2Fandroid_kernel_samsung_universal8895.git

staging: gdm724x: gdm_mux: fix use-after-free on module unload

commit b58f45c8fc301fe83ee28cad3e64686c19e78f1c upstream.

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

Fixes: 61e121047645 ("staging: gdm7240: adding LTE USB driver")
Cc: Won Kang <wkang77@gmail.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/drivers/staging/gdm724x/gdm_mux.c b/drivers/staging/gdm724x/gdm_mux.c
index 445f83615575..fb4f3fea6c66 100644
--- a/drivers/staging/gdm724x/gdm_mux.c
+++ b/drivers/staging/gdm724x/gdm_mux.c
@@ -670,14 +670,14 @@ static int __init gdm_usb_mux_init(void)
 
 static void __exit gdm_usb_mux_exit(void)
 {
-	unregister_lte_tty_driver();
-
 	if (mux_rx_wq) {
 		flush_workqueue(mux_rx_wq);
 		destroy_workqueue(mux_rx_wq);
 	}
 
 	usb_deregister(&gdm_mux_driver);
+	unregister_lte_tty_driver();
+
 }
 
 module_init(gdm_usb_mux_init);